Echocardiographic predictors of functional class changes during cardiac resynchronization therapy: results from the MIRACLE trial (original) (raw)
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Catheter Ablation of Accessory Pathway in the Treatment of Pacemaker-Mediated Tachycardia
Pacing and Clinical Electrophysiology, 2012
Pacemaker-mediated tachycardia (PMT) remains a clinical problem in patients with dual-chamber pacemaker despite technological advances. The onset mechanism of this tachycardia is sensing of retrograde atrial activation after ventricular stimulation. Repeated retrograde conduction perpetuates tachycardia. Postventricular atrial refractory period prolongation has been used for prevention of PMT, but this is not the solution in all cases. We present a case with PMT where the retrograde limb is a left accessory pathway, which is treated with radiofrequency ablation successfully. (PACE 2012; 35:e74-e76)
Characteristics of Right Atrial Activation During Coronary Sinus Pacing
Journal of Cardiovascular Electrophysiology, 2002
Activation Patterns and Coronary Sinus Pacing. Introduction: Anatomic and electrical connections between the left atrium and right atrium (RA) have been described. The relationship between coronary sinus (CS) pacing site and RA activation has not been examined.
Journal of Cardiovascular Development and Disease
Introduction: Biventricular pacing has been the gold standard for cardiac resynchronization therapy in patients with left bundle branch block and severely reduced left ventricular ejection fraction for decades. However, in the past few years, this role has been challenged by the promising results of conduction system pacing in these patients, which has proven non-inferior and, at times, superior to biventricular pacing regarding left ventricular function outcomes. One of the most important limitations of both procedures is the long fluoroscopy times. Case description: We present the case of a 60-year-old patient with non-ischemic dilated cardiomyopathy and left bundle branch block in whom conduction system pacing was chosen as the first option for resynchronization therapy. A 3D electro-anatomical mapping system was used to guide the lead to the His bundle region, where correction was observed at high amplitudes, and afterward to the optimal septal penetration site. After reaching t...
The American Journal of Cardiology, 1992
Background. Two catheter electrode systems were compared for delivering radiofrequency current for ablation of the atrioventricular junction. Seventeen patients with drug-resistant supraventricular tachyarrhythmias were studied. Methods and Results. A 6F or 7F catheter with six or eight standard electrodes (1.25 mm wide, 2.5-mm spacing) was used in the first seven patients (group 1). A 7F quadripolar catheter with a large-tip electrode (4 mm long; surface area, 27 mm2) was used in the final 10 patients (group 2). Both ablation catheters were positioned to record a large atrial potential and a small but sharp His bundle potential from the distal bipolar electrode pair. Radiofrequency current was applied between a large skin electrode on the left posterior chest and either 1) each individual electrode on the standard-tip electrode catheter at 40 V (group 1) or 2) the large-tip electrode at 50-60 V (group 2). Radiofrequency current was limited to 40 V in group patients because of the strong potential for an early impedance rise when higher voltage is applied through standard electrodes. Complete atrioventricular block was achieved in six of seven group 1 patients and all 10 group 2 patients. A junctional escape rhythm followed ablation in five or six group 1 patients (mean cycle length, 1,066±162 msec) and eight of 10 group 2 patients (mean cycle length, 1,281±231 msec). Atrioventricular block was produced in a mean of 4.7±4.6 radiofrequency current applications delivered over a period of 42+±45 minutes using the large-tip electrode (group 2) compared with 46±22 applications using standard electrodes (15.9±10.2 applications delivered through the standard-tip electrode) over a period of 147±59 minutes (group 1). For the application producing atrioventricular block, the large-tip electrode used higher voltage (58±17 versus 38+5 V, p <0.03) and had lower impedance (103±22 versus 148+40Qk, p <0.01), resulting in greater power (33.0±13.0 versus 10.2 ±0.6 W, p <0.003) and shorter time to block (8±3 versus 22±3 seconds, p <0.001). Current delivery through standard electrodes was limited by an impedance rise occurring 7±7 seconds after the onset of one or more radiofrequency current applications at 10±1 W in six of seven patients. Using the large-tip electrode, an impedance rise occurred in five of 10 patients, but at 25±10 W and after 21±9 seconds. Atrioventricular block occurred before the impedance rise in three of these five patients. Complete atrioventricular block persisted in 15 of 16 patients at a mean follow-up of 8.7 months. Atrioventricular conduction returned at 1 month in one group 2 patient and was successfully ablated by a second procedure. Three group 1 patients died 0.5-2 months after ablation, and a fourth patient underwent cardiac transplantation after 10 months. Pathological examination of the heart in two of these patients showed necrosis of the atrioventricular node and origin of the His bundle, without injury to the middle or distal His bundle. All 10 group 2 patients are alive and subjectively improved after ablation. Conclusions. We conclude that catheter-delivered radiofrequency current effectively produces complete atrioventricular block (94%) without requiring general anesthesia or the risk of ventricular dysfunction or cardiac perforation. The large-tip electrode allows a threefold increase in delivered power and markedly decreases the number of pulses and time required to produce atrioventricular block.
