Abstract
Although there are four main characteristic electrocardiographic changes in ventricular hypertrophy which have been figured as high voltage of QRS complex, delayed ventricular activation time, ST and T change, changes in QRS pattern, any one of which as most reliable than others is yet inconclusive. The current study was undertaken to assess the significance of ventricular activation time (VAT) in the diagnosis of left ventricular hypertrophy. Methods : To provide the diagnostic criteria based upon VAT for left ventricular hypertrophy, examined 100 normal electrocardiograms, recorded with high speed (100 mm/sec.) and measured QRS interval and VAT in V5, 6. At present, however, no uniformity concerning the point for the onset of the intrinsicoid deflection is inconclusive. Therefore, we used three points which we considered to be reasonable as the onset of the intrinsicoid deflection. The point "a" is the peak of R wave, the "VAT-a" was measured from the onset of QRS to the point "a". "c" is the point which the downstroke of R wave cross over the zero line, then measured time was called "VAT-c". The point "b" is an onset point of steep intrinsicoid deflection ("VAT-b"). (Fig. 1) The positivities of ΣLVP and VAT criteria were compared in 105 cases of clinical hypertensive subjects and 18 cases with autopsy proved left ventricular hypertrophy. This will be acceptable, because these two criteria were determined at around normal upper limit (P98) in percentile distribution, assuming their false positivities will be the same (2%).
