Q waves in hypertrophic cardiomyopathy in relation to the distribution and severity of right and left ventricular hypertrophy

Abstract

The cause of abnormal Q waves in hypertrophic cardiomyopathy remains unclear. Myocardial wall thickness was assessed by two-dimensional echocardiography at 8 left ventricular and 10 right ventricular sites in 67 patients (mean age 40 years) with hypertrophic cardiomyopathy and the findings were analyzed in relation to the presence of abnormal Q waves on the 12 lead rest electrocardiogram (ECG). Nineteen (28%) of the 67 patents had abnormal Q waves. Right ventricular hypertrophy was significantly more common in patients without abnormal Q waves (25 [52%] of 48 versus 2 [11%] of 19, p < 0.001).With univariate analysis, there were six measurements that were significantly associated with abnormal Q waves: an increase in upper anterior septal thickness (p < 0.005) and maximal left ventricular wall thickness (p < 0.02), a decrease in mean and maximal right ventricular wall thickness (both p < 0.005) and an increase in the ratio of both upper anterior septal to mean right ventricular vall thickness (p < 0.005) and upper anterior septal to upper posterior wall thickness (p < 0.005). With multivariate analysis, only the ratios of upper anterior septal to mean right ventricular wall thickness (p < 0.005) and to upper posterior wall thickness (p < 0.05) were significantly related to the presence of abnormal Q waves and predicted Q wave location with a sensitivity, specificity and predictive accuracy of 90%, 88% and 89%, respectively.In hypertrophic cardiomyopathy, the presence of abnormal Q waves on the 12 lead ECG is primarily a function of the relation of right ventricular wall thickness and upper anterior septal thickness.