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Papers by Paul Sparks

Research paper thumbnail of Catheter Ablation of Scar-related Ventricular Tachycardia: Procedural Results and Long-term Outcome in a Single-centre Series

Heart, Lung and Circulation, 2007

Background: Not all cardiac nurses work in 'glamorous', high profile units like CCU or cardiac su... more Background: Not all cardiac nurses work in 'glamorous', high profile units like CCU or cardiac surgery. Substantial amounts of cardiac care and management occur in areas like mine, a 30-bed cardiac and general medicine ward with elderly patients. Finding and keeping cardiac nurses in these areas can be difficult, but we determined to attract and retain enthusiastic nurses; support development of current staff whilst acknowledging and utilizing their skills and knowledge; develop a culture of on-going cardiac interest and education. Our unique unit-based program is designed to build a confident, competent, educated workforce. We designed the program to reflect adult learning principles; equip nurses with cardiac knowledge and skills relevant to our patient needs; be applicable for junior and senior nurses; demonstrate resource efficiency; be capable of scientific analysis. The programme included sequential learning packages; self directed learning; research activities; oral and written presentations; clinical placements; workshops and frequent academic detailing sessions. Participants progressed at their own pace in accordance with individual needs. Results: Subjective analysis had results p < 0.05 or better and Objective analysis using t-test had results p < 0.005 or better. Our outcomes include improved patient outcomes, extension of the programme to enrolled nurses and 'advanced' modules, formal cardiac research, and identification and implementation of best practice. Conclusions: It is possible to create an education programme that meets the education and practice needs of individual units within a hospital setting in a resource efficient way and to attract and retain cardiac skilled nurses into non critical settings.

Research paper thumbnail of Chronic Fish Oil Supplementation Reduces the Recurrence of Persistent Atrial Fibrillation after Cardioversion

Data Revues 14439506 V20ss2 S1443950611008377, 2011

Conclusion: Overall use of these medications at 30 days and 12 months was very good following PCI... more Conclusion: Overall use of these medications at 30 days and 12 months was very good following PCI. The frequency of medication use across the years at follow-up post-PCI is increasing.

Research paper thumbnail of Cardiomyopathy Arrhythmias: Implications for the Mechanisms of Tachycardia-Mediated Atrial Reversal of Atrial Mechanical Stunning After Cardioversion of Atrial

Background-Atrial mechanical stunning develops on termination of chronic atrial arrhythmias and i... more Background-Atrial mechanical stunning develops on termination of chronic atrial arrhythmias and is implicated in the genesis of thromboembolic complications after cardioversion. The mechanisms responsible for atrial mechanical stunning are unknown. The effects of atrial rate, isoproterenol, and calcium on atrial mechanical function in patients with atrial stunning have not been evaluated, and it is not known if atrial stunning can be reversed. Methods and Results-Thirty-five patients with chronic atrial flutter (AFL) undergoing radiofrequency ablation were studied. Fifteen patients in sinus rhythm undergoing ablation for paroxysmal AFL were studied as control for effects of the procedure. Left atrial appendage emptying velocities (LAAEVs) and spontaneous echocardiographic contrast (LASEC) were assessed by transesophageal echocardiography during AFL, after reversion to sinus rhythm, during atrial pacing at cycle lengths of 750 to 250 ms, after a postpacing pause, and with isoproterenol or calcium. With termination of AFL, LAAEV decreased from 59.0Ϯ3.7 cm/s to 18.8Ϯ1.4 cm/s (PϽ0.0001) and LASEC grade increased from 0.9Ϯ0.1 to 2.2Ϯ0.2 (PϽ0.0001). Pacing increased LAAEV to a maximum of 38.4Ϯ3.2 cm/s (PϽ0.0001) and reduced LASEC grade to 1.9Ϯ0.2 (Pϭ0.005). Isoproterenol and calcium reversed atrial mechanical stunning with LAAEV increasing to 89.3Ϯ12.6 cm/s (Pϭ0.0007) and 50.2Ϯ10.5 cm/s (Pϭ0.005), respectively, and LASEC grade decreasing to 0.2Ϯ0.1 (Pϭ0.001) and 1.4Ϯ0.2 (Pϭ0.01), respectively. The postpacing pause increased LAAEV to 69.3Ϯ3.7 cm/s (PϽ0.0001). No change in LAAEV was observed in the paroxysmal AFL group. Conclusion-Atrial mechanical stunning can be reversed by pacing at increased rates and through the administration of isoproterenol or calcium. These findings suggest a functional contractile apparatus in the mechanically remodeled atrium as a result of chronic atrial flutter. (Circulation. 2002;106:1806-1813.)

