Cardiac function in chronic bronchitis: effects of pacing and plasma expansion

1. We have investigated left ventricular function in 25 selected patients with chronic bronchitis by use of atrial pacing and plasma volume expansion. Nine subjects had a past history of acute respiratory failure. None had either clinical or electrocardiographic signs of coronary heart disease. Paradoxical pulse was absent, since the difference between the highest and lowest systolic arterial pressure throughout the respiratory cycle was 5.4 +/- 1.5 mmHg. 2. During atrial pacing, at a mean rate of 145 +/- 15, about 80% of the predicted maximal rate, none of the patients showed anginal pain or ventricular repolarization abnormality. Cardiac output remained unchanged compared with control values. 3. Plasma volume expansion was achieved by intravenous injection of 1 litre of gelatin over 30 min. Cardiac output, pulmonary wedge pressure and right atrial pressure rose as reported in literature for normal subjects. In four patients cardiac output did not increase although wedge pressure and right atrial pressure did; two of these four patients also had an overshoot in pulmonary wedge pressure just after atrial pacing, suggesting left ventricular dysfunction. Three out of 25 patients had high control right atrial pressures, probably in relation to impaired right ventricular function. No paradoxical pulse occurred during plasma volume expansion. Therefore competition for space in the pericardium between ventricles was unlikely. 4. Our data suggest that left ventricular dysfunction is rare in patients with chronic obstructive pulmonary disease. There was no significant difference between subjects with and without a past history of acute respiratory failure.