Intermittent Atrial Undersensing in Single-Lead VDD Pacemakers in Patients With Bradycardia-Sensitive Repolarization: A Possible Mechanism for Ventricular Arrhythmia (original) (raw)
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Journal of Cardiovascular Electrophysiology, 2018
A 49-year-old man with a complex congenital heart disease (comprising dextrocardia with situs solitus, atrial septal defect, ventricular septal defect, severe pulmonary stenosis and D-transposition of the great arteries surgically repaired by means of the Rastelli procedure at the age of 22 years) underwent single-chamber defibrillator (ICD) implantation for primary prevention of sudden cardiac death due to severe systolic dysfunction of the systemic ventricle. The right ventricular lead (RV; Durata 7120, St. Jude Medical TM, Sylmar, CA, US) was implanted using a conventional transvenous approach. Two years later the patient developed heart failure symptoms and the ECG showed sinus rhythm with first degree AV block and left bundle branch block QRS morphology. Therefore, upgrade to cardiac resynchronization therapy (Unify 3235-40Q CRT-D, St Jude Medical TM, Sylmar, CA, US) was performed in 2012. Two epicardial leads were surgically implanted in the left atrium (LA; Miopore 511212, Greatbatch medical TM) and left ventricle (LV; 6071, Medtronic TM, Minneapolis, US). The X-ray lead positioning is shown in Figures 1A and 1B. The patient was followed by remote monitoring. Pacing and sensing parameters were stable (R wave 5.5 mV, RV threshold 1.0V at 0.5 ms; P wave 3.1 mV, LA threshold 0.75V at 0.5 ms; LV threshold: 1.75V at 0.5 ms) and no arrhythmic episodes were documented during the follow-up. The real time EGM showed a significant far-field of the ventricular signal in the atrial channel, as consequence of proximity of epicardial lead. The ventricular far-field falls in the blanking period,
Pacemaker‐mediated arrhythmias
Journal of Arrhythmia
Pacemakers can be directly involved in initiating or sustaining different forms of arrhythmia. These can cause symptoms such as dyspnea, palpitations, and decompensated heart failure. Early detection of these arrhythmias and optimal pacemaker programming is pivotal. The aim of this review article is to summarize the different types of pacemaker-mediated arrhythmias, their predisposing factors, and mechanisms of prevention or termination. K E Y W O R D S endless loop tachycardia, pacemaker-mediated arrhythmia, retrograde ventriculo-atrial conduction This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
Isoelectric Atrioventricular Interval during DDD Pacing: What is the Mechanism?
Pacing and Clinical Electrophysiology, 2011
A 72-year-old woman was admitted for an electrophysiology study and pacemaker checkup. A DDD pacemaker (Actros DR, Biotronik, Berlin, Germany) had been implanted 4 years prior at another institution to treat tachy-brady syndrome (sinus bradycardia plus paroxysmal atypical atrial flutter). She had neither history of cardiac surgery nor antiarrhythmic drug use and no electrolyte abnormalites were detected. The electrocardiogram (ECG) during DDD pacing showed an isoelectric interval, but no trace of atrial depolarization after an atrial pacing spike in any of the 12 ECG leads. This finding strongly suggested atrial noncapture . Increasing the atrial-pacing amplitude up to a maximum output of 8.4 V did not affect the atrioventricular (AV) interval morphology. An atrial-intracardiac electrogram obtained during the electrophysiology study showed apparent retrograde atrial depolarization at the end of each QRS complex, which is often observed in cases of atrial noncapture . However, considering the tracing from the lower panel of , is a diagnosis of atrial noncapture correct?
Journal of the American College of Cardiology, 1983
A case of recurrent ventricular tachycardia produced by an asynchronous ventricular stimulus of a normally functioning "committed" atrioventricular (AV) sequential demand (DVI) pacemaker is described. The characteristics of these units are compared with those of the A variety of pacemaker-induced arrhythmias has been observed with the introduction of new cardiac pacing modes (1). With the advent of atrioventricular (AV) sequential demand (DVI) pacemakers, the electrocardiographic features associated with their normal operation have been studied and reported (2). In this report, we describe an abnormal event: the induction of ventricular tachycardia by a normally functioning DVI pacemaker.
Pacemaker induced torsades de pointes tachycardia
Heart, 1998
Objective-To assess the stability and reproducibility of computerised QT dispersion (QTd) measurement in healthy subjects, as this is presently being incorporated into commercial electrocardiographic systems. Methods-70 healthy volunteers (mean (SD) age 38 (10) years, 35 men, 35 women) with a normal 12 lead electrocardiogram (ECG) were studied. From each subject, 70 ECG recordings were taken using the MAC VU ECG recorder (Marquette). In study A, 50 ECGs were recorded in each subject: 10 supine, 10 sitting, 10 standing, 10 holding breath in maximum inspiration, and 10 holding breath in maximum expiration. After a mean interval of 8 (3) days (range 7 to 23), 10 recordings in supine and 10 in the standing position were repeated in each subject (study B). On measurements made using a research version of the commercial software without manual modification, the reproducibility of QTd was assessed by coeYcient of variance (CV) and relative error, and comparisons made with other ECG indices. Results-(1) QTd measurements were stable and not influenced by changes in posture and respiratory cycle; (2) there was no diVerence in QTd measurements between men and women, or between age groups dichotomised at 35 years; (3) no correlation was found between QTd and heart rate or QT interval; (4) short term reproducibility of all QTd measurements (CV 15.6% to 43.8%) was worse than that of conventional ECG indices (CV 1.4% to 5.3%); (5) long term reproducibility of QTd measurements (relative error 27.4% to 31.0%) was also worse than that of conventional ECG indices (relative error 1.8% to 7.9%) (p < 0.0001); (6) the reproducibility of QTd measurements tended to increase when several serial recordings were averaged. Conclusions-Computerised measurements of global QTd and global QT-SD from 12 lead ECG by the MAC VU/QT Guard system are not significantly altered by changes in posture and respiration. The reproducibility of all QTd measurements is inferior to that of conventional ECG indices in healthy subjects.