Research paper thumbnail of Effects of Chronic Omega-3 Polyunsaturated Fatty Acid Supplementation on Pulmonary Vein and Left Atrial Electrophysiology in Patients with Paroxysmal Atrial Fibrillation

Data Revues 14439506 V20ss2 S1443950611005749, Jul 28, 2011

BACKGROUND Atrial mechanical stunning is a form of tachycardia-mediated atrial cardiomyopathy tha... more BACKGROUND Atrial mechanical stunning is a form of tachycardia-mediated atrial cardiomyopathy that manifests after reversion of persistent atrial arrhythmias to sinus rhythm.

Research paper thumbnail of Reversal of Atrial Mechanical Stunning After Cardioversion of Atrial Arrhythmias Implications for the Mechanisms of Tachycardia-Mediated Atrial Cardiomyopathy

Research paper thumbnail of Abstract 14854: Chronic Fish Oil Supplementation in Humans Reduces the Recurrence of Persistent Atrial Fibrillation after Cardioversion

Circulation, Nov 22, 2011

Research paper thumbnail of Inducibility of Atrial Fibrillation in Absence of Structural Heart Disease or Clinical Atrial Fibrillation: Implications for the Use of Inducibility as an Endpoint for Atrial Fibrillation Ablation

Data Revues 14439506 V20ss2 S1443950611005828, Jul 28, 2011

Abstracts S97 2011;20S:S1-S155 CSANZ Abstracts 2011 sistent/longstanding persistent) randomised t... more Abstracts S97 2011;20S:S1-S155 CSANZ Abstracts 2011 sistent/longstanding persistent) randomised to either isolation of the pulmonary veins and posterior left atrium with a single ring of ablation lesions or wide antral isolation of the pulmonary veins, with or without left lateral mitral isthmus ablation, prior to their procedure and six months after. They were followed clinically and with seven-day Holter studies for arrhythmia recurrences.

Research paper thumbnail of Mapping and Ablation of Atrial Tachycardia

Circulation Journal Official Journal of the Japanese Circulation Society, Mar 1, 2003

... Melbourne Hospital. Morton Joseph B; Department of Cardiology, Royal Melbourne Hospital. Vohr... more ... Melbourne Hospital. Morton Joseph B; Department of Cardiology, Royal Melbourne Hospital. Vohra Jitu K; Department of Cardiology, Royal Melbourne Hospital. SparksPaul B; Department of Cardiology, Royal Melbourne Hospital. ...

Research paper thumbnail of Regional Left Atrial Remodelling in Paroxysmal Atrial Fibrillation Patients. Substrate for Recurrent AF Beyond The Pulmonary Veins?

Research paper thumbnail of Focal atrial tachycardia arising from the mitral annulus: electrocardiographic and electrophysiologic characterization

Journal of the American College of Cardiology, Jun 1, 2003

The study was done to characterize the electrocardiographic and electrophysiologic features of fo... more The study was done to characterize the electrocardiographic and electrophysiologic features of focal atrial tachycardia originating at the mitral annulus (MA). BACKGROUND Though the majority of left atrial tachycardias originate around the ostia of the pulmonary veins, only isolated reports have described focal tachycardia originating from the MA.

Research paper thumbnail of Abstract 15265: Extent of Elevation in Omega-3 Polyunsaturated Fatty Acid Levels in Blood is Directly and Strongly Related to Increases in Atrial Refractoriness and Susceptibility to Inducible Atrial Fibrillation in Humans

Circulation, Nov 22, 2011

Research paper thumbnail of Temporal Distribution of Arrhythmic Events in Chronic Kidney Disease:Highest Incidence in the Long Interdialytic Period

Heart Rhythm, 2015

Chronic kidney disease (CKD) patients on hemodialysis (HD) have a high risk of sudden cardiac dea... more Chronic kidney disease (CKD) patients on hemodialysis (HD) have a high risk of sudden cardiac death (SCD). A unique risk factor may be a longer interval between HD sessions (interdialytic period, IDP). Inherent in conventional HD (thrice-weekly) are two 48-hour short breaks (SIDP) and one 72-hour long break (LIDP) between HD sessions. We used an implantable cardiac monitor (ICM) to define the incidence and timing of significant arrhythmias in a HD population. 50 CKD patients on HD with LVEF &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 35% had an ICM inserted with intensive follow-up to record SCD events and pre-defined brady and tachy arrhythmias. Mean age 67±11 years; 72% male; mean follow-up 18±4 months. There were 8 unexpected SCD (16%), all during the LIDP. Terminal event was severe bradycardia with asystole in each recorded case. No episodes of polymorphic ventricular tachycardia (VT) occurred. 7686 arrhythmia events were recorded in 43 patients (86%) including: bradycardia in 15 pts (30%), sinus arrest in 14 pts (28%), 2° AV block in 4 pts (8%), non-sustained VT in 10 pts (20%) &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp; new onset paroxysmal atrial fibrillation in 14 pts (28%). The LIDP was the highest risk period for all arrhythmias (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.001). Arrhythmia event rate/hour was greatest during the 1(st) pre-HD period of the week compared to any other peri-HD period (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.001). Risk of SCD and significant arrhythmias are greatest during the LIDP. SCD was due to severe bradycardia and asystole. Interventions to prevent this type of SCD and/or shorten the LIDP deserve further evaluation. URL: https://www.anzctr.org.au, Unique identifier: ACTRN12613001326785.

