Prognostic implications of fragmented QRS and its relationship with delayed contrast-enhanced cardiovascular magnetic resonance imaging in patients with non-ischemic dilated cardiomyopathy

Abstract

BACKGROUND: We determined the relationship between fragmented QRS (fQRS) on electrocardiograms (ECG) as well as myocardial fibrosis measured by delayed enhancement of cardiac magnetic resonance imaging (DE-CMR) and its prognostic implication in patients with non-ischemic dilated cardiomyopathy (DCM). METHODS: The ECGs of 86 subjects with dilated non-ischemic DCM who underwent DE-CMR were analyzed. DCM was defined as LV end-diastolic dimension >55 mm with LVEF <45% and chronic symptomatic heart failure for ≥ 9 months. Cardiac events (re-hospitalization due to heart failure, arrhythmic event, cardiac death) were reviewed retrospectively. fQRS was defined by the presence of an additional R wave (R"), or notching of the S wave, or the presence of more than one R prime in two contiguous leads. RESULTS: In 86 patients, fQRS developed in 53 patients (61.6%) and delayed enhancement was observed in 42 patients (48.8%). The mean ejection fraction was 25.0%. Baseline characteristics were similar in both groups. Analyses of echocardiographic parameters revealed left ventricular end-diastolic and end-systolic dimensions were significantly higher in the fQRS group, but that the left ventricular ejection fraction was not significantly different. The prevalence of delayed enhancement between two groups was not significantly different (50.9% in fQRS vs. 45.5% in the non-fQRS group; p=0.62). MACE-free survival was significantly decreased in the fQRS group compared with the non-fQRS group. CONCLUSION: There was no spatial relationship between fQRS and DE-CMR in patients with non-ischemic DCM. fQRS was associated with lower event-free survival for major cardiac events on long-term follow-up.