Psychological aspects of cardiac arrhythmia

Association between stressful life events and resting heart rate

Background

Despite a diverse literature, the association between stress and various cardiovascular conditions remains controversial. Moreover, a direct association between stressful life events (SLEs) and heart rate (HR) have not been fully investigated. This study evaluated the association between SLEs and resting HR in middle-aged Koreans.

Methods

A cross-sectional analysis was conducted for 1,703 men and 2,730 women aged 27–87 years from the community-based Korean Genome and Epidemiology Study-Kanghwa study. All participants completed a baseline health examination. The life experience survey questionnaire was administered to measure SLEs experienced during the past 3 months. Resting blood pressure and HR were measured twice over a 5 minute interval. If the difference in blood pressure was more than 10 mmHg, then a third blood pressure and HR measurement was taken after 5 minutes of rest. The average of the last two measurements was used for analysis. The association between SLEs and HR was assessed by correlation and multiple linear regression analysis.

Results

Compared with people with no SLEs (mean HR of 67.30 beats/min), HR was significantly lower in those who experienced one (mean HR of 65.64 beats/min, p = 0.002), two (mean HR of 63.73 beats/min, p < 0.001), and 3+ SLEs (mean HR of 64.17 beats/min, p < 0.001). This association was observed even after adjustment for sex, age, body mass index, hypertension treatment, oral contraceptive use, postmenopausal hormone therapy, thyroid disease, liver disease, cigarette smoking use, alcohol drinking use, and blood urea nitrogen to creatinine ratio. Compared with people with no SLEs, those with 1, 2, and 3+ SLEs had a lower resting HR by 1.485 (p = 0.005), 3.718 (p < 0.001), and 3.176 (p < 0.001), respectively.

Conclusion

Our findings suggest that the experience of a recent SLEs are associated with a lower resting HR in Korean adults. Although further investigation is required, people who have experienced recent SLEs and have a lower HR than usual may need attention for their stress level.

Relation between ventricular arrhythmias and psychological profile

The association between psychological characteristics and ventricular arrhythmias was investigated in 150 men (50 with manifest IHD, 50 with risk indicators of IHD and 50 healthy men). Arrhythmias were recorded with 24-hour Holter monitoring. Psychological characteristics were assessed by the Emotions Profile Index and the Structured Interview for pattern A behaviour. A depressive emotional state was associated with prognostically severe ventricular arrhythmia in healthy men, but not in men with overt IHD or risk indicators of IHD. When clinical characteristics and age were taken into account, depressiveness was-among healthy men-the second most important factor after high age. The results suggest that-in absence of IHD or other cardiovascular disease-a depressive emotional state may participate in the formation of ventricular arrhythmia.

Cardiac arrhythmias and left ventricular hypertrophy in dipper and nondipper patients with essential hypertension

To evaluate the behavior of cardiac arrhythmias in dipper and nondipper hypertensive patients, 48-h ambulatory blood pressure monitoring, 24-h Holter electrocardiogram recording and echocardiographic studies were performed in 56 untreated outpatients with essential hypertension. These patients were divided into 2 groups according to the presence (dipper, n=33) or absence (nondipper, n=23) of reduction of both systolic and diastolic blood pressure during nighttime by an average of more than 10% of daytime blood pressure. Mean 48-h systolic and diastolic blood pressures did not differ between the 2 groups. Nondipper patients had a significantly larger left atrial dimension (31.9+/-3.8 vs 35.6+/-3.7 mm; p<0.01), left ventricular mass index (114+/-26 vs 136+/-36 g/m2; p<0.05), as well as a larger number of total supraventricular (16+/-19 vs 89+/-197 beats; p<0.05) and ventricular ectopic beats (7+/-14 vs 47+/-96 beats; p<0.05) during daytime as compared with dippers. In conclusion, nondipper hypertensive patients are likely to experience supraventricular and ventricular arrhythmias more frequently than dippers. A blunted nocturnal blood pressure fall may be involved in the appearance of cardiac arrhythmias in patients with essential hypertension.