Research paper thumbnail of Radiofrequency Ablation Electrophysiological Characteristics and Long-Term Outcomes of Atrial Tachycardia Arising From the Coronary Sinus Musculature

Research paper thumbnail of Radiofrequency Ablation Electrocardiographic and Electrophysiological Characterization and Focal Atrial Tachycardia From the Ostium of the Coronary Sinus

Research paper thumbnail of Node Disease: Evidence of Diffuse Atrial Remodeling Electrophysiological and Electroanatomic Characterization of the Atria in Sinus

Background-The normal sinus pacemaker complex is an extensive structure within the right atrium. ... more Background-The normal sinus pacemaker complex is an extensive structure within the right atrium. We hypothesized that patients with sinus node disease (SND) would have evidence of diffuse atrial abnormalities. Methods and Results-Sixteen patients with symptomatic SND and 16 age-matched controls were studied. The following were evaluated: effective refractory periods (ERPs) from the high and low lateral right atrium (RA), high septal RA, and distal coronary sinus (CS); conduction time along the CS and lateral RA; P-wave duration; and conduction at the crista terminalis. Electroanatomic mapping was performed to define the sinus node complex and determine regional conduction velocity, double potentials, fractionated electrograms, regional voltage, and areas of electrical silence. Patients with SND demonstrated significant increase in atrial ERP at all right atrial sites, increased atrial conduction time along the lateral RA and CS, prolongation of the P-wave duration, and greater number and duration of double potentials along the crista terminalis. Electroanatomic mapping demonstrated the sinus node complex in SND to be more often unicentric, localized to the low crista terminalis at the site of the largest residual voltage amplitude. There was significant regional conduction slowing with double potentials and fractionation associated with areas of low voltage and electrical silence (or scar). Conclusions-SND is associated with diffuse atrial remodeling characterized by structural change, conduction abnormalities, and increased right atrial refractoriness. There was a change in the nature of sinus pacemaker activity with loss of the normal multicentric pattern of activation, caudal shift of the pacemaker complex, and abnormal and circuitous conduction around lines of conduction block. (Circulation. 2004;109:1514-1522.)

Research paper thumbnail of Atrial fibrillation inducibility in the absence of structural heart disease or clinical atrial fibrillation: critical dependence on induction protocol, inducibility definition, and number of inductions

Circulation. Arrhythmia and electrophysiology, 2012

Inducibility of atrial fibrillation (AF) after pulmonary vein isolation has been used to guide ad... more Inducibility of atrial fibrillation (AF) after pulmonary vein isolation has been used to guide additional left atrial ablation in paroxysmal AF. The sensitivity and specificity of AF induction in this setting remains uncertain. We examined the incidence and characteristics of inducible AF in patients without structural heart disease or clinical AF and the effect of different induction protocols on AF inducibility. In 44 patients with supraventricular tachycardia with no history of AF or risk factors for AF, atrial refractoriness and conduction were measured, followed by AF induction attempts (10/patient). Each induction was performed after a waiting time that exceeded twice the duration of induced AF from the preceding induction. AF≥1 minute was considered inducible, and ≥5 minutes as sustained. Burst pacing (at 200 ms for 10 seconds) was compared to decremental pacing (from 200 ms to shortest cycle length, resulting in 1:1 atrial capture for 10 seconds). After 10 inductions, AF was...

Research paper thumbnail of Esophageal hematoma after atrial fibrillation ablation: incidence, clinical features, and sequelae of esophageal injury of a different sort

Circulation. Arrhythmia and electrophysiology, 2012

Esophageal hematoma recently has been reported as a form of esophageal injury after atrial fibril... more Esophageal hematoma recently has been reported as a form of esophageal injury after atrial fibrillation (AF) ablation, attributed to the use of transesophageal echocardiography (TEE). We sought to determine the incidence, clinical features, and sequelae of this form of esophageal injury. This was a prospective series of 1110 AF ablation procedures performed under general anesthesia (GA) over 9 years. TEE was inserted after induction of GA to exclude left atrial appendage thrombus, define cardiac function, and guide transseptal puncture. The procedural incidence of esophageal hematoma was 0.27% (3/1110 procedures, mortality 0%). Odonyphagia, regurgitation, and hoarseness were the predominant symptoms, with an onset within 12 hours. There was absence of fever and neurological symptoms. Chest computed tomography excluded atrio-esophageal fistula and was diagnostic of esophageal hematoma localized to either the upper esophagus or extending the length of the mid and lower esophagus; endo...