Circulation, 1991
Background. Two catheter electrode systems were compared for delivering radiofrequency current for ablation of the atrioventricular junction. Seventeen patients with drug-resistant supraventricular tachyarrhythmias were studied. Methods and Results. A 6F or 7F catheter with six or eight standard electrodes (1.25 mm wide, 2.5-mm spacing) was used in the first seven patients (group 1). A 7F quadripolar catheter with a large-tip electrode (4 mm long; surface area, 27 mm2) was used in the final 10 patients (group 2). Both ablation catheters were positioned to record a large atrial potential and a small but sharp His bundle potential from the distal bipolar electrode pair. Radiofrequency current was applied between a large skin electrode on the left posterior chest and either 1) each individual electrode on the standard-tip electrode catheter at 40 V (group 1) or 2) the large-tip electrode at 50-60 V (group 2). Radiofrequency current was limited to 40 V in group patients because of the strong potential for an early impedance rise when higher voltage is applied through standard electrodes. Complete atrioventricular block was achieved in six of seven group 1 patients and all 10 group 2 patients. A junctional escape rhythm followed ablation in five or six group 1 patients (mean cycle length, 1,066±162 msec) and eight of 10 group 2 patients (mean cycle length, 1,281±231 msec). Atrioventricular block was produced in a mean of 4.7±4.6 radiofrequency current applications delivered over a period of 42+±45 minutes using the large-tip electrode (group 2) compared with 46±22 applications using standard electrodes (15.9±10.2 applications delivered through the standard-tip electrode) over a period of 147±59 minutes (group 1). For the application producing atrioventricular block, the large-tip electrode used higher voltage (58±17 versus 38+5 V, p <0.03) and had lower impedance (103±22 versus 148+40Qk, p <0.01), resulting in greater power (33.0±13.0 versus 10.2 ±0.6 W, p <0.003) and shorter time to block (8±3 versus 22±3 seconds, p <0.001). Current delivery through standard electrodes was limited by an impedance rise occurring 7±7 seconds after the onset of one or more radiofrequency current applications at 10±1 W in six of seven patients. Using the large-tip electrode, an impedance rise occurred in five of 10 patients, but at 25±10 W and after 21±9 seconds. Atrioventricular block occurred before the impedance rise in three of these five patients. Complete atrioventricular block persisted in 15 of 16 patients at a mean follow-up of 8.7 months. Atrioventricular conduction returned at 1 month in one group 2 patient and was successfully ablated by a second procedure. Three group 1 patients died 0.5-2 months after ablation, and a fourth patient underwent cardiac transplantation after 10 months. Pathological examination of the heart in two of these patients showed necrosis of the atrioventricular node and origin of the His bundle, without injury to the middle or distal His bundle. All 10 group 2 patients are alive and subjectively improved after ablation. Conclusions. We conclude that catheter-delivered radiofrequency current effectively produces complete atrioventricular block (94%) without requiring general anesthesia or the risk of ventricular dysfunction or cardiac perforation. The large-tip electrode allows a threefold increase in delivered power and markedly decreases the number of pulses and time required to produce atrioventricular block.