Chaos theories and therapeutic commonalities among depression, Parkinson's disease, and cardiac arrhythmias

This report reviews and compares all therapies that have shown efficacy in depression and Parkinson's disease, although some are not in current use and others are at the experimental stage. They include pharmacological modification of neurotransmitter pathways, electroconvulsive therapy (ECT), sleep deprivation, psychosurgery, electrical stimulation through cerebral electrodes, and transcranial magnetic stimulation. Stemming from a pathophysiological model that stresses the brain as an open, complex, and nonlinear system, all therapies have been attributed a common mechanism of action. This report suggests that the therapeutic isomorphism is related to their ability to help the CNS deactivate cortical-subcortical circuits that are dysfunctionally coupled. These circuits are self-organized among neurons of their informational subsystem (rapid conduction) and modulating subsystem (slow conduction). Finally, this report extends the analysis and comparison of these therapies to some cardiac arrhythmias.

Idiopathic ventricular fibrillation

Idiopathic ventricular fibrillation is defined as cardiac arrest in the absence of structural heart disease and other identifiable causes of ventricular fibrillation. It occurs in 1% to 9% of survivors of out-of-hospital cardiac arrest. The mean age of these patients is 35 to 40 years, and 70% to 75% are male. The pathogenesis is unknown; psychosocial factors may play a role. Baseline clinical characteristics have not been found to identify the 20% to 30% of patients who will have recurrent cardiac arrest. At present, implantation of an automatic defibrillator is the treatment of choice. Two registries have been established to enhance our knowledge of this unusual catastrophic entity.

SR 33589, a new amiodarone-like antiarrhythmic agent: anti-adrenoceptor activity in anaesthetized and conscious dogs

We have assessed the ability of amiodarone and the new amiodarone-like antiarrhythmic agent, SR 33589 (N,N-dibutyl-3-[4-((2-butyl-5-methylsulphonamido)benzofuran-3-yl-c arbonyl) phenoxy]propylamine), to inhibit the effects of adrenoceptor stimulation in anaesthetized and conscious dogs. In anaesthetized, atropinized dogs, adrenoceptor stimulation was achieved (i) by i.v. administration of adrenaline and measurement of increased blood pressure (ii) by i.v. administration of isoprenaline and measurement of increased heart rate and decreased blood pressure. In conscious dogs, adrenoceptor stimulation was achieved by i.v. administration of isoprenaline and measurement of increased heart rate. In anaesthetized, atropinized dogs, both amiodarone and SR 33589 inhibited to similar extents, alpha-adrenoceptor stimulation (as indicated by attenuation of adrenaline-induced increases in blood pressure). The beta 1-adrenoceptor inhibitory activity of SR 33589 (as demonstrated by blockade of isoprenaline-induced increases in heart rate) was significant, but less marked than amiodarone (heart rate elevation reduced by 39%, P < 0.001 with 10 mg/kg SR 33589 and by 52%, P < 0.01 with 10 mg/kg amiodarone). In contrast, its beta 2-adrenoceptor antagonistic activity (as demonstrated by blockade of isoprenaline-induced reduction in blood pressure) was more marked (mean blood pressure decrease reduced by 69%, P < 0.01 with 10 mg/kg SR 33589 and by 31%, P < 0.05 with 10 mg/kg amiodarone). In conscious dogs, both SR 33589 and amiodarone (12.5, 25 and 50 mg/kg p.o.) inhibited isoprenaline-induced increases in heart rate by approximately the same amount for varying durations depending on the dose.(ABSTRACT TRUNCATED AT 250 WORDS)

The relation between event-related brain potential, heart rate, and blood pressure responses in an S1-S2 paradigm

Event-related brain potential (ERP), heart rate (HR), and blood pressure (BP) responses were examined during the 6 s foreperiod of a choice-reaction task. Low and high trait-anxious males were required to make same/different judgements based on the similarity of two successively presented visual patterns. The pitch of a warning tone, presented at the beginning of the foreperiod, indicated whether speed or accuracy was to be emphasized on that trial. In different conditions, subjects received either a monetary reward or aversive noise, depending on their performance. Two clusters of parallel variations were observed in the foreperiod: (1) speed/accuracy instructions affected the amplitude of the CNV and, in interaction with anxiety group, the initial decreases in HR and diastolic BP; (2) type of reward, in interaction with speed/accuracy instructions, affected the amplitude of the P300 and PSW, the mid-interval HR acceleration, and subsequent increases in diastolic and systolic BP. A correlational analysis showed a close relationship between changes in HR and BP, whereas no relationship was evident between changes in ERPs and changes in HR and BP.