Research paper thumbnail of O104 Influence of the Long Interdialytic Break on the Incidence of Serious Arrhythmias and Sudden Cardiac Death in Patients with Chronic Kidney Disease (CKD) undergoing Haemodialysis

Research paper thumbnail of The Transesophageal Echo Probe May Contribute to Esophageal Injury After Catheter Ablation for Paroxysmal Atrial Fibrillation Under General Anesthesia: A Preliminary Observation

Journal of Cardiovascular Electrophysiology, 2014

The transesophageal echo probe (TEE) is commonly used before and during atrial fibrillation (AF) ... more The transesophageal echo probe (TEE) is commonly used before and during atrial fibrillation (AF) ablation under general anesthesia (GA). We sought to determine the potential contribution of the TEE probe to esophageal injury after pulmonary vein isolation (PVI) alone for paroxysmal AF. Seventy-six patients undergoing PVI with TEE, PVI/TEE, 16 undergoing PVI without TEE (PVI/No TEE), and 27 undergoing TEE without any left atrial ablation (TEE/No LA ablation) under GA were included. Posterior wall ablation was power (20-25 W) and time limited (electrogram attenuation or ≤30 s). Esophageal capsule endoscopy (n = 206) was performed pre- and post-procedure and at 2 weeks. Esophageal lesions were seen in 30% of PVI/TEE, 0% of patients in the PVI/No TEE (P = 0.009), and 22% of TEE/No LA ablation groups (P = 0.47 vs. PVI/TEE). There were no instances of esophageal bleeding, perforation, or need for gastrointestinal intervention. Self-resolving dysphagia was the only reported symptom (5%). All lesions healed within 2 weeks. There was no significant difference in the location or morphological appearance of esophageal lesions seen in the PVI/TEE versus TEE/No LA ablation groups. Esophageal lesions were seen in 30% of patients undergoing PVI alone under GA with use of TEE and in a similar proportion (22%) of patients undergoing TEE in the absence of left atrial ablation. This study makes the preliminary observation that one must be cognizant of the TEE probe as a potential contributor to esophageal injury after AF ablation. Larger studies are needed to confirm these findings.

Research paper thumbnail of Rapid Decline in Acute Stimulation Thresholds with Steroid-Eluting Active-Fixation Pacing Leads

Pacing and Clinical Electrophysiology, 2005

There is an increasing use of active-fixation leads for cardiac pacing, yet concerns remain regar... more There is an increasing use of active-fixation leads for cardiac pacing, yet concerns remain regarding initial high stimulation thresholds. The aim was to perform a detailed analysis of pacing parameters at the time of implantation to determine when lead repositioning should be considered. We performed a prospective observational study of consecutive new pacemaker implants. Detailed analysis of pacing parameters was collected at 2-minute intervals for 10 minutes, and at day 1 and week 8 following implant. Ninety-four patients underwent implantation of 79 dual-chamber and 15 single-chamber pacemakers using active-fixation leads in both chambers. An initial threshold of &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;1 V was demonstrated in 45/94 (48%) ventricular leads (mean threshold 1.5 +/- 0.3 V). This declined rapidly to 0.9 +/- 0.3 V at 4 minutes (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01), 0.7 +/- 0.3 V at 10 minutes (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01), and 0.6 +/- 0.3 V at day 1 (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01). At day 1, 43/45 leads were &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;1 V. There were 79 atrial leads. An initial threshold of &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;1 V (mean 1.7 +/- 0.6 V) was demonstrated in 41/79 (52%) leads falling significantly to 1.1 +/- 0.5 V at 4 minutes (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01), 0.9 +/- 0.4 V at 10 minutes (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01), and 0.6 +/- 0.2 V at day 1 (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01). At 10 minutes, 32 of 41 leads demonstrated a threshold of &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;1 V with all leads &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;1 V at day 1. Thresholds were maintained medium term. Active-fixation leads are commonly associated with initially high thresholds that fall rapidly. An initial threshold of 2 V should be provisionally accepted and retested at 4 minutes. The majority will have a threshold of &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;1 V the following day. A failure of a high threshold to decline at 4 minutes requires lead repositioning.

