Central haemodynamics during spontaneous angina pectoris

The haemodynamic significance of asymptomatic ST segment depression assessed by ambulatory pulmonary artery pressure monitoring

A transducer-tipped catheter with simultaneous frequency modulated electrocardiograms and a miniaturised tape recorder was used to record ambulatory pulmonary artery pressure for 24-48 hours in 19 men (mean age 57.7) with clinical and angiographic evidence of coronary artery disease. Sixty seven episodes of ST segment depression (greater than 1 mm) were recorded. Thirty five were accompanied by pain of which six occurred at night; in 34 pulmonary artery diastolic pressure rose significantly. In all but two of the 32 episodes of painless ST segment depression (four of which were at night) there was a significant rise in pulmonary artery diastolic pressure. No such rise was found in six normal subjects during exertion. ST segment changes tended to occur before (24 episodes) or at the same time (27 episodes) as changes in pulmonary artery diastolic pressure. ST segment depression followed an increase in pulmonary artery diastolic pressure in only 13 episodes. The times to maximum ST depression and maximum pulmonary artery diastolic pressure rise were similar. Painful and painless ST segment depression could not be distinguished on the basis of the configuration of the ST segment or in terms of the changes in the pulmonary artery diastolic pressure.

Mechanisms of nocturnal angina pectoris: importance of increased myocardial oxygen demand in patients with severe coronary artery disease

Changes in heart rate before and throughout episodes of ST-segment depression were recorded during ambulatory electrocardiographic monitoring in five patients with daytime and nocturnal resting angina and six patients with daytime angina only, who all had severe obstructive coronary disease. In 16 of 17 nocturnal episodes and in all the daytime episodes the heart rate increased before the onset of ST-segment depression. There were no significant differences in the sequence and magnitude of changes in daytime, nocturnal, painful, or painless episodes. The maximum heart rate during individual episodes preceded the maximum ST-segment depression by a mean 80.7 s and in the majority of episodes the heart rate returned to baseline before the ST segment. Thus, in severe coronary artery disease the mechanisms producing nocturnal resting ischaemia were apparently similar to those during daytime exertion; increased myocardial oxygen demand not coronary spasm seemed responsible for most of the episodes of nocturnal ischaemia.

Haemodynamic and electrocardiographic accompaniments of resting postprandial angina

The early postprandial changes in 10 patients with angiographically proven coronary artery disease and history of postprandial angina were studied by the continuous recording on magnetic tape of the electrocardiogram and haemodynamic variables. The significant changes 20 minutes after a meal not followed by angina included increases in cardiac index and stroke index, with a decrease in systemic vascular resistance. When angina developed after a meal, there were significant increases in mean systemic arterial blood pressure, heart rate, pulmonary capillary wedge pressure, and systemic vascular resistance with decreases in stroke index at the onset of pain rather than at the onset of ischaemic electrocardiographic abnormalities. The first haemodynamic variable to change was pulmonary capillery wedge pressure which tended to increase coincident in time with the electrocardiographic abnormalities. In all cases, postprandial angina occurred within 25 minutes after a meal. In every instance, there was little or no change in the product of heart rate and systolic arterial blood pressure at the onset of the ischaemic electrocardiographic abnormalities at a time when the pulmonary capillary wedge pressure had begun to rise. Postprandial angina, like many cases of rest angina, may rise on the basis of a primary decrease in myocardial perfusion, the nature of which is unclear but merits further investigation.

Patterns of haemodynamic alteration during left ventricular ischaemia in man. Relation to angiographic extent of coronary artery disease

Haemodynamic changes produced by rapid atrial pacing (60 patients, 52 of whom developed angina) or in association with spontaneous angina (32 patients) were measured in 92 patients with angiographic coronary artery disease. The extent of coronary artery disease was scored by the jeopardy score system (range 0 to 12). The haemodynamic changes induced by ischaemia occurred in 3 patterns: pattern I, no change in filling pressure or in mean systemic arterial pressure; pattern II, a rise in filling pressure and a rise in mean systemic arterial pressure; pattern III, a rise in filling pressure, but no significant change or a fall in mean systemic arterial pressure. In patients who had a pattern II or a pattern III response to ischaemia, the change in mean systemic arterial pressure was linearly related to the corresponding change in cardiac output. The likelihood of a patient showing a given pattern of ischaemia-induced haemodynamic change was related to the extent of coronary artery disease; of 22 patients with jeopardy scores of 2 or 4, 91% exhibited pattern I, 9% pattern II, and none pattern III; of 39 patients with jeopardy scores of 6 or 8, 40% exhibited pattern I, 22% pattern II, and 38% pattern III; of 31 patients with jeopardy scores of 10 or 12, 12% exhibited pattern I, 10% pattern II, and 78% pattern III (P less than 0.01). Among the 54 patients in whom serial cardiac output determinations were available, a decline of the left ventricular function curve during ischaemia was demonstrable in 8% of those with a pattern I response, in 54% of those with a pattern II response, and in 90% of those with a pattern III response (P less than 0.01). The pattern of response was unrelated to resting angiographic left ventricular ejection fraction, whether ST segments became elevated or depressed, or whether ischaemia was pacing-induced or spontaneous. These results suggest that the haemodynamic response to ischaemia is determined by the fraction of the left ventricle that becomes dysfunctional during ischaemia.