Electrocardiographic diagnosis of left ventricular hypertrophy: the effect of left ventricular wall thickness, size, and mass on the specific criteria for left ventricular hypertrophy.

BACKGROUND: The purpose of our study was to determine the relative importance and effect of an increased left ventricle wall thickness, left ventricular diastolic diameter, and left ventricular mass (LVM) on the performance of the 4 major electrocardiogram (ECG) criteria of left ventricular hypertrophy (LVH) and to determine how these findings could be incorporated into the routine ECG interpretation of LVH.

METHODS: The ECG criteria of LVH that we chose to examine were voltage, repolarization abnormalities, left atrial abnormality, and ventricular conduction time. We analyzed data from 608 consecutive patients with left ventricular wall thickness of >13 mm on the echocardiogram and with a concurrent ECG. We arbitrarily divided patients into 3 groups (groups I-III) according to the calculated LVM. Group I had an LVM of <400 g; group II had an LVM from 400 to 600 g, and group III had an LVM of >600 g. We evaluated the effect of increasing LVM, wall thickness, and ventricular diameter on the performance of the 4 ECG criteria at different severity of thickness, diameter, and mass.

RESULTS: An increase in the echocardiogram-derived LVM had significant effect on all 4 ECG criteria. As LVM progressively increased from groups I to III, the frequency of voltage criteria for LVH increased from 52% to 83%; left atrial abnormality rose from 46% to 68%; ST-T wave changes increases from 55% to 95%, and QRS prolongation significantly increased from 42% to 70%.

CONCLUSION: Increased wall thickness and ventricular diameter failed to correlate with the overall ECG score or significantly influence the frequency of any of the 4 ECG criteria for LVH in patients when LVM was held relatively constant. We also demonstrated that an increasing number of criteria on the ECG are associated with a greater mean LVM.