Research paper thumbnail of Catheter Ablation of Scar-related Ventricular Tachycardia: Procedural Results and Long-term Outcome in a Single-centre Series

Heart, Lung and Circulation, 2007

Background: Not all cardiac nurses work in 'glamorous', high profile units like CCU or cardiac su... more Background: Not all cardiac nurses work in 'glamorous', high profile units like CCU or cardiac surgery. Substantial amounts of cardiac care and management occur in areas like mine, a 30-bed cardiac and general medicine ward with elderly patients. Finding and keeping cardiac nurses in these areas can be difficult, but we determined to attract and retain enthusiastic nurses; support development of current staff whilst acknowledging and utilizing their skills and knowledge; develop a culture of on-going cardiac interest and education. Our unique unit-based program is designed to build a confident, competent, educated workforce. We designed the program to reflect adult learning principles; equip nurses with cardiac knowledge and skills relevant to our patient needs; be applicable for junior and senior nurses; demonstrate resource efficiency; be capable of scientific analysis. The programme included sequential learning packages; self directed learning; research activities; oral and written presentations; clinical placements; workshops and frequent academic detailing sessions. Participants progressed at their own pace in accordance with individual needs. Results: Subjective analysis had results p < 0.05 or better and Objective analysis using t-test had results p < 0.005 or better. Our outcomes include improved patient outcomes, extension of the programme to enrolled nurses and 'advanced' modules, formal cardiac research, and identification and implementation of best practice. Conclusions: It is possible to create an education programme that meets the education and practice needs of individual units within a hospital setting in a resource efficient way and to attract and retain cardiac skilled nurses into non critical settings.

Research paper thumbnail of Chronic Fish Oil Supplementation Reduces the Recurrence of Persistent Atrial Fibrillation after Cardioversion

Data Revues 14439506 V20ss2 S1443950611008377, 2011

Conclusion: Overall use of these medications at 30 days and 12 months was very good following PCI... more Conclusion: Overall use of these medications at 30 days and 12 months was very good following PCI. The frequency of medication use across the years at follow-up post-PCI is increasing.

Research paper thumbnail of Cardiomyopathy Arrhythmias: Implications for the Mechanisms of Tachycardia-Mediated Atrial Reversal of Atrial Mechanical Stunning After Cardioversion of Atrial

Background-Atrial mechanical stunning develops on termination of chronic atrial arrhythmias and i... more Background-Atrial mechanical stunning develops on termination of chronic atrial arrhythmias and is implicated in the genesis of thromboembolic complications after cardioversion. The mechanisms responsible for atrial mechanical stunning are unknown. The effects of atrial rate, isoproterenol, and calcium on atrial mechanical function in patients with atrial stunning have not been evaluated, and it is not known if atrial stunning can be reversed. Methods and Results-Thirty-five patients with chronic atrial flutter (AFL) undergoing radiofrequency ablation were studied. Fifteen patients in sinus rhythm undergoing ablation for paroxysmal AFL were studied as control for effects of the procedure. Left atrial appendage emptying velocities (LAAEVs) and spontaneous echocardiographic contrast (LASEC) were assessed by transesophageal echocardiography during AFL, after reversion to sinus rhythm, during atrial pacing at cycle lengths of 750 to 250 ms, after a postpacing pause, and with isoproterenol or calcium. With termination of AFL, LAAEV decreased from 59.0Ϯ3.7 cm/s to 18.8Ϯ1.4 cm/s (PϽ0.0001) and LASEC grade increased from 0.9Ϯ0.1 to 2.2Ϯ0.2 (PϽ0.0001). Pacing increased LAAEV to a maximum of 38.4Ϯ3.2 cm/s (PϽ0.0001) and reduced LASEC grade to 1.9Ϯ0.2 (Pϭ0.005). Isoproterenol and calcium reversed atrial mechanical stunning with LAAEV increasing to 89.3Ϯ12.6 cm/s (Pϭ0.0007) and 50.2Ϯ10.5 cm/s (Pϭ0.005), respectively, and LASEC grade decreasing to 0.2Ϯ0.1 (Pϭ0.001) and 1.4Ϯ0.2 (Pϭ0.01), respectively. The postpacing pause increased LAAEV to 69.3Ϯ3.7 cm/s (PϽ0.0001). No change in LAAEV was observed in the paroxysmal AFL group. Conclusion-Atrial mechanical stunning can be reversed by pacing at increased rates and through the administration of isoproterenol or calcium. These findings suggest a functional contractile apparatus in the mechanically remodeled atrium as a result of chronic atrial flutter. (Circulation. 2002;106:1806-1813.)

