ackground : The right ventricular infarction is frequently associated with acute inferior
myocardial infarction. It is seldom diagnosed by the conventional 12 lead electrocardiogram
(EKG). However, right precordial EKG has been proved highly sensitive and specific in
diagnosing the right ventricular infarction The right ventriculr infarction is said to be
associated with proximal right coronary lesions. The present study was performed to evaluate
the value of the right precordial EKG in predicting the proximal RCA lesion in acute inferior
wall myocardial infarction.
Methods : In order to observe the relation of the EKG change and coronary angiographic
findings in the RV infarction, 40 patients (men 36, women 4, mean age 57±2.4 years) with
an acute inferior myocardial infarction were examined. The right precordial electrocardiogram
recorded with 10 hours after the onset of chest pain, and coronary angiogram were analysed.
Results :
1) The nean amplitudes of r-waves were 1.4±0.9mm in V3R and 1.2±0.8mm in V4R.
The mean amplitudes of s-waves were 6.6±3.6mm in V3R, 4.2±1.9mm in V4R, 2.7±1.4mm
in V5R, 1.7±1.6mm in V6R. The mean r/s ratio in right precordial leads was less than I.The
configuration of T-wave was inverted in 40.8% of the patients in V3R, 38.6% in V4R, 38.5%
in V5R and 35.9% in V6R.
2) Of the 40 studied subjects, 22 were one-vessel disease, 14 two-vessel disease, 3
three-vessel disease and one normal coronary artery.
3) Twenty-eight patients had ST segment elevation in V3R, V4R and/or V5R, in which 23
had right proximal coronary stenosis 5 had right middle or distal coronary stenosis. Among
twenty three patients who had proximal right coronary stenosis & ST segment elevation in
V3R, V4R and/or V5R, 19 had single proximal right coronary stenosis, 4 had left anterior
descending or left circumflex coronary stenosis coincidently. All five patients that had middle
or distal right coronary stenosis and ST segment elevation in V3R V4R and/or V5R had
associated left anterior descending or left circumflex stenosis.
4) In the diagnosis of proximal right coronary stenosis, the sensitivity of ST segment
elevation in V3R, V4R and/or V5R is 92%, the specificity is 83%, and the predictive accuracy
is 82%.
Conclusion : Above results suggested that right precordial lead electrocardiogram in acute
inferior myocardial infarction is a good predictor of the proximal right coronary arterial
stenosis
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