Consideration of Physiologic Mechanisms in Animal Models of “Sudden Death”

Animal research of the “sudden death” phenomenon purporting to demonstrate causal psychological states has serious methodologic problems. Neither models nor the definition of the term, “sudden death,” are uniformly adopted; thus, the literature contains many conflicting reports. Further, much of the work has dealt with assumed psychological causation which is nontestable in nonverbal animals and tends to obscure study of quantifiable behavioral and physiological mechanisms.

A cry unheard: sudden reductions in blood pressure while talking about feelings of hopelessness and helplessness

This paper describes sudden extreme drops in blood pressure in both experimental and clinical situations when a person is talking about or describing situations of hopelessness and helplessness. These changes are discussed in the context of historical perspectives about the cardiovascular system. A new perspective is introduced, one in which these blood pressure changes are seen as part of an unheard cry for understanding. It is hypothesized that such changes do not occur in response to a person's attempts to communicate a sense of hopelessness, but rather are the biological foundations of the hopelessness itself. Viewed from such a context an entirely new therapeutic approach is outlined regarding the treatment of patients suffering from a wide variety of psychosomatic as well as psychological disturbances.

Determinants of ventricular ectopy in hypertensive cardiac hypertrophy

Left ventricular hypertrophy in arterial hypertension has repeatedly been documented to trigger or aggravate ventricular ectopy. To determine cardiovascular mechanisms underlying ventricular ectopy, we examined 53 hypertensive patients with mild to moderate nondilated left ventricular hypertrophy by 24-hour echocardiographic monitoring and two-dimensional (2-D)-guided M-mode echocardiography. Patients with more severe ectopy (Lown's class II to IV) were older and had greater increases in left ventricular mass, ejection fraction, velocity of circumferential fiber shortening, end-diastolic volume index, and left ventricular stroke work than patients with less severe ectopy (Lown's class 0 to I). Left ventricular mass, end-diastolic diameter, stroke volume, stroke work, ejection rate, velocity of circumferential fiber shortening, and fractional fiber shortening were enhanced in a subgroup with complex ventricular ectopy (multiform or paired premature ventricular beats or runs of ventricular tachycardia) when compared with a subgroup matched with respect to age, sex, body surface area, and mean arterial pressure, which had uniform monofocal ventricular beats occurring with a frequency of less than 10/hr only. Our data indicate that the frequency and severity of ventricular ectopy in patients with essential hypertension is determined by age, severity of left ventricular hypertrophy, chamber volume, and indices of contractility and pump function. Whether or not the pattern of ventricular ectopy will identify hypertensive patients with left ventricular hypertrophy who are at increased risk of sudden death remains to be determined.

Effects of propranolol, atenolol, and chlordesmethyldiazepam on response to mental stress in patients with recent myocardial infarction