Research paper thumbnail of Effects of Chronic Omega-3 Polyunsaturated Fatty Acid Supplementation on Pulmonary Vein and Left Atrial Electrophysiology in Patients with Paroxysmal Atrial Fibrillation

Data Revues 14439506 V20ss2 S1443950611005749, Jul 28, 2011

BACKGROUND Atrial mechanical stunning is a form of tachycardia-mediated atrial cardiomyopathy tha... more BACKGROUND Atrial mechanical stunning is a form of tachycardia-mediated atrial cardiomyopathy that manifests after reversion of persistent atrial arrhythmias to sinus rhythm.

Research paper thumbnail of Reversal of Atrial Mechanical Stunning After Cardioversion of Atrial Arrhythmias Implications for the Mechanisms of Tachycardia-Mediated Atrial Cardiomyopathy

Research paper thumbnail of Abstract 14854: Chronic Fish Oil Supplementation in Humans Reduces the Recurrence of Persistent Atrial Fibrillation after Cardioversion

Circulation, Nov 22, 2011

Research paper thumbnail of Inducibility of Atrial Fibrillation in Absence of Structural Heart Disease or Clinical Atrial Fibrillation: Implications for the Use of Inducibility as an Endpoint for Atrial Fibrillation Ablation

Data Revues 14439506 V20ss2 S1443950611005828, Jul 28, 2011

Abstracts S97 2011;20S:S1-S155 CSANZ Abstracts 2011 sistent/longstanding persistent) randomised t... more Abstracts S97 2011;20S:S1-S155 CSANZ Abstracts 2011 sistent/longstanding persistent) randomised to either isolation of the pulmonary veins and posterior left atrium with a single ring of ablation lesions or wide antral isolation of the pulmonary veins, with or without left lateral mitral isthmus ablation, prior to their procedure and six months after. They were followed clinically and with seven-day Holter studies for arrhythmia recurrences.

Research paper thumbnail of Mapping and Ablation of Atrial Tachycardia

Circulation Journal Official Journal of the Japanese Circulation Society, Mar 1, 2003

... Melbourne Hospital. Morton Joseph B; Department of Cardiology, Royal Melbourne Hospital. Vohr... more ... Melbourne Hospital. Morton Joseph B; Department of Cardiology, Royal Melbourne Hospital. Vohra Jitu K; Department of Cardiology, Royal Melbourne Hospital. SparksPaul B; Department of Cardiology, Royal Melbourne Hospital. ...

Research paper thumbnail of Regional Left Atrial Remodelling in Paroxysmal Atrial Fibrillation Patients. Substrate for Recurrent AF Beyond The Pulmonary Veins?

Research paper thumbnail of Focal atrial tachycardia arising from the mitral annulus: electrocardiographic and electrophysiologic characterization

Journal of the American College of Cardiology, Jun 1, 2003

The study was done to characterize the electrocardiographic and electrophysiologic features of fo... more The study was done to characterize the electrocardiographic and electrophysiologic features of focal atrial tachycardia originating at the mitral annulus (MA). BACKGROUND Though the majority of left atrial tachycardias originate around the ostia of the pulmonary veins, only isolated reports have described focal tachycardia originating from the MA.

Research paper thumbnail of Abstract 15265: Extent of Elevation in Omega-3 Polyunsaturated Fatty Acid Levels in Blood is Directly and Strongly Related to Increases in Atrial Refractoriness and Susceptibility to Inducible Atrial Fibrillation in Humans

Circulation, Nov 22, 2011

Research paper thumbnail of Temporal Distribution of Arrhythmic Events in Chronic Kidney Disease:Highest Incidence in the Long Interdialytic Period

Heart Rhythm, 2015

Chronic kidney disease (CKD) patients on hemodialysis (HD) have a high risk of sudden cardiac dea... more Chronic kidney disease (CKD) patients on hemodialysis (HD) have a high risk of sudden cardiac death (SCD). A unique risk factor may be a longer interval between HD sessions (interdialytic period, IDP). Inherent in conventional HD (thrice-weekly) are two 48-hour short breaks (SIDP) and one 72-hour long break (LIDP) between HD sessions. We used an implantable cardiac monitor (ICM) to define the incidence and timing of significant arrhythmias in a HD population. 50 CKD patients on HD with LVEF &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 35% had an ICM inserted with intensive follow-up to record SCD events and pre-defined brady and tachy arrhythmias. Mean age 67±11 years; 72% male; mean follow-up 18±4 months. There were 8 unexpected SCD (16%), all during the LIDP. Terminal event was severe bradycardia with asystole in each recorded case. No episodes of polymorphic ventricular tachycardia (VT) occurred. 7686 arrhythmia events were recorded in 43 patients (86%) including: bradycardia in 15 pts (30%), sinus arrest in 14 pts (28%), 2° AV block in 4 pts (8%), non-sustained VT in 10 pts (20%) &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp; new onset paroxysmal atrial fibrillation in 14 pts (28%). The LIDP was the highest risk period for all arrhythmias (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.001). Arrhythmia event rate/hour was greatest during the 1(st) pre-HD period of the week compared to any other peri-HD period (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.001). Risk of SCD and significant arrhythmias are greatest during the LIDP. SCD was due to severe bradycardia and asystole. Interventions to prevent this type of SCD and/or shorten the LIDP deserve further evaluation. URL: https://www.anzctr.org.au, Unique identifier: ACTRN12613001326785.

