Ventricular arrhythmias in nonischemic cardiomyopathy

Abstract

Nonischemic cardiomyopathies (NICMs) are composed of variable disease entities, including primary and secondary cardiomyopathies. Determining the etiology of NICM provides pivotal roles of not only the understanding of the individual pathogenesis, but also the clinical management, such as risk stratification, pharmacological treatment, and intervention therapies. Despite the diverse causes of NICM, these cases mostly require clinical attention owing to progressive myocardial injury, resulting in ventricular dysfunction and heart failure. The interaction between the diseased ventricular substrates and systemic/neurophysiological factors contributes to the cornerstones responsible for ventricular arrhythmogenesis and sudden cardiac death (SCD). Prevention of SCD and diminishing ventricular tachyarrhythmias are the important mainstays for the management of NICM patients. Given the understanding of the abnormal ventricular substrates and advancement of navigation systems, radiofrequency catheter ablation (RFCA) has become an adjunctive or alternative strategy for NICM patients who experience drug‐refractory ventricular tachycardias (VTs). Successful ablation can frequently be achieved at the expense of an epicardial intervention. A recent study has proven the survival benefits for NICM patients who are free from recurrent VTs after a successful RFCA, regardless of the New York Heart Association (NYHA) functional class status or left ventricular ejection fraction. Additionally, recent evidence has highlighted the better delineation of a diseased myocardium through the incorporation of cardiovascular magnetic resonance imaging (CMRI) and 3D mapping systems, which can facilitate the identification of critical ventricular arrhythmogenic substrates in NICM patients.

Cardiac magnetic resonance predicts ventricular arrhythmias in scleroderma: the Scleroderma Arrhythmia Clinical Utility Study (SAnCtUS)

“…Cardiovascular magnetic resonance (CMR) offers considerable additional utility beyond LVEF in SSc by allowing the identification of myocardial oedema and fibrosis [ 18 , 19 ], as myocardial fibrosis is the most common substrate for re-entrant arrhythmias [ 20 ]. CMR can thus potentially translate 24 h Holter findings to distinguishable structural myocardial abnormalities functioning as arrhythmogenic foci, as myocardial fibrosis identified by CMR is the most common arrhythmogenic substrate specifically in non-ischaemic cardiomyopathies [ 21 , 22 ], and larger scar extents are associated with increased risk of inducible VT or SCD [ 22 ]. We hypothesized that CMR indices would be independently associated with the occurrence of rhythm disturbances and SCD in SSc patients.…”

Characteristics and outcomes of ventricular tachycardia and premature ventricular contractions ablation in patients with prior mitral valve surgery

“…We also found that MVS patients with a history of CAD showed a trend of better VA recurrence‐free survival compared with those without CAD history (Figure 2B). This could be related to the previously reported different nature of VT circuits between ICM and NICM 43,44 . One observational study compared the characteristics and the outcomes of VT ablation between ICM and NICM patients has shown that complete success and 1‐year VT‐free survival were higher in the ICM group 44 .…”

Characteristics and Outcomes of Ventricular Tachycardia and Premature Ventricular Contractions Ablation in Patients with Prior Mitral Valve Surgery

“…(Figure 2B ) This could be related to the previously reported different nature of VT circuits between ICM and NICM. 43,44 One observational study compared the characteristics and the outcomes of VT ablation between ICM and NICM patients has shown that complete success and 1-year VT-free survival were higher in the ICM group. 44 The critical isthmus for VT was identified with endocardial entrainment in 62% of the ICM group and in 17% of the NICM group.…”