Arrhythmogenic Phenotype in Dilated Cardiomyopathy: Natural History and Predictors of Life‐Threatening Arrhythmias

Abstract

Background

Patients with dilated cardiomyopathy ( DCM) may present with ventricular arrhythmias early in the disease course, unrelated to the severity of left ventricular dysfunction. These patients may be classified as having an arrhythmogenic DCM ( AR‐ DCM). We investigated the phenotype and natural history of patients with AR‐ DCM.

Methods and Results

Two hundred eighty‐five patients with a recent diagnosis of DCM (median duration of the disease 1 month, range 0 to 7 months) and who had Holter monitoring at baseline were comprehensively evaluated and followed for 107 months (range 29 to 170 months). AR‐ DCM was defined by the presence of ≥1 of the following: unexplained syncope, rapid nonsustained ventricular tachycardia (≥5 beats, ≥150 bpm), ≥1000 premature ventricular contractions/24 hours, and ≥50 ventricular couplets/24 hours, in the absence of overt heart failure. The primary end points were sudden cardiac death ( SCD), sustained ventricular tachycardia ( SVT), or ventricular fibrillation ( VF). The secondary end points were death from congestive heart failure or heart transplantation. Of the 285 patients, 109 (38.2%) met criteria for AR‐ DCM phenotype. AR‐ DCM subjects had a higher incidence of SCD/ SVT/ VF compared with non– AR‐ DCM patients (30.3% vs 17.6%, P=0.022), with no difference in the secondary end points. A family history of SCD/ SVT/ VF and the AR‐ DCM phenotype were statistically significant and cumulative predictors of SCD/ SVT/ VF.

Conclusions

One‐third of DCM patients may have an arrhythmogenic phenotype associated with increased risk of arrhythmias during follow‐up. A family history of ventricular arrhythmias in DCM predicts a poor prognosis and increased risk of SCD.