Increased Left Ventricular Dimensions in Patients with Frequent Nonsustained Ventricular Arrhythmia and No Evidence of Underlying Heart Disease

INTRODUCTION: To test the hypothesis that frequent nonsustained ventricular premature beats (VPBs) in patients without underlying heart disease are the first marker of mild systolic dysfunction of the left ventricle, we evaluated whether a subclinical abnormality of left ventricular function and/or an intraventricular conduction defect was present at the first clinical documentation of the arrhythmia. METHODS AND RESULTS: We compared 57 patients (mean age 46 +/- 14 years) with > 30 VPBs/hour and no heart disease (A) to 32 healthy volunteers (mean age 42 +/- 12 years) without arrhythmia (B). Left ventricular echocardiographic parameters and signal-averaged ECG were evaluated. Filtered QRS duration (98 +/- 10 msec in A vs 98 +/- 7 msec in B) was similar in the two groups. End-diastolic left ventricular diameter (EDLVD) was 50 +/- 6 mm in A versus 47 +/- 3 mm in B (P < 0.005); 15 patients (26%) and none of the controls had EDLVD > or = 55 mm (P < 0.005). Filtered QRS interval was longer in the subgroup of patients (n = 15) with increased EDLVD (> or = 55 mm) compared with the subgroup (n = 42) with EDLVD < 55 mm (106 +/- 9 msec vs 95 +/- 9 msec; P < 0.001) and was related to greater left ventricular mass. CONCLUSION: We documented a subclinical but significant increase of left ventricular dimensions that suggests that frequent VPBs may be an initial marker of mild systolic dysfunction of the left ventricle. However, an effect of VPBs per se in modifying left ventricular dimensions cannot be excluded.