Research paper thumbnail of Radiofrequency Ablation Electrophysiological Characteristics and Long-Term Outcomes of Atrial Tachycardia Arising From the Coronary Sinus Musculature

Research paper thumbnail of Radiofrequency Ablation Electrocardiographic and Electrophysiological Characterization and Focal Atrial Tachycardia From the Ostium of the Coronary Sinus

Research paper thumbnail of Node Disease: Evidence of Diffuse Atrial Remodeling Electrophysiological and Electroanatomic Characterization of the Atria in Sinus

Background-The normal sinus pacemaker complex is an extensive structure within the right atrium. ... more Background-The normal sinus pacemaker complex is an extensive structure within the right atrium. We hypothesized that patients with sinus node disease (SND) would have evidence of diffuse atrial abnormalities. Methods and Results-Sixteen patients with symptomatic SND and 16 age-matched controls were studied. The following were evaluated: effective refractory periods (ERPs) from the high and low lateral right atrium (RA), high septal RA, and distal coronary sinus (CS); conduction time along the CS and lateral RA; P-wave duration; and conduction at the crista terminalis. Electroanatomic mapping was performed to define the sinus node complex and determine regional conduction velocity, double potentials, fractionated electrograms, regional voltage, and areas of electrical silence. Patients with SND demonstrated significant increase in atrial ERP at all right atrial sites, increased atrial conduction time along the lateral RA and CS, prolongation of the P-wave duration, and greater number and duration of double potentials along the crista terminalis. Electroanatomic mapping demonstrated the sinus node complex in SND to be more often unicentric, localized to the low crista terminalis at the site of the largest residual voltage amplitude. There was significant regional conduction slowing with double potentials and fractionation associated with areas of low voltage and electrical silence (or scar). Conclusions-SND is associated with diffuse atrial remodeling characterized by structural change, conduction abnormalities, and increased right atrial refractoriness. There was a change in the nature of sinus pacemaker activity with loss of the normal multicentric pattern of activation, caudal shift of the pacemaker complex, and abnormal and circuitous conduction around lines of conduction block. (Circulation. 2004;109:1514-1522.)

Research paper thumbnail of Atrial fibrillation inducibility in the absence of structural heart disease or clinical atrial fibrillation: critical dependence on induction protocol, inducibility definition, and number of inductions

Circulation. Arrhythmia and electrophysiology, 2012

Inducibility of atrial fibrillation (AF) after pulmonary vein isolation has been used to guide ad... more Inducibility of atrial fibrillation (AF) after pulmonary vein isolation has been used to guide additional left atrial ablation in paroxysmal AF. The sensitivity and specificity of AF induction in this setting remains uncertain. We examined the incidence and characteristics of inducible AF in patients without structural heart disease or clinical AF and the effect of different induction protocols on AF inducibility. In 44 patients with supraventricular tachycardia with no history of AF or risk factors for AF, atrial refractoriness and conduction were measured, followed by AF induction attempts (10/patient). Each induction was performed after a waiting time that exceeded twice the duration of induced AF from the preceding induction. AF≥1 minute was considered inducible, and ≥5 minutes as sustained. Burst pacing (at 200 ms for 10 seconds) was compared to decremental pacing (from 200 ms to shortest cycle length, resulting in 1:1 atrial capture for 10 seconds). After 10 inductions, AF was...

Research paper thumbnail of Esophageal hematoma after atrial fibrillation ablation: incidence, clinical features, and sequelae of esophageal injury of a different sort

Circulation. Arrhythmia and electrophysiology, 2012

Esophageal hematoma recently has been reported as a form of esophageal injury after atrial fibril... more Esophageal hematoma recently has been reported as a form of esophageal injury after atrial fibrillation (AF) ablation, attributed to the use of transesophageal echocardiography (TEE). We sought to determine the incidence, clinical features, and sequelae of this form of esophageal injury. This was a prospective series of 1110 AF ablation procedures performed under general anesthesia (GA) over 9 years. TEE was inserted after induction of GA to exclude left atrial appendage thrombus, define cardiac function, and guide transseptal puncture. The procedural incidence of esophageal hematoma was 0.27% (3/1110 procedures, mortality 0%). Odonyphagia, regurgitation, and hoarseness were the predominant symptoms, with an onset within 12 hours. There was absence of fever and neurological symptoms. Chest computed tomography excluded atrio-esophageal fistula and was diagnostic of esophageal hematoma localized to either the upper esophagus or extending the length of the mid and lower esophagus; endo...

