No abstract

Heart rate is a well-established indicator of emotional arousal and can serve to detect emotional events. One difficulty, however, is in separating emotional heart rate increases from those increases due to physical activity. On-line analysis of both heart rate and physical activity (recorded with motion detectors) with a portable minicomputer may be able to solve this problem. We have developed a special algorithm that compares the values for heart rate and activity of a particular minute with the values of the previous minutes. If heart rate of a specific minute exceeds the rate of the previous minutes without an accompanying increase of activity, an emotional event may possibly be assumed. In such a case, the patient is requested by a beep signal to answer relevant questions about what he is doing, how he feels, etc. Moreover the patient is allowed to activate the system for himself for special events, e.g. chest pain. Methodological results of a first feasibility study with 32 cardiac patients are presented.

Several hypotheses describe the phenomenon asymptomatic myocardial infarction (MI) blockade of afferent cardiac nerves, pain inhibition by endogenous opioids, and insufficient severity of myocardial ischaemia. Psychological factors, however, are rarely considered. The present study involved 35 asymptomatic (AMI) and 35 symptomatic patients (SMI) selected from a sample of 199 patients with myocardial infarction. During observation in a rehabilitation clinic, the following were assessed: biochemical variables; ECG at rest, at exercise, and during Holter monitoring; and a special 23 h monitoring of physical activity, ECG changes, and subjective feelings. Psychological assessments with questionnaires were also performed and comprised: personality evaluation; physical complaints; possible predisposing features for the development of MI; expectations regarding the benefit of rehabilitation; circumstances at the time of infarction; and socioeconomic and historical data. The hypothesis that physiological factors might explain the differences between AMI and SMI is not substantiated by our results. However, the hypothesis of the role of psychological factors is supported. As opposed to AMI patients, SMI patients are characterized by frequent complaints of poor health, neuroticism, and introversion. At the time of infarction, SMI patients had more frequent premonitory symptoms of longer duration. Moreover, SMI patients had more frequent previous hospital or nursing home admissions. At the end of the rehabilitation treatment, only 43% of the SMI patients were judged by their physician as fit for work as against 71% of the AMI patients.

Laboratory studies with CHD patients suggest an adverse influence of emotional/mental arousal on myocardial ischaemia or ventricular premature contractions (VPCs). However, it is controversial whether such studies can be generalized to everyday life. In addition, existing ambulatory monitoring studies have shortcomings because emotional arousal is entirely based on subjective reports. The hypothesis of the present study is that during ischaemic episodes or VPCs “objective emotional/mental arousal” will be more pronounced than during comparable episodes without these events. Objective emotional/mental arousal was indicated by a special ambulatory monitoring method which was based on the online analysis of heart rate and physical activity, resulting in the so-called emotional or non-metabolic heart rate. Moreover, the method allowed for ratings of anginal pain. In 223 CHD patients the associations between ischaemia, VPCs, objective emotional/mental arousal, and anginal pain were investigated. Forty-nine patients revealed ischaemic episodes and 115 patients VPCs. Emotional/mental arousal was higher during ischaemic episodes as compared to control minutes whereas minutes with VPCs showed no difference. No differences between ischaemic episodes or VPCs and the respective control minutes were observed for anginal pain. Objective emotional/mental arousal was associated in this study with ischaemia but not with arrhythmia, thus partly confirming the hypothesis stated. Because anginal pain was not related to objective cardiac events, detection of CHD has to rely on medical examinations.

ECG and physical activity (recorded with motion detectors) were continuously monitored during 23 hours in 31 male cardiac patients (81% with myocardial infarction). According to the occurrence of ventricular arrhythmias (VA) or ischemic episodes (IE), each patient was grouped in one of three diagnostic categories: neither VA nor IE, VA with or without IE, and IE only. Analysis of the ECG parameters was done beat-by-beat and averaged on a 1-min basis. Results were derived from the 2-hour means between 2 p.m. and 12 p.m. MANOVA revealed significant group differences for heart rate variability (greater for the group with VA), R-wave amplitude (higher for the group with IE), and P-wave amplitude (higher for the group with VA). Significant time effects were observed for all variables except QRS- and P-wave durations. As may be expected, physical activity and heart rate were lower at night. Heart rate variability, PQ-interval, PR-segment, QT-interval, ST-segment, and T-wave duration increased during the night. R-wave amplitude also increased but the relative P- and T-wave amplitudes decreased. The corrected QT-interval, QTc, was shorter at night and the ST-segment, J + 60-point, S-wave, and J-point amplitudes were less negative. Group X Time interactions were observed for T-wave amplitude. For this amplitude, the decrease during the night was prominent only for the VA group. The results of this study suggest that the three diagnostic groups can be differentiated by diverse ECG parameters.