Circulation. Arrhythmia and electrophysiology, 2015
Background-Cardiac resynchronization therapy (CRT) delivered via left ventricular (LV) endocardial pacing (ENDO-CRT) is associated with improved acute hemodynamic response compared with LV epicardial pacing (EPI-CRT). The role of cardiac anatomy and physiology in this improved response remains controversial. We used computational electrophysiological models to quantify the role of cardiac geometry, tissue anisotropy, and the presence of fast endocardial conduction on myocardial activation during ENDO-CRT and EPI-CRT. Methods and Results-Cardiac activation was simulated using the monodomain tissue excitation model in 2-dimensional (2D) canine and human and 3D canine biventricular models. The latest activation times (LATs) for LV endocardial and biventricular epicardial tissue were calculated (LVLAT and TLAT), as well the percentage decrease in LATs for endocardial (en) versus epicardial (ep) LV pacing (defined as %dLV=100×(LVLAT ep −LVLAT en)/LVLAT ep and %dT=100×(TLAT ep −TLAT en)/TLAT ep , respectively). Normal canine cardiac anatomy is responsible for %dLV and %dT values of 7.4% and 5.5%, respectively. Concentric and eccentric remodeled anatomies resulted in %dT values of 15.6% and 1.3%, respectively. The 3D biventricular-paced canine model resulted in %dLV and %dT values of −7.1% and 1.5%, in contrast to the experimental observations of 16% and 11%, respectively. Adding fast endocardial conduction to this model altered %dLV and %dT to 13.1% and 10.1%, respectively. Conclusions-Our results provide a physiological explanation for improved response to ENDO-CRT. We predict that patients with viable fast-conducting endocardial tissue or distal Purkinje network or both, as well as concentric remodeling, are more likely to benefit from reduced ATs and increased synchrony arising from endocardial pacing.
Long-term pacemaker dependency after radiofrequency ablation of the atrioventricular junction
American Heart Journal, 1997
This prospective study was conducted to determine the percentage of patients with long-term pacemaker dependency aftersuccessful radiofrequency ablation of the atrioventricular junction. Abrupt inhibition of the pacemaker was performed 13.5 ± 8.1 months after ablation in 59 patients. A ->5-second asystole was considered to indicate pacemaker dependency. Pacemaker dependency was present in 18 patients. Absence of escape rhythm immediately after ablation was strongly associated with a higher incidence of longterm pacemaker dependency. The following variables were not associated with pacemaker dependency: age, presence of cardiac disease, presence of preablation bundle branch block, number of radiofrequency applications, a bilateral approach for ablation, and continuation of antiarrhythmic therapy after ablation. We concluded that (1) long-term pacemaker dependency is present in 30.5% of the patients after successful atrioventricular junction radiofrequency ablation and (2) absence of escape rhythm immediately after ablation predicts long-term pacemaker dependency. (Am Heart J 1997;133:580-4.)
European Heart Journal, 2018
Cardiac resynchronisation therapy: selection and implantation / Catheter ablation 1217 Results: The relationship between electrical dyssynchrony (79±27ms) and mechanical dyssynchrony (150±40ms) is highly statistically significant (p<0,000001) while the QRS duration (164±15ms) does not show any statistical significance to mechanical dyssynchrony. Example of comparison between electrical depolarization and mechanical activation of LV myocardium in LBBB patient is shown in Figure 1. Conclusion: The dyssynchrony of electrical depolarization distribution over V leads is comparably similar to mechanical activation of myocardium. The electrical myocardial dyssynchrony can be numerically assessed with units of ms precision. Better temporal and spatial resolution of used higher density ECG allows for easy and accurate assessment of electrical depolarization of ventricles. This simple and cheap method could be used for more precise diagnostics of LBBB and thus more proper selection of CRT recipients and also possibly CRT setting optimization. Funding Acknowledgements: Supported by the project no. LQ1605 from the National Program of Sustainability II (MEYS CR). P5743 Effect of lower interatrial septal pacing on atrial hemodynamic function and mechanical synchrony in patient with cardiac resynchronization therapy and abnormal interatrial delay