The electrocardiogram in chronic bronchitis with generalized obstructive lung disease: Its relation to ventilatory function

Abstract

The electrocardiogram has been studied in an autospy series of 30 patients with chronic bronchitis and obstruction of airways (one form of generalized obstructive lung disease), and in a clinical series of 58 patients with this disease. In the clinical series an analysis was made of the relationship between the electrocardiogram and the one-second forced expiratory volume (F.E.V. 1.0). P pulmonale and electrocardiographic evidence of right ventricular hypertrophy are uncommon until the F.E.V. 1.0 is less than 45 per cent of predicted normal. It is at approximately this point that ventilatory capacity becomes inadequate to maintain normal blood gases. Positional changes in the P wave axis occur when ventilatory capacity is relatively well preserved and are believed to be positional in origin due to the increased residual volume of the lungs. Left ventricular hypertrophy unexplained by hypertension or myocardial ischemia was found in half of the autopsy cases. There was often no electrocardiographic evidence of its presence. Unexplained T wave changes are also common. Both these changes are thought to result from hypoxemia.