Geometric determinants of electrocardiographic left ventricular hypertrophy
Experimental studies have suggested that electrocardiographic recognition of left ventricular hypertrophy depends on geometric relationships involving wall thickness and chamber size. To determine the clinical significance of these observations, we studied the effects of echocardiographic LV mass (LVM), posterior wall thickness (PWT), interventricular septal thickness (IVST) and internal dimension (LVID) on ECG voltage in 360 patients. Standard voltage and nonvoltage manifestations of LVH correlated modestly with LVM (r = 0.33-0.44, p less than 0.001). Sokolow-Lyon precordial voltage (SLV) (SV1 + RV5 or V6) correlated moderately with LVM (r = 0.41, p less than 0.001), but correlated less well with IVST (r = 0.26), PWT (r = 0.24) or LVID (r = 0.22). Stepwise regression revealed that there was no relation, independent of LVM, between SLV and IVST (r = 0.03), PWT (r = 0.03) or LVID (r = 0.01). The 90 patients with increased LVM (greater than 215 g) but without LVH by SLV (false negatives) were compared with the 48 identified by SLV (true positives). False negatives differed from true positives in LVM (298 +/- 72 vs 339 +/- 98 g, p less than 0.01), age (55 +/- 18 vs 44 +/- 19 years, p less than 0.001), weight (70 +/- 16 vs 63 +/- 14 kg, p less than 0.02), and distance from skin to the interventricular septum (42 +/- 10 vs 38 +/- 8 mm, p less than 0.02). Thus, for a given LVM, ECG voltage criteria of LVH are independent of LV chamber dilatation or other geometric variables, but depend on age, weight and LV depth in the chest, suggesting that stratification of subjects by clinical variables has promise for improved electrocardiographic recognition of LVH.