Is the morphology of ventricular premature beats a marker for left ventricular dysfunction?

The morphology of ventricular premature beats has been described as a marker for the presence or absence of myocardial disease. Furthermore, the premature beat has been reported to be a potential marker for a dilated and hypokinetic left ventricle. To verify this previously tested hypothesis, 37 healthy patients with ventricular premature beats on an electrocardiogram (ECG), Holter monitor ECG, or a stress test ECG were classified according to the ventricular premature beat morphology. Group 1 had ventricular premature beat QRS complexes with a smooth contour or with narrow (less than 40 msec) notching. Group 2 had ventricular premature beats with broad (greater than 40 msec) notching or shelves. All of these patients had normal or borderline normal ECGs and normal multiple-gated acquisition (MUGA) scans. Nine patients had type 1 ventricular premature beats, 20 patients had type II ventricular premature beats, and eight patients had both type I and type II ventricular premature beats. We conclude that the presence of group 2 ventricular premature beats is so frequent in patients with normal left ventricular ejection fractions that the use of this marker in identifying abnormal left ventricular function is suspect.