Diurnal variation in left ventricular function: a study of patients with myocardial ischaemia, syndrome X, and of normal controls.

Abstract

SUMMARY Angina can occur in the early morning. The mechanism of this is unclear and both haemodynamic changes and coronary artery spasm may be important. The purpose of this study was to investigate the diurnal variation in pulmonary artery diastolic pressure (an indirect measure of left ventricular filling pressure) in six normal subjects, 18 patients with coronary artery disease, five with variant angina, and six with syndrome X. A transducer tipped catheter and a simple recording system were used to record ambulatory pulmonary artery diastolic pressure for 24 hours. Variation in pulmonary artery diastolic pressure was related to the timing of episodes of ST segment depression and elevation by simultaneously recording a frequency modulated electrocardiogram. Episodes of ST segment change occurred predominantly in the early morning (midnight to 6 am) in variant angina (eight out of 14 episodes) whereas in syndrome X all episodes were recorded during the day. In coronary artery disease both painful and painless episodes were distributed throughout the day, with 10 out of 67 episodes occurring between midnight and 6 am. A similar diurnal variation in pulmonary artery diastolic pressure was seen in the groups-that is, values were low during the day and higher at night, with the maximum values between midnight and 6 am. The 24 hour median pulmonary artery diastolic pressure was higher in patients with coronary artery disease than in the control group and those with syndrome X.The finding that pulmonary artery diastolic pressure, and therefore left ventricular end diastolic pressure, is greatest in the early morning may represent the background haemodynamic state in which other factors lead to myocardial ischaemia during these hours.There is a well described diurnal variation in several physiological variables such as blood pressure, heart rate, cortisol, and catecholamines.'-4 This may have adverse consequences; for example myocardial infarction and cerebral infarction both show diumal variation.56 Angina may occur not only when the patient is active through the day but also in the early hours of the morning.79 Various pathophysiological mechanisms have been proposed, including an increase in myocardial oxygen consumption in patients with severe coronary artery Requests for reprints to Dr Richard D Levy,

Exercise-Induced Diastolic Abnormalities Assessed by Handgrip-Apexcardiographic Test in Syndrome X

“…To our knowledge, there are no corresponding studies based on either catheterization or non invasive acquired data during isometric exer cise in syndrome X patients. Although not directly comparable, our data are in accor dance with the findings of Bush et al [8] who reported a significant increase in LVEDP in all patients who had chest pain during catheter ization, but in contrast to the data of Levy et al [39] who failed to show an increase in pulmo nary pressure during spontaneous episodes of transient ST segment depression.…”

“…However, recent studies failed to show such ischemic signs [36], Alternatively, other authors sug gested the presence of cardiomyopathy in syn drome X [30,31,37,38], Many studies have shown the occurrence of left ventricular dysfunction at rest and dur ing exercise. It has been suggested that region al wall motion abnormalities during exercise or pacing are rather the result of demand isch emia [4,5,34,39]. Bush et al [8] found that 60% of syndrome X patients had an increased resting LVEDP, whereas all of them had a normal left ventricular ejection fraction.…”

Optimal Timing in Screening Patients with Congestive Heart Failure and Healthy Subjects During Circadian Observation

“…It could be attributable to diurnal changes in sympathetic activity. 25 Interestingly, our data show that the best timing paralleled with emergency department (ED) visits for all causes by hour of the day. 1 A previous report has identified a significant circadian variation in the patients with AMI onset of acute pulmonary edema (APE).…”

“…Various sliding widow widths were used to investigate the robustness of the observation time. They were 2, 5, 10,15,20,25,30,35,40,50,60,70,80,90,100,110, and 120 min, respectively. In order to find out the optimal timing during the temporal changes, all widows were shifted every 10 s from the beginning to the end of the data records.…”

Signal processing of intracardiac recordings for the evaluation of propofol effects during atrial fibrillation.

“…A circadian rhythm is seen in a range of physiological variables, including ar-terial [238] and pulmonary [239] blood pressure, body temperature, blood pH, hormone levels [240,241,242], and autonomic tone [243,244]. Furthermore, there are diurnal differences in levels of physical exertion, respiratory rate, and body posture.…”