PREMATURE VENTRICULAR COMPLEX MORPHOLOGY - A MARKER FOR LEFT-VENTRICULAR STRUCTURE AND FUNCTION

The shape of a premature ventricular complex (PVC) might reflect the presence or absence of myocardial disease. To test this, 100 patients with a PVC on a 12-lead electrocardiogram at cardiac catheterization or nuclear angiography were classified according to PVC morphology. Group 1 (n = 50) had PVC QRS complexes with either smooth and uninterrupted contour or with narrow (< 40 msec) notching. Group 2 (n = 50) demonstrated PVC with broad (≥ 40 msec) notching or shelves. Clinical, electrocardiographic and angiographic variables were assessed to define group differences. All patients had one or more etiological forms of heart disease none of which distinguished either group. Groups 1 and 2 differed with respect to a history of congestive heart failure (12% vs 66%, p = 0.0004), dilated cardiomyopathy (2% vs 38%, p = 0.0005), and the presence of mitral regurgitation (13% vs 58%, p = 0.001), respectively. In group 1, 45 of 50 (90%) patients with a PVC had no notching. Patients in group 2 had greater PVC QRS duration as compared with patients in group 1 (181 ± 6 vs 134 ± 3 msec, p = 0.0001). End-diastolic volume index (EDVI) (78 ± 3 vs 139 ± 11 ml/m2, p = 0.0000) and ejection fraction (EF) (0.59 ± 0.02 vs 0.34 ± 0.03, p = 0.0000) significantly discriminated between group 1 and 2, respectively. By defining left ventricular structure and function as EDVI less than or equal to 90 ml/m2 or greater than 90 ml/m2 and EF equal to or greater than 0.50 or less than 0.50, sensitivity was 92% and specificity was 80% for PVC morphology. We conclude that a broadly notched PVC of long duration (≥ 160 msec) is a simple and reliable 12-lead electrocardiographic marker for a dilated and globally hypokinetic left ventricle in a nonspecifically diseased heart while a PVC with smooth contour or narrow notching whith short duration (< 160 msec) reflects a normal size heart with normal or near-normal systolic function despite the presence of underlying disease.