Stress testing was carried out by two stressors, mental arithmetic and Sacks-Levy's test in randomized sequence, in 64 male patients with a mean age of 51 +/- 7 years in NYHA Classes I or II within 3 months after acute myocardial infarction. The stress profile was obtained after drug withdrawal by continuous recording of electrocardiogram, frontal electromyogram, and peripheral skin temperature and conductance. Blood pressure was measured each minute by cuff. The patients were subdivided into 4 groups of 16 each and were studied in an identical fashion after a 48-h oral treatment with propranolol 120 mg daily, atenolol 100 mg daily, chlordesmethyldiazepam 2 mg daily, or placebo. During stress, signs of myocardial ischemia or pump failure were not observed; minor arrhythmias were recorded. Cardiovascular activation was observed with significant increments (p less than 0.001) in heart rate, systolic and diastolic blood pressures in all 4 groups for both stressors with a slightly greater effect of mental arithmetic; Sacks' test was more effective on the frontal electromyograph response. Following beta blockade the stress profile of heart rate was significantly lower and flattened. The stress profile of blood pressure was also lower, but the reduction in the increment during stress was not significant. No differences were observed in the effects of the two beta blockers; no significant changes were evident in the stress profile of the noncardiovascular psychophysiologic indexes. Stress profiles were not altered by the benzodiazepine. In conclusion beta-blocker agents seem to be more useful than anxiolytic drugs in preventing cardiovascular activation induced by mental stress in patients with recent myocardial infarction.

Heart Rate Responses of a Head Referee During a Football Game

In brief: To determine the heart rate responses of a football official to both physical and psychological stress during actual game conditions, a head referee was telemetered continuously from one- half hour before until the end of a college football game. The referee's cardiac system was stressed throughout the monitoring period: The highest average heart rate was 161 beats min(-1) (85% of maximum), and the lowest average heart rate was 140 beats min(-1) (74% of maximum). Because officiating is largely anaerobic, the sustained sinus tachycardia was probably caused by psychological stress. Football officials should have a maximal ECG stress test every year and participate in an aerobic conditioning program on a regular basis.

Cardiac arrhythmia and conduction disturbances during sleep in 400 patients with sleep apnea syndrome

This report presents the first study of cardiac arrhythmias and conduction disturbance in a large group (400 patients) with sleep apnea syndrome studied between 1974 and 1979 with 24-hour Holter electrocardiography and a simultaneously recorded polygraph during late afternoon or nocturnal sleep. Of the 400, 193 patients (48%) had cardiac arrhythmias during the recorded night. The mean number of apneic events, age, weight and lowest oxygen saturation during sleep were not significantly different in those with arrhythmias. The most significant abnormalities were unsustained ventricular tachycardia in 8 patients, sinus arrest that lasted for 2.5 to 13 seconds in 43 patients, and second-degree atrioventricular conduction block in 31. Seventy-five had frequent (greater than 2 beats/min) premature ventricular contractions during sleep. Fifty patients with significant arrhythmias had a tracheostomy and were monitored again after surgery. No arrhythmia was present in these patients except for premature ventricular contractions.

The effect of status on blood pressure during verbal communication

Blood pressures and heart rates of 40 subjects were recorded at 1-min intervals over 35 min during which subjects engaged in a variety of verbal activities with either a high-status or an equal-status experimenter. All subjects showed statistically significant increases in blood pressure and heart rate when speaking compared to when quiet. Blood pressure increases during speaking of the 20 subjects exposed to a high-status experimenter were significantly greater than those of subjects exposed to an equal-status experimenter. While the blood pressure increase was related partly to the act of speaking, the amount of increase was also related to the social distance between experimenter and subject. The results are discussed relative to behavioral interventions for the treatment of hypertension.

Cardiac arrhythmias in the monkey during classically conditioned fear and excitement

Rhesus monkeys (Macaca mulatta) were tested in classic aversive and appetitive conditioning paradigms following complete coronary artery occlusion (CO) to test the hypothesis that "emotional stress" induces ventricular arrhythmias. Findings were based upon conditioning trials conducted for one or more weeks after occlusion in 13 animals. When all data from each animal for the week following CO were considered, there was no demonstrable tendency for arrhythmias to increase during "fear" conditioned to unavoidable electric shock or during "excitement" in anticipation of food. However, selected trials from six monkeys did reveal instances when changes in the frequency of occurrence of arrhythmias were coupled with behavioural conditioning. While analysis of these trials did not reveal any simple relationship between emotional stress and the development of ventricular arrhythmias after myocardial infarction, certain of the behavioral situations may be more potentially arrhythmogenic than others. For these selected trials, with respect to control, the number of arrhythmias may have increased or decreased upon presentation of the conditional stimulus; the exact response appears to depend upon the immediate physiologic status of the animal as well as on the behavioral condition. "More stressful" situations, such as aversive conditioning, are not necessarily associated with greater numbers of arrhythmias than were "less stressful" situations, such as appetitive conditioning. Arrhythmias appear to occur more frequently when an animal's heart rate is within a given range; this may reflect underlying cardiac sympathetic and parasympathetic nerve activity.

