Prediction of pharmacologically induced baroreflex sensitivity from local time and frequency domain indices of R-R interval and systolic blood pressure signals obtained during deep breathing.

Pharmacological measurement of baroreflex sensitivity (BRS) is widely accepted and used in clinical practice. Following the introduction of pharmacologically induced BRS (p-BRS), alternative assessment methods eliminating the use of drugs were in the center of interest of the cardiovascular research community. In this study we investigated whether p-BRS using phenylephrine injection can be predicted from non-pharmacological time and frequency domain indices computed from electrocardiogram (ECG) and blood pressure (BP) data acquired during deep breathing. In this scheme, ECG and BP data were recorded from 16 subjects in a two-phase experiment. In the first phase the subjects performed irregular deep breaths and in the second phase the subjects received phenylephrine injection. From the first phase of the experiment, a large pool of predictors describing the local characteristic of beat-to-beat interval tachogram (RR) and systolic blood pressure (SBP) were extracted in time and frequency domains. A subset of these indices was selected using twelve subjects with an exhaustive search fused with a leave one subject out cross validation procedure. The selected indices were used to predict the p-BRS on the remaining four test subjects. A multivariate regression was used in all prediction steps. The algorithm achieved best prediction accuracy with only two features extracted from the deep breathing data, one from the frequency and the other from the time domain. The normalized L2-norm error was computed as 22.9% and the correlation coefficient was 0.97 (p=0.03). These results suggest that the p-BRS can be estimated from non-pharmacological indices computed from ECG and invasive BP data related to deep breathing.

[Intrinsic cardiac ganglia]. / Kalbin içrek gangliyonlanmis nöral pleksusu.

Heart has been considered as the source and the seat of emotions, passion and love. But from the dawn of XIXth century, scientists have emphasized that the heart, though life depends on its ceaseless activity, is merely a electromechanical pump, pumping oxygenated blood. Nowadays, we all know that heart pumps blood commensurate with the needs of the body and this unending toil, and its regulation depends on the intrinsic properties of the myocardium, Frank-Starling Law and neurohumoral contribution. It has been understood, though not clearly enough, that these time-tensions may cause structural or functional cardiac impairments and arrhythmias are related to the autonomic nervous system. Less well known and less taken in account in daily cardiology practice is the fact that heart has an intrinsic cardiac nervous system, or "heart brain" consisting of complex ganglia, intrinsic cardiac ganglia containing afferent (receiving), local circuit (interneurons) and efferent (transmitting) sympathetic and parasympathetic neurons. This review enlightens structural and functional aspects of intrinsic cardiac ganglia as the very first step in the regulation of cardiac function. This issue is important for targets of pharmacological treatment and techniques of cardiac surgery interventions as repair of septal defects, valvular interventions and congenital corrections.

Echocardiographic findings in patients with Behçet's disease.

Case-controlled studies have shown that the prevalence of left ventricular (LV) diastolic dysfunction is higher in patients with Behçet's disease. However, there are no data evaluating the value of Doppler tissue imaging (DTI) in Behçet's disease. The aim of this study was to evaluate the cardiac involvement and the LV function at rest and at the end of isometric exercise by pulse-wave Doppler and DTI methods in patients with Behçet's disease. Fifty-four patients with Behcet's disease and 50 control subjects were studied. Dimensions of cardiac chambers, aortic root dimension, valvular abnormalities, and systolic function were similar in both groups. The mean E/A ratio was significantly lower in patients than controls (1.22 +/- .09 vs 1.36 +/- 0.30, p = 0.01). The E/A ratio was <1 in 12 patients (22%) and in 3 controls (6%) (p = 0.02). By DTI, no difference was found in the mean S-, e-, and a-wave velocities, and e/a ratio between the 2 groups. The e/a ratio was <1 in 13 patients (24.1%) and in 7 controls (14%) (p = 0.2) by DTI. There were no differences in the mitral pulse-wave Doppler and DTI parameters in patient and control groups at the end of exercise. The prevalence of cardiac pathology in Behçet's disease did not differ appreciably from the controls. In conclusion, the LV systolic and diastolic functions in the patients with Behçet's disease and controls were similar not only at rest but also at the end of exercise.

[Metabolic syndrome in patients after coronary bypass surgery: prevalence and compliance with treatment]. / Koroner baypas sonrasi hastalarda metabolik sendrom sikligi ve tedaviye uyum oranlari.

OBJECTIVE: The aim of this study was to evaluate the prevalence of metabolic syndrome (MS) and its components, to determine the patients' compliance with pharmacological therapy and lifestyle modification, and to clarify the association of demographic and socioeconomic factors with the MS in Turkish patients with prior coronary artery bypass surgery (CABG). METHODS: Two hundred and seventy-three patients (age range 35-77, 208 men) were interviewed and examined 1.0-2.2 years after CABG. RESULTS: The prevalence of MS was 44.8% (55.4% among women and 41.3% among men). The most prevalent metabolic risk factor was visceral obesity among females, and elevated blood pressure among males. Rates for regular physical activity were lower in patients with MS, compared with those without MS (36.9% vs. 47.7%, p<0.05). Compared with patients without MS, use of aspirin was lower among patients with MS (84.4% vs. 93.4%, p<0.05). Logistic regression analysis revealed an independent association of age>65 years and low educational level with MS. CONCLUSION: We found a high prevalence of metabolic syndrome and its components among patients with prior CABG. Patients with MS had lower rate of regular physical activity and aspirin use, compared with those without MS.

Prevalence of modifiable cardiovascular risk factors remain high after coronary bypass graft surgery: a multicentre study among Turkish patients.

BACKGROUND: The measures of secondary prevention in patients undergoing coronary bypass graft surgery (CABG) remains largely undetermined in Turkey. DESIGN: We designed a multicentre cross-sectional study to estimate the prevalence of cardiovascular risk factors in patients after CABG and to evaluate the association of demographic-socio-economic factors with secondary prevention in these patients. METHODS: A total of 622 patients who underwent CABG between 1 January 1999 and 15 January 2000 at four centres in Adana, Turkey; 273 (ages 35-77, 208 men) were interviewed and examined 1.0-2.2 years after the procedure. RESULTS: Of 273 patients interviewed, 81.5% were overweight, 65.5% had unhealthy food choices for a lipid-lowering diet, 56.0% were physically inactive, 28.8% were obese and 17.6% were current smokers. Hypercholesterolaemia, elevated blood pressure and fasting blood glucose were found in 65.6, 34.1 and 19.8%, respectively. Of diabetic patients, 63.8% had elevated fasting blood glucose. The use of angiotensin-converting enzyme inhibitors, beta-blockers and statins