Nenad Lakusic

Characteristics of Heart Rate Variability in War Veterans with Post-Traumatic Stress Disorder after Myocardial Infarction

OBJECTIVE The goal of the study was to evaluate differences in heart rate variability (HRV) among post-myocardial infarction (MI) patients, depending on their participation in the Croatian war and on established diagnoses of post-traumatic stress disorder (PTSD). METHODS The study included 34 male war veterans with diagnosed PTSD who had suffered a first MI and 34 age-matched post-MI patients without PTSD. Cardiac autonomic balance was evaluated through HRV analysis. RESULTS There were no differences in the mean R-R interval or overall HRV between the analyzed groups. Post-MI patients with PTSD had lower values for the square root of the mean of squared successive differences in R-R intervals (p = 0.02), the percentage of R-R intervals that were > or =50 milliseconds different from the previous interval (p = 0.03), and the high-frequency component (p = 0.03) but had higher values for the low-frequency component (p = 0.01) and the low-frequency/high-frequency ratio (p = 0.02), compared with post-MI patients without PTSD. CONCLUSION Post-MI patients with PTSD have higher sympathetic and lower parasympathetic heart rate modulation activity, compared with patients with MI and no PTSD.

Different Cut-Off Points of Decreased Heart Rate Variability for Different Groups of Cardiac Patients

Background Heart rate variability (HRV) differs by the type and stage of the disease, by age, by environment, and so on. Criteria for normal, moderately changed and pathologic values of HRV lack for routine clinical work with different groups of cardiac patients. Methods Twelve time and frequency domain HRV variables were analysed from 24-h Holter ECG monitoring in 2578 consecutive patients of both sexes (57% male) aged 15-91 (mean 54 ± 13) years. Fifty-nine per cent of the patients were hospital out-patients, 15% came from the cardiac unit of an internal medicine department and 26% were undergoing stationary cardiac rehabilitation. Arrhythmias of aetiology other than coronary artery disease predominate in out-patients and coronary artery disease in in-patients. Limits of moderately and pathologically changed values were determined according to biostatistical principles. Results HRV differed by the age, sex and type of patients (MANOVA P < 0.001). Heart rate and all HRV measures decreased with age. Females had a higher heart rate but more pronounced vagally modulated activity than males. Out-patients had better HRV than in-patients. The cut-off level for a pathologic standard deviation of the normal R-R interval (a measure of overall HRV) ranged from 75 ms in female out-patients to 44 ms in male patients from the cardiac unit. Different cut-points for 12 HRV measures were obtained for 12 sub-groups of patients. Conclusion In view of the HRV differences between different cardiac patients, different limits of normal and decreased HRV are proposed for daily practice.

Heart Rate Variability after Off-Pump versus On-Pump Coronary Artery Bypass Graft Surgery.

Background. It is known that after coronary artery bypass graft surgery (CABG) heart rate variability (HRV) becomes significantly decreased with a gradual recovery in a few months after surgery. However, literature data about the impact of the off-pump CABG on postoperative HRV are not complete. Therefore, the aim of this study was to analyze postoperative value of HRV in CABG patients operated on with off-pump versus on-pump coronary surgery. Methods. This study included 206 consecutive patients who underwent CABG. Sixty six patients (32%) were operated on off-pump while 140 patients (68%) were operated on using the machine for extracorporal circulation. HRV was analyzed from 24-hours Holter electrocardiogram recordings. Results. No significant differences in postoperative values of HRV variables were found between off-pump versus on-pump CABG patients (Mean RR interval 885 ± 106 versus 879 ± 125 ms, standard deviation of all normal R-R intervals 107 ± 30 versus 105 ± 34 ms, NS, total power 2298 ± 2472 versus 2156 ± 1913 ms2, NS). Conclusions. The results of the study showed that there are no differences in HRV few months after surgery between patients operated on with off-pump versus on-pump CABG.

Heart rate variability in patients after cardiac valve surgery

The aim of study was to analyze heart rate variability (HRV) after different cardiac valve surgery procedures and the prognostic values of these findings. This study included 101 consecutive patients who underwent surgical implantation for an artificial valve. The mean age of the patients was 62 ± 10 years. An aortic valve was implanted in 65 patients. A mitral valve was implanted in 36 patients. HRV was analyzed from 24 hours Holter electrocardiographic (ECG) records. The time from the operation to the recording of Holter ECG and measuring HRV was 3.8 ± 1.4 months. After discharged from stationary cardiac rehabilitation, all involved patients were contacted to provide data on their health in the follow-up period (33 ± 21 months). A total of 46 patients with an implanted artificial valve had decreased overall HRV or standard deviation of all normal R-R intervals (SDNN) < 93 ms. Patients with an implanted artificial mitral valve had a shorter RR interval (817 ± 122 vs. 863 ± 122ms, p=0.03) and lower values of total power (1166 ± 1888 vs. 2802 ± 3601 ms2, p<0.001) compared to patients with an implanted artificial aortic valve. The results of study show that several months after cardiac surgery, almost half of the patients with an implanted artificial valve have decreased HRV. However, postoperative decreased HRV in those patients have no importance in long-term prediction of mortality rate.

Changes in Heart Rate Variability after Coronary Artery Bypass Grafting and Clinical Importance of These Findings

Heart rate variability is a physiological feature indicating the influence of the autonomic nervous system on the heart rate. Association of the reduced heart rate variability due to myocardial infarction and the increased postinfarction mortality was first described more than thirty years ago. Many studies have unequivocally demonstrated that coronary artery bypass grafting surgery generally leads to significant reduction in heart rate variability, which is even more pronounced than after myocardial infarction. Pathophysiologically, however, the mechanisms of heart rate variability reduction associated with acute myocardial infarction and coronary artery bypass grafting are different. Generally, heart rate variability gradually recovers to the preoperative values within six months of the procedure. Unlike the reduced heart rate variability in patients having sustained myocardial infarction, a finding of reduced heart rate variability after coronary artery bypass surgery is not considered relevant in predicting mortality. Current knowledge about changes in heart rate variability in coronary patients and clinical relevance of such a finding in patients undergoing coronary artery bypass grafting are presented.

Transient electrocardiographic recording of acute myocardial ischemia with ST-segment elevation of the diaphragmal location accompanied by a total atrioventricular block as an initial manifestation of Prinzmetal’s angina — A case report

Prinzmetal’s angina, also known as Prinzmetal’s variant or Prinzmetal’s vasospastic angina is characterized by angina attacks caused by spasm of the great epicardial coronary arteries. Coronary artery endothelial dysfunction plays a crucial role in the development of this vasospastic angina. The attacks of vasospastic angina can be prevented with calcium antagonists and nitrates, whereas in refractory variant angina, coronary angioplasty with stenting may help prevent further coronary spasm. In this case report, we present a 52-year-old male patient with a transient electrocardiographic recording of acute myocardial ischemia with ST-segment elevation of the diaphragmal location accompanied by a total atrioventricular block immediately after exercise testing and as a first manifestation of Prinzmetal’s angina. After regression of the symptoms and electrocardiographic changes, significant pathomorphologic changes of coronary arteries were excluded by coronary angiography. Following discharge, the patient was treated with calcium antagonists and did not show symptoms during a 4-year follow-up period.