P wave analysis in ischaemic heart disease. An echocardiographic, haemodynamic, and angiographic assessment.

Fifty-two men with stable angina pectoris, without associated valvular heart disease or congestive failure, were studied to assess the electrocardiographic P wave abnomalities and their relation to left atrial size, pressure, and left ventricularfunction.Their mean age was 52years.Duration ofP waves in leads II, III, and aVF and the P terminalforce in Vl were examined.Echocardiograms were obtained to assess left atrial size and left atrial-aortic ratio.These measurements were also made in 33 normal subjects.Mean pulmonary artery wedge pressure at rest and exercise, left ventricular asynergy, ejectionfraction, and severity of coronary artery disease were determined in all 52 patients.P terminal force more negative than -002 mm s was noted in 69 per cent of coronary artery disease patients but in none of the normal subjects.P terminalforce correlated with exercise pulmonary artery mean wedge pressure but not with left atrial size.P wave duration in lead II did not correlate withpulmonary artery mean wedge pressure or left atrial size.P terminal force correlated with left ventricular contraction abnor- mality but not with ejection fraction or number of vessels diseased.It is suggested that chronic intermittent increases in left atrial pressure in association with angina pectoris result in left atrial hypertrophy which is responsible for the increased magnitude of P terminalforce in Vl in patients with ischaemic heart disease.