Importance of Initiation Pattern of Polymorphic Ventricular Tachycardia in Patients with Implantable Cardioverter Defibrillators

Abstract

The stored ICEGs demonstrate that PVT is most often preceded by ventricular ectopy. To be reverted, nonsudden onset episodes require higher levels of shock energy and more frequently multiple shock achievements than sudden onset episodes.

Mode of onset of polymorphic ventricular tachycardia in acute myocardial infarction

“…Our findings of a shorter PI of the first beat that initiates the arrhythmia and slower heart rate preceding PVTs of nonsudden onset are in accordance with a previous study (22) on characteristics of PVT initiation in patients who underwent ICD implantation. Taylor et al (20) demonstrated that PVTs, in comparison with MVTs, had shorter PIs and were preceded by bradycardia, postulating that the triggered mechanism may be responsible for a shorter PI in PVTs.…”

“…Most studies described patterns of monomorphic VT onset in patients with coronary artery disease, Chagas disease and ischemic or nonischemic cardiomyopathy with an ICD (2)(3)(4)(19)(20)(21)(22). Our study complements the results of previous reports by characterizing patterns of PVT initiation early after acute MI.…”

“…Clinical and electrophysiological features, such as left ventricular dysfunction and faster heart rate of PVT, in patients with acute MI resemble the characteristics of VTs reported in other patient populations, regardless of VT morphology (3)(4)(19)(20)(21)(22). Patients with nonsudden-onset PVT had lower ejection fractions, which can be attributed to the fact that left ventricular dysfunction may serve as a substrate for arrhythmia.…”

“…Two main patterns of VT onset have been reported: nonsudden-onset tachycardia -initiated by late-coupled ventricular ectopic beats with a short-long-short cycleand sudden-onset tachycardia (19)(20)(21)(22). The frequency of so-called nonsudden-onset VT has been reported to be 56% to 85% (19)(20)(21)(22). Ventricular fibrillation episodes were initiated by either ventricular premature beats or a short-long-short cycle (23).…”

Ventricular Tachyarrhythmias in Implantable Cardioverter Defibrillator Recipients: Differences Between Ischemic and Dilated Cardiomyopathies

“…Eventually, at the end of the nineties, it has been shown that coronary artery disease (CAD) and dilated cardiomyopathy (DCM) underlie different mechanisms of spontaneous and induced VT [Pogwizd et al 1998, Chung et al 1997; moreover ,differences in spontaneous VT from ICD recipients began to be investigated. Indeed, since the early 2000, various studies have analyzed intracardiac electrograms (EGMs) and initiation VT pattern [Gorenek et al 2006, Taylor et al 2000, Saeed et al 2000, while others have investigated circadian distribution [Carson et al 2000, Englund et al 1999, Eksik et al 2007, Taneda et al 2001] of spontaneous VT in ICD patients. Some of these studies [Taylor et al 2000, Saeed et al 2000, Englund et al 1999] have failed to detect differences in both the patterns of initiation and in EGMs between patients with different etiologies of heart disease.…”