Research paper thumbnail of O104 Influence of the Long Interdialytic Break on the Incidence of Serious Arrhythmias and Sudden Cardiac Death in Patients with Chronic Kidney Disease (CKD) undergoing Haemodialysis

Research paper thumbnail of The Transesophageal Echo Probe May Contribute to Esophageal Injury After Catheter Ablation for Paroxysmal Atrial Fibrillation Under General Anesthesia: A Preliminary Observation

Journal of Cardiovascular Electrophysiology, 2014

The transesophageal echo probe (TEE) is commonly used before and during atrial fibrillation (AF) ... more The transesophageal echo probe (TEE) is commonly used before and during atrial fibrillation (AF) ablation under general anesthesia (GA). We sought to determine the potential contribution of the TEE probe to esophageal injury after pulmonary vein isolation (PVI) alone for paroxysmal AF. Seventy-six patients undergoing PVI with TEE, PVI/TEE, 16 undergoing PVI without TEE (PVI/No TEE), and 27 undergoing TEE without any left atrial ablation (TEE/No LA ablation) under GA were included. Posterior wall ablation was power (20-25 W) and time limited (electrogram attenuation or ≤30 s). Esophageal capsule endoscopy (n = 206) was performed pre- and post-procedure and at 2 weeks. Esophageal lesions were seen in 30% of PVI/TEE, 0% of patients in the PVI/No TEE (P = 0.009), and 22% of TEE/No LA ablation groups (P = 0.47 vs. PVI/TEE). There were no instances of esophageal bleeding, perforation, or need for gastrointestinal intervention. Self-resolving dysphagia was the only reported symptom (5%). All lesions healed within 2 weeks. There was no significant difference in the location or morphological appearance of esophageal lesions seen in the PVI/TEE versus TEE/No LA ablation groups. Esophageal lesions were seen in 30% of patients undergoing PVI alone under GA with use of TEE and in a similar proportion (22%) of patients undergoing TEE in the absence of left atrial ablation. This study makes the preliminary observation that one must be cognizant of the TEE probe as a potential contributor to esophageal injury after AF ablation. Larger studies are needed to confirm these findings.

Research paper thumbnail of Rapid Decline in Acute Stimulation Thresholds with Steroid-Eluting Active-Fixation Pacing Leads

Pacing and Clinical Electrophysiology, 2005

There is an increasing use of active-fixation leads for cardiac pacing, yet concerns remain regar... more There is an increasing use of active-fixation leads for cardiac pacing, yet concerns remain regarding initial high stimulation thresholds. The aim was to perform a detailed analysis of pacing parameters at the time of implantation to determine when lead repositioning should be considered. We performed a prospective observational study of consecutive new pacemaker implants. Detailed analysis of pacing parameters was collected at 2-minute intervals for 10 minutes, and at day 1 and week 8 following implant. Ninety-four patients underwent implantation of 79 dual-chamber and 15 single-chamber pacemakers using active-fixation leads in both chambers. An initial threshold of &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;1 V was demonstrated in 45/94 (48%) ventricular leads (mean threshold 1.5 +/- 0.3 V). This declined rapidly to 0.9 +/- 0.3 V at 4 minutes (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01), 0.7 +/- 0.3 V at 10 minutes (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01), and 0.6 +/- 0.3 V at day 1 (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01). At day 1, 43/45 leads were &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;1 V. There were 79 atrial leads. An initial threshold of &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;1 V (mean 1.7 +/- 0.6 V) was demonstrated in 41/79 (52%) leads falling significantly to 1.1 +/- 0.5 V at 4 minutes (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01), 0.9 +/- 0.4 V at 10 minutes (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01), and 0.6 +/- 0.2 V at day 1 (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01). At 10 minutes, 32 of 41 leads demonstrated a threshold of &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;1 V with all leads &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;1 V at day 1. Thresholds were maintained medium term. Active-fixation leads are commonly associated with initially high thresholds that fall rapidly. An initial threshold of 2 V should be provisionally accepted and retested at 4 minutes. The majority will have a threshold of &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;1 V the following day. A failure of a high threshold to decline at 4 minutes requires lead repositioning.