Arrhythmic indicators of adverse cardiovascular prognosis—Bridging the gap between myocardial electrical and structural dysfunction

Abstract

The association between the development of ventricular arrhythmias and the adverse clinical outcome has been well established, particularly the relationship between spontaneously occurring ventricular tachycardia/ventricular fibrillation (VT/VF) and sudden arrhythmic death. The earliest reports in the literature were devoted to confirming this relationship, with attention being gradually directed toward evaluation of interventions at preventing arrhythmic death. Some have clearly shown benefit (implantable cardioverterdefibrillator), while others have not been met with similar success (antiarrhythmic medications). More recently, efforts have focused on limiting the occurrence of VT/VF, with the most exciting results arguably being demonstrated through catheter ablation. The approaches and patient selection for such therapies have similarly evolved, with original reports describing mapping and surgical ablation in survivors of myocardial infarction, followed by endocardial catheter ablation in such patients. With establishment of its efficacy in such populations, interest has widened to include its application in those with VT in the context of nonischemic substrates. The implications of such discoveries are clearly apparent: the development of adjunctive therapies for ventricular arrhythmias recalcitrant to more conservative measures, largely for palliative purposes. Recent data further support the use of catheter ablation in individuals with frequent ventricular arrhythmias/ectopy, with the goal of improving associated nonischemic cardiomyopathy. Hence, with advances in knowledge and technology, catheter ablation in select individuals has progressed to the realm of offering not only symptomatic but also prognostic benefit. Spontaneously occurring VT/VF and ventricular dysfunction, well-established predictors of adverse clinical outcome, are often coexisting features in a growing number of patients presenting to the electrophysiology laboratory. This raises the question: Is there further prognostic information that can