| Objective: Left ventricular hypertrophy ( LVH ) is an independent, primary risk factor and predictor for sudden death, coronary heart disease and congestive heart failure. Compared with autopsy and ultrasoundcardiography ( UCG ), the accuracy of LVH by electrocardiography ( ECG ) is generally believed to be low, especially it's sensitivity (20%—50%). We hypothesize that in patients with left ventricular hypertrophy and dilation, the depolarized plane and cardiovector will amplify towards the left-inferior due to the alteration of left ventricular position , so the QRS hoop will amplify primarily towards left-inferior in cardiovectorgram. The QRS hoop will leave the plane of V4,V5,V6. Therefore the common ECG's leads of V4,V5,V6 can't record the amplification of the maximal vector. So we put forward the lead of cardiac apex (Vapex) and consider it can record the amplification of cardiovector ( RVapex ), compare it with RＶ４,RＶ５,RＶ６and probe into the value of RVapex in identifying left ventricular hypertrophy.Methods: From 2001 .6 to 2001 .12, 111 patients were studied, including 69 male, 42 female.The participantswere free of thoracic deformity, cor pulmonale, emphy- sema, intraventricular block or pre-excitation syndrome, acute or remote myocardial infarction, pericardial effusion. All subjects underwent standard M-mode and two- dimensional UCG. Left ventricular dimensions ( ventricular septal thickness [VST], posterior wall thickness [PWT] and left ventricular internal dimension [LVID] ) were measured at end of diastole, left ventricular mass index (LVMI) was determined by using Devereux formula. According to chinese standard, LVH was defined as LVMI>125g/m2 (male) , 120g/m2 (female) and LVID>55mm (male), 50mm ( female ). All subjects underwent thoracic fluoroscopy to make clear the position of cardiac apex and record the QRS voltage ( RVapex ). Meanwhile all subjects underwent common ECG. The traditional electrocardiographic LVH was defined as a 12-lead total QRS amplitudes(∑QRS, a Romhilt-Estes point scores, Sokolow-Lyon voltage,NYHAC,RV6>RV5. Cornell voltage. All data was tested with SPSS software. Numercial variable date were expressed mean ± stand deviation ( X±S ), the paired and unpaired student t test were used. Relation between electrocardiographic voltage standard and LVMI was evaluated by linear analysis. Definitions of test sensitivity , specificity and accuracy conform to standard use. Cate- gorical variable date were assessed by chi-square test. A P value <0.05 was considered statistically significant . Results: 111 patients were divided into LVH group ( n=50, 30 male,20 female ) and control group ( n=61, 39 male,22 female ) by UCG .Two groups were simliar in age ,body surface area, but the mean LVM ,LVMI ,LVID of LVH group were respectively 298.89±76.71g, 176.37±48.26g/m2, 66.62±13.20mm, all they were significantly higher than control group ( P<0.001) . RVapex of LVH group was 27.40±9.99mm and significantly higher than control group ( RVapex was 17.34±6.02mm, P<0.001 ) . RＶ４,RＶ５,RＶ６ of LVH group were respectively 14.92±12.04mm, 20.76±12.15mm, 22.52±9.50mm ,all they were significantly lower than RVapex of the same group ( P<0.001 ). Meanwhile in control group ,RＶ４,RＶ５ were respectively 17.85±5.58mm, 17.65±6.85mm and were similar with RVapex ( P>0.50 ), but RＶ６was 13.71±4.70mm and was significantly lower than RVapex ( P<0.01 ). There were some correlation between most of electro- cardiographic voltage parameters and echocardiographic LVMI, but the correlation coefficients were generally low, the closest association was met between RVapex and LVMI ( r = 0.6455 , PNYHAC,RV6>RV5,Cornell voltage ( P...
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