SUMMARY This study was undertaken to assess both the relation between echocardiographic measurement of left ventricular (LV) mass and commonly used electrocardiographic criteria for LV hypertrophy and the effect of the distance from the center of LV mass to the anterior chest wall on precordial voltage. Echocardiograms and standard 12-lead electrocardiograms were obtained on 100 persons, ages 3 to 79. The and .531, respectively. Extrapolating from the dipole nature of the heart, the precordial voltage was multiplied by the square of the chest wall to mid-LV distance to correct for the loss of energy across the distance from LV to recording electrode. Utilizing this correction, a much improved precordial voltage estimation of LV mass (r = .846) was obtained. We conclude that the distance of the center of LV mass from the chest wall influences the amplitude of recorded precordial voltage and that correction for this influence improves the correlation of precordial voltage with LV mass. diomyopathy in two, and no discernible cardiovascular disease in 25 (some patients had more than one condition). Patients with known coronary artery disease, asymmetric septal hypertrophy, intraventricular conduction defects or pericardial effusions were excluded because of possible effects on ECG voltages or left ventricular echo measurements. The echocardiograms and electrocardiograms were independently evaluated by two of the authors and their measurements were averaged.The echocardiograms were obtained using a Smith Kline Instruments Ekoline 20A ultrasonoscope interfaced with an Electronics for Medicine VR6 strip chart recorder. The echocardiograms were obtained with the patients recumbent and in full expiration. A 1.25 cm diameter 2.25 MHz crystal transducer was used to obtain full M mode scans of the left ventricle and outflow tract. The transducer position was considered optimal for the measurement of LV volume and wall thickness when both leaflets of the mitral valve were recorded with the transducer perpendicular to the chest wall and with clear definition of both the septum and the left ventricular posterior wall endocardium immediately below the tips of the mitral valve leaflets.'8 Septal thickness, left ventricular posterior wall (LVPW) thickness, and left ventricular internal diameter (LVID) were measured at end diastole, as determined by the peak of the R wave on the ECG. The most anterior linear echo recorded was considered to represent the chest wall-transducer interface. The end-diastolic distances from the chest wall to the midseptum (DCW-Mid IVS) and mid-LV posterior wall (DcwMid LVPW) were measured at the same level of the echo sweep. The chest wall to mid-LV distance (DcW-Mid LV) was calculated by adding the mid-septal distance to the mid-LV posterior wall distance and dividing by two (Dcw-Mld LV = [Dcw-Mid Ivs + DcW-Mid LVPW] /2), ( fig. 1).Using the echocardiographically-determined dimensions, LV volumes were calculated for each patient assuming that the LVID was equal to the minor axis (D) of a prolate elli...
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