Arrhythmic Event Risk High in Early Phase of Dilated Cardiomyopathy

Patients with dilated cardiomyopathy have a significant risk of major arrhythmic events, even in the early stages of disease, according to research published in JACC: Clinical Electrophysiology.

Pasquale Losurdo, MD, of University Hospital “Ospedali Riuniti” in Trieste, Italy, and colleagues studied 952 patients with dilated cardiomyopathy who were included in the Heart Muscle Disease Registry of Trieste from 1988 to 2014. They were interested in determining prevalence, characterization, and possible indicators of early sudden cardiac death/malignant ventricular arrhythmias.

Of the total population, 20 patients experienced sudden cardiac death/malignant ventricular arrhythmias within the first 6 months of enrollment, which was the primary end point. Compared to patients without early sudden cardiac death/malignant ventricular arrhythmias, these patients had a worse NYHA functional class (NYHA III-IV 42% vs 22%; P=.038), a longer QRS complex duration (127 ± 41 msec vs 108 ± 33 msec; P=.013), and a larger indexed left ventricular end-systolic volume (LVESVI; 82 ± 49 mL/m² vs 67 ± 34 mL/m²; P=.049).

In addition, beta-blockers were not as well tolerated in patients who did not experience early sudden cardiac death/malignant ventricular arrhythmias (59% vs 83%; P=.008), which the researchers attributed to hemodynamic intolerance.

LVESVI (odds ratio [OR]: 1.012; 95% confidence interval [CI]: 1.000-1.024; P=.043) and QRS complex duration (OR: 1.017; 95% CI: 1.003-1.030; P=.015) were found to be independently associated with the primary end point in multivariate analysis. Conversely, beta-blockers offered a protective effect (OR: 0.169; CI: 0.048-0.593; P=.006).

“Patients with DCM [dilated cardiomyopathy] are classically younger, with fewer comorbidities, and a lower expected mortality for non-cardiac causes compared to other etiologies of systolic HF [heart failure], reinforcing the importance of solid strategies to reduce arrhythmic events,” Dr Losurdo and colleagues wrote.

They added that most of the early events occurred within the third month of the study and no interventions were taken with patients who had implantable cardioverter defibrillators. It is also noteworthy that LV ejection fraction was not predictive of sudden cardiac death/malignant ventricular arrhythmias in the first phase of disease.

“Early preventive measures including wearable cardioverter defibrillator for patients at risk should be explored in randomized clinical studies and selection criteria should incorporate additional markets of risk other than conventional evaluation of left ventricular function,” researchers concluded.

Reference

Losurdo P, Stolfo D, Merlo M, et al. Early arrhythmic events in idiopathic dilated cardiomyopathy. JACC Clin Electrophysiol. 2016. doi:10.1016/j.jacep.2016.05.002.