Usefulness of Echocardiography to Predict Inappropriate Atrial Sensing in Single-Lead VDD Pacing
Pacing and Clinical Electrophysiology, 1999
DE COCK, C.C., ET AL.: Usefulness of Echocardiography to Predict Inappropriate Atrial Sensing in Single-Lead VDD Pacing. Reliable atrial sensing is the prerequisite for restoration of atrioventricular synchrony in patients with single-lead VDD pacing systems. To determine echocardiographic variables associated with inappropriate atrial sensing, 21 consecutive patients with symptomatic second-or third-degree AV block and normal sinus node function were studied. Prior to implantation echocardiographic measurements of end-systolic and end-diastolic dimensions and volunws of the right atrium and right ventricle were performed. All patients underwent implantation of a Medtronic Thera VDD(d) pacemaker with a bipolar Medtronic Capsure electrode. A minimal amplitude of the unfiltered atrial electrocardiogram of ^ 0.5 mV was required for permanent lead position and the atrial sensitivity was programmed below the lowest recorded value. Appropriate atrial sensing (atrial triggered ventricular paced complexes/total number of ventricular paced complexes) was assessed during 24-hour Holter monitoring and treadmill exercise testing 3 to 6 weeks after implantation. Inappropriate atrial sensing (< 95% correct atrial synchronization during Holter registration and/or < 97.5% during exercise testing) was present in nine patients. Right atrial volumes and the right ventricular end-diastolic volume was significantly higher, as compared to patients without inappropriate sensing (12 patients). The right atrial and diastolic volumes had the highest correlation with correct atrial sensing r = 0.83, P < 0.0001). Using a postdefined cut-off value of > 80 mL for the end-diastolic right atrial volume, sensitivity and specificity for inappropriate sensing was 100% and 92%, respectively. These findings show that preimplant echocardiography can identify patients with inappropriate sensing during VDD pacing, in whom DDD pacing should be considered. (PACE 1999(PACE : 22:1344(PACE -2347 VDD pacing, atrial sensing, echocardiography
Predictors of loss of atrioventricular synchrony in single lead VDD pacing
Heart, 1998
Objective-To evaluate maintenance of proper VDD function, defined as persistence of sinus rhythm with atrial synchronous ventricular pacing, and to define factors predicting failure of the VDD mode in patients with atrioventricular (AV) block and normal sinus function. Design-Observational study in 86 consecutive patients (mean (SD) age 74 (12) years; 38 women, 48 men) with single lead VDD pacing systems (Intermedics Unity, n = 66, Medtronic Thera VDD, n = 20), implanted for high degree AV block with documented normal sinus node. Pacemaker function was assessed by event counters, telemetric measurements, and Holter recordings. Demographic, radiological, and pacing variables were correlated with loss of proper VDD function. Results-During a mean (SD) follow up of 10 (10) months (range 1-37), sinus rhythm and atrial triggered ventricular pacing were maintained in 70 of 86 patients (81%). Atrial undersensing was observed in nine patients, lead migration in two, atrial fibrillation in three, and symptomatic sinus bradycardia in two. Univariate predictors of loss of proper VDD function were: low position of the atrial dipole relative to the carina (> 6 cm; p < 0.01) during fluoroscopy; and maximum programmable atrial sensitivity of the pacemaker (p = 0.03). In a multivariate analysis, only dipole position remained predictive of outcome (p < 0.02). Not predictive were sex, age, symptoms before pacemaker implantation, cardiothoracic ratio or dilatation of individual heart chambers on chest x ray, side of device implant, and P wave amplitude at implant. Conclusions-To maintain proper VDD function in the long term, a low anatomical dipole position relative to the carina should be avoided. Electrical guidance of dipole positioning does not seem to influence long term outcome.
Pacemaker-mediated tachycardia with varying cycle length: what is the mechanism?
Europace, 2009
Two months before the ablation procedure, the patient underwent a 16-slice spiral computed tomography (CT), which showed a typical pattern of dextrocardia as depicted in . In addition, the CT images were essential to understand the patient's anatomy: as shown in , the pulmonary veins (PVs) had a common trunk on the right side of the morphological left atrium and there were two separate pulmonary veins with early branching on the left side of the morphological left atrium.
Heart, 1987
The relation between the occurrence of repolarisation abnormalities after right ventricular pacing and spontaneous arrhythmias was investigated in 16 patients in whom the sick sinus syndrome was suspected. All patients had normal QRS complexes and T waves in the electrocardiogram before pacing and required atrial stimulation and His bundle recording for diagnostic purposes. Patients were randomised into a study group or a control group. In the eight patients in the study group right ventricular pacing was performed for 12 hours, and was followed by inversion of the T wave in surface leads II, III, aVF, and V2-V5 and lengthening of the QTc interval. The frequency and complexity of ventricular arrhythmias increased after pacing in six patients who had ventricular extrasystoles in the baseline Holter recording. As the configuration of the T wave became normal the frequency of ventricular extrasystoles returned to baseline values. In the control group of eight patients ventricular pacing was not performed after the electrophysiological study and no changes were seen in T wave configuration and in the frequency of spontaneous arrhythmias.