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Barold S.S.,Florida Heart Rhythm Institute | Kucher A.,Biotronik
PACE - Pacing and Clinical Electrophysiology | Year: 2014

Some devices used for cardiac resynchronization therapy (CRT) can sense from the left ventricular (LV) lead as in Biotronik CRT devices (Biotronik GmbH, Berlin, Germany), whose special LV timing cycles form the basis of this report. LV sensing (LVs) was designed to prevent competitive pacing outside the LV myocardial absolute refractory period. LVs works by inhibiting the release of an LV pacemaker stimulus (LVp) in the vulnerable period of the LV during a programmable period. LVs with stored LV electrograms may also provide recordings of diagnostic value in tachyarrhythmias. LVs has added a new dimension to the evaluation of the function of CRT devices, because it is manifested by unfamiliar timing cycles. In this respect, Biotronik devices can initiate an LV upper rate interval (URI) upon sensing a right-sided event when LVs is turned off. An inhibited LVp can also initiate an LVURI. The LVURI should generally be programmed to a relatively short duration and shorter than the right ventricular URI to prevent a special form of desynchronization arrhythmia sustained by LVs. This arrhythmia is characterized by recurring delayed LVs events in sequences associated with RV pacing followed by LVs events with loss of LVp. © 2014 Wiley Periodicals, Inc.

Barold S.S.,Florida Heart Rhythm Institute | Stroobandt R.X.,Ghent University
Europace | Year: 2012

This report describes the de novo occurrence of pacemaker-mediated tachycardia (PMT) in a patient with a dual-chamber implantable cardioverter-defibrillator and stable retrograde ventriculoatrial conduction time. The same rate-adaptive post-ventricular atrial refractory period (PVARP) duration had previously prevented PMT. Oversensing of atrial false signals from a defective lead shortened the PVARP with consequent sensing of retrograde conduction. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2012.2012 © Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2012.

Barold S.S.,Florida Heart Rhythm Institute | Stroobandt R.X.,Ghent University
Journal of Electrocardiology | Year: 2012

We report the initiation of pacemaker-mediated tachycardia by a St Jude implantable cardioverter-defibrillator with a programmed Ventricular Intrinsic Preference algorithm used for minimizing or inhibiting right ventricular pacing. This feature prolongs the atrioventricular (AV) delay periodically to determine if ventricular sensed events follow atrial events. Retrograde ventriculoatrial conduction and pacemaker-mediated tachycardia were initiated by long extended AV delays of 300 and 400 milliseconds. The 400-millisecond AV delay consisted of the programmed sensed AV delay (100 milliseconds) plus the Ventricular Intrinsic Preference increment (200 milliseconds) plus 100 milliseconds imposed by the AutoCapture algorithm when it detected loss of ventricular capture. © 2012 Elsevier Inc. All rights reserved.

Zanon F.,Electrophysiology Unit | Barold S.S.,Florida Heart Rhythm Institute
Annals of Noninvasive Electrocardiology | Year: 2012

The success rate of direct His bundle pacing (DHBP) and paraHisian pacing has improved remarkably in the last 3-5 years with the advent of dedicated fixation systems that have reduced procedural duration, dislodgement rate, and fluoroscopy time. The methodology of DBHP remains still more complex than paraHisian pacing and is associated with high-pacing thresholds. Thus, DHBP entails greater battery current drain and reduced device longevity. A shift toward paraHisian pacing (which is fusion pacing of myocardium and His bundle) has occurred because its implementation is easier and the electrical parameters are superior to those of DBHP. Currently, an additional safety lead is inserted at the RV apex or outflow tract to prevent asystole, especially in patients with pure DHBP. It is often possible to avoid a safety lead with paraHisian pacing because ventricular pacing is virtually assured on a long-term basis via myocardial capture. DBHP and paraHisian pacing can be achieved in a substantial proportion of patients with varying grades of narrow QRS AV block or after AV junctional ablation and in some patients with the ECG manifestation of bundle branch block caused by an intraHisian lesion. Preliminary observations suggest that DHBP may be useful in some patients requiring cardiac resynchronization if it produces a narrow QRS complex because the site of an intraHisian lesion responsible for left bundle branch block is above the site of DHBP. © 2012, Wiley Periodicals, Inc.

Barold S.S.,Florida Heart Rhythm Institute | Israel C.W.,Klinik fur Innere MedizinKardiologie
Herzschrittmachertherapie und Elektrophysiologie | Year: 2015

A number of trials have shown that irrespective of baseline QRS duration, left ventricular (LV) dysfunction and heart failure are more common in patients with right ventricular (RV) than in those with biventricular (BiV) pacing. By contrast, preliminary results of the BIOPACE trial (follow-up 5.6 years) yielded a disappointing comparison of RV vs. BiV pacing. Pacemaker-induced cardiomyopathy (PIC) may occur in patients with normal and abnormal LV ejection fractions (LVEF) and tends to occur if there is RV pacing more than 40 % of the time. Yet, some pacemaker-dependent patients do not develop LV dysfunction. PIC can be improved in about two thirds of patients by upgrading to a BiV system and the results are comparable to de novo BiV pacing in patients with a wide QRS complex. The findings of the BLOCK HF trial (2013) suggested that patients requiring pacing virtually 100 % of the time might benefit from BiV pacing irrespective of the LVEF (< 50 %), manifestations of heart failure, QRS duration, or functional class. These characteristics would generate many patients for BiV pacing. However, these recommendations should now be weighed against a more conservative approach based on the recently announced results of the BIOPACE trial. Organizational guidelines recommend BiV pacing for bradycardia irrespective of QRS duration for patients with LVEF < 35 %. At this time, BiV pacing for antibradycardia therapy (irrespective of QRS duration) has to be individualized in the setting of a normal or decreased LVEF (> 35 %) and according to the expected percentage of RV pacing. The benefit of BiV pacing should be considered against procedural complications, which are more frequent than with traditional RV pacing. © 2014, Springer-Verlag Berlin Heidelberg.

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