Early electrocardiographic diagnosis of left ventricular hypertrophy in hypertensive patients.
This study included 25 hypertensive patients with "normal" standard 12-lead scalar electrocardiogram and an equal number of age- and sex-matched controls. We recorded routine twelve leads, posterior chest leads, ensiform lead, right-sided precordial leads, lead CM5 and oesophageal electrocardiogram at different levels in all individuals. In addition we recorded an unconventional unipolar lead with the chest electrode placed on the thoracic seven spine. We also recorded some unconventional bipolar leads, in each instance using V5 as the positive electrode and the T7 spine, or the oesophageal electrode as negative. We observed that the T wave height of 20% or less of R wave amplitude in lead I was highly specific (92%) and sensitive (76%) in detecting early left ventricular hypertrophy in hypertensive patients, with the standard 12-lead electrocardiogram considered "normal" by conventional criteria. The T wave amplitude of 15% or less of the accompanying QRS in lead V6 was nearly equally diagnostic (specificity 88% and sensitivity 68%). An S wave of 0.3 mV or more in the bipolar lead recorded with the positive electrode at V5 and the negative electrode on T7 spine was also highly specific (80%) and sensitive (72%). Isoelectric or inverted T wave in lead V8, ST segment depression and T wave inversion in lead CM5 and ST segment depression in the bipolar lead recorded with the positive electrode at the V5 position and negative electrode at the atrial level of the oesophagus were highly specific (100%) but had a low sensitivity (40, 36, 16, and 28%, respectively). Combined lead V8 and lead I further improved the sensitivity to 96% without decreasing the specificity.
D000328:Adult; D006332:Cardiomegaly / Q000175:diagnosis* / Q000209:etiology; D004562:Electrocardiography; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications*; D008297:Male; D008875:Middle Aged; D013997:Time Factors