Electrocardiographic left ventricular hypertrophy and the risk of adverse cardiovascular events: a critical appraisal

This review covers selected electrocardiographic left ventricular hypertrophy (ECG-LVH) studies which have evaluated their prognostic value for adverse cardiovascular (CVD) events. Most ECG-LVH studies have used echocardiographic left ventricular mass (Echo-LVM) as the gold standard for evaluating ECG-LVH criteria. More recently, LVM from magnetic resonance imaging (MRI-LVM) has evolved as the new gold standard. The reported risk of adverse CVD events is generally highest for ECG-LVH criteria which combine high amplitude QRS criteria with repolarization abnormalities such as in LV strain pattern. Evolving coronary heart disease (CHD) may account in part for the increased risk for ECG-LVH. However, one large coronary arteriography study found that 5-year survival was significantly lower in coronary artery disease (CAD) patients with ECG-LVH than without LVH regardless of CAD status. The utility of Echo-LVH as a standard is limited by the large intra- and inter-reader variability and the lack of standardization of allometric formulations for adjustment of LVM to body size. Newer evaluation data with MRI-LVM as the standard show that for most ECG criteria CVD event rates are significantly higher for study subgroups with ECG-LVH than those without ECG-LVH. However, the performance results differ when comparing the risk for CVD events from those for the overall LVH classification accuracy according to sensitivity and specificity. Large short-term variability of ECG amplitudes due to electrode placement variability is a common limiting factor for ECG-LVH criteria performance regardless of the gold standard. Clinical trials for hypertension control rely largely on monitoring Echo-LVH rather than ECG-LVH.