Beta-adrenergic influence on cardiac dynamics during shock-avoidance in dogs

The role of beta-adrenergic receptors in the mediation of the cardiodynamic effects of a shock-avoidance task was evaluated in conscious dogs with the cardioselective beta-adrenergic antagonist practolol. The animals were chronically instrumented for the measurement of peak rate of change of left ventricular pressure (LV dP/dt), heart rate (HR), cardiac output (CO), systolic (SPB) and diastolic (DBP) blood pressure and total peripheral resistance (TPR), and were each subjected to brief bouts of shock-avoidance with and without practolol pretreatment (2-4 mg/kg). Shock-avoidance evoked reliable increases of LV dP/dt, HR, CO, SBP and DBP, and decreases of TPR. Beta-adrenergic blockade virtually eliminated LV dP/dt increases, attenuated HR and CO increase as well as the vasodilatation, diminished SBP increases in certain animals but did not affect DBP increases. Stable interindividual differences in the magnitude of LV dP/dt and HR increases during shock-avoidance were demonstrated; these differences were abolished by beta blockade. These findings indicate that a beta-adrenergic mechanism accounted for most of the rise of LV dP/dt during avoidance but contributed proportionally less to the elevations of HR and CO. Inter-individual differences in myocardial reactivity were however completely ascribable to beta-adrenergic factors.

Psychosocial and behavioral influences in the pathogenesis of acquired cardiovascular disease

When taken together, studies relating psychosocial and behavioral factors to cardiovascular disease phenomena provide justification for the conclusion that such factors are importantly involved. We would emphasize the need to study and evaluate the interaction of environmental and biological factors in both laboratory studies of pathogenesis as well as in clinical studies of management. Indeed, upon careful scrutiny, even the accepted "nonbehavioral" risk factors such as hypercholesterolemia, hypertension, cigarette smoking, obesity, and sedentary lifestyles are each composite manifestations rather than single pathogens whose identities are powerfully impregnanted and bolstered by varieties of behavioral and psychosocial underpinnings. In view of the awesome impact of contemporary cardiovascular disease, both in terms of its increasing socioeconomic importance and its biologic devastation, we can not long afford comprehensive public health programs without increased and improved attention to psychosocial and behavioral influences in the pathogenesis of acquired cardiovascular disease.

Social environment as a factor in diet-induced atherosclerosis

Rabbits on a 2 percent cholesterol diet were individually petted, held, talked to, and played with on a regular basis. Measurements of aortic affinity for a Sudan stain, serum cholesterol levels, heart rate, and blood pressure were made at the end of the experimental period. Compared to control groups, which were given the same diet and normal laboratory animal care, the experimental groups showed more than a 60 percent reduction in the percentage of aortic surface area exhibiting sudanophilic lesions, even though serum cholesterol levels, heart rate, and blood pressure were comparable.

Heart Rates in Boat Racers

Six healthy, normotensive, experienced boat racers had high heart rates during races even though their work load was small, and the rates did not decrease with more experience.

Some aspects of sleep disturbance in coronary patients

Of 42 coronary care patients studied during 10 hr. of polygraphically recorded sleep, 28 were in an open-ward coronary care unit and 14 were in a semi-private telemetry unit. The observed sleep disturbances were not a function of type of unit, length of hospitalization, sex, or medications. Sleep was significantly less fragmented in those patients judged less severe in pathology. These results indicate that alterations in normal sleep patterns occur routinely within coronary care environments, even in the absence of disturbing environmental stimuli and suggest that a closer analysis be made of sleep in these settings in light of the known relationships between sleep and cardiac function.