Major pulmonary embolism, a correlation of clinical findings, haemodynamics, pulmonary angiography, and pathological physiology.

Twenty-three patients with major pulmonary embolism were examined clinically and investi- gated by cardiac catheterization with selective pulmonary angiography. Two-thirds of the patients had clinical evidence of acute right ventricular strain. The electrocardiogram was con- sidered 'typical' of acute right heart strain in 39 per cent and the chest x-ray showed changes considered or suggestive of pulmonary embolism in 83 per cent. Important atypical clinical fea- tures included the absence of dyspnoea in one patient, absence of elevation of the jugular venous pressure in 2 patients, and conspicuous pulsus paradoxus in one patient. Wheezing was never seen. The pulmonary angiogram revealed saddle embolism in I3 per cent, severe occlusion of the right or left pulmonary artery in 6I per cent, and obstruction confined to lobar and more distal arteries in 26 per cent. The severity of pulmonary vascular obstruction was best indicated, not by the severity of pulmonary hypertension which was moderate, but by the severity of depression of the stroke volume and cardiac output.