Unusual Incessant Ventricular Tachycardia

Abstract

V entricular tachycardia (VT) is defined as a tachycardia with a rate of >100 per minute, with ≥3 consecutive beats that originates from the ventricles, and is independent of atria or atrioventricular nodal conduction. Of all the VTs, 10% occurs in those with structurally normal heart and these are called as idiopathic VTs, and the rest 90% occurs in patients with structural heart disease. VTs may be classsified based on the clinical characteristic (clinical VT, hemodynamically stable or unstable, repetitive, incessant, etc.), morphology (monomorphic, multiple morphologies, pleomorphic, polymorphic, bidirectional, etc.) or mechanisms (scar-related reentry, automaticity, and triggered activity). Incessant VT is defined as continuous sustained VT during several hours, which recurs promptly despite repeated intervention for termination. VT storm is considered as ≥3 separate episodes of sustained VT within 24 hours, each requiring termination by an intervention. Monomorphic VT has a uniformly similar QRS configuration from beat-to-beat, with either right or left bundle configuration depending on whether the dominant deflection in lead V1 is R or S wave. Multiple monomorphic VTs refer to >1 morphologically distinct monomorphic VT, occurring as different episodes, or induced at different times. Polymorphic VT has continuously changing QRS configuration from beat-to-beat indicating a changing ventricular activation sequence. Pleomorphic VT has >1 morphologically distinct QRS complex occurring during the same episode of VT, but the QRS is not continuously changing. Bidirectional VT (BVT) is characterized by beat-to-beat alternation of the QRS axis on the ECG and is usually regular. Editor's Perspective see p 1512Here, we describe unusual incessant VT in a young male and discuss evaluation, management, and the possible mechanism. Case ReportA 33-year-old male, nondiabetic, nonhypertensive, presented with history of palpitation, chest discomfort, and fatigue of 6 hours duration. He had been otherwise healthy, not on any medications with no history of tobacco, alcohol, or drug use. At presentation, pulse rate was 144 beats per minute, irregular, blood pressure 96/60 mm Hg, and the rest of physical examination was unremarkable. Twelve-lead ECG revealed a wide complex regularly irregular tachycardia at a rate of 144 beats per minute, right bundle morphology, QRS duration of 200 to 220 ms, QRS axis alternating between +160° and −40°, QRS transition alternating from V3 to V6, and evidence of atrioventricular dissociation (Figure 1). Tachycardia was unresponsive to intravenous lignocaine, esmolol, amiodarone (300 mg during 1 hour), and 2 attempts of biphasic direct current (DC) cardioversion of 200 J. Because the tachycardia was incessant, patient was sedated, intubated, ventilated, and continued on intravenous amiodarone (900 mg/24 hours) with further 4 unsuccessful attempts at DC cardioversion. Tachycardia converted to monomorphic VT with occasional VT complexes of the 2nd morphology (Figure 2), which terminated 6 hours late...

Implantable cardioverter defibrillator for the prevention of sudden cardiac death: Systematic review and pooled analysis

“…Exercise shortens the QT interval less than observed in normal patients with drug-induced torsades de pointes of the LQT syndrome. Torsades de pointed occurs more often in patients with depressed LV systolic function [30].…”

Reciprocating Reentry

“…1 Here, it is not the exit or subsequent propagation of an event that produces the changes in interval or morphology but rather the influence of one focus on another. In this ping-pong type of abruptly changing directionality, one site's threshold for triggered activity produces in turn an increased rate that then allows another site to reach its threshold for a delayed afterdepolarization and may thus initiate and maintain a pattern of marked change in access or morphology during a sustained arrhythmia.…”

“…1 First, as with bedside demonstration of a physical sign, we have a unique ECG that compels the electrophysiology student to explain a clearly documented event that we may not have otherwise imagined possible-a wide complex, bidirectional, otherwise stable, ventricular tachycardia (VT). Then, the author briefly historically reviews important definitions with regard to VT morphology and subsequently provides an insightful analysis of possible mechanisms and the relationship of this arrhythmia to a distinct underlying pathological substrate.…”

Management of monomorphic ventricular tachycardia electrical storm in structural heart disease

“…It is classified based on hemodynamic stability, duration (nonsustained if <30 seconds and sustained if >30 seconds or requiring termination due to hemodynamic compromise in <30 seconds), morphology (monomorphic or polymorphic, etc.) or mechanism (scar-related re-entry, automaticity, and triggered activity) [2]. Of all the VTs, 10% occurs in those with structurally normal heart and these are referred to as idiopathic VTs, and the remaining 90% occurs in patients with structural heart disease [2].…”

“…or mechanism (scar-related re-entry, automaticity, and triggered activity) [2]. Of all the VTs, 10% occurs in those with structurally normal heart and these are referred to as idiopathic VTs, and the remaining 90% occurs in patients with structural heart disease [2]. Incessant VT is defined as hemodynamically stable VT which persists for longer than 12 hours [3] ES in those without ICD is referred to three or more sustained VT or ventricular fibrillation (VF) occurring within 24 hours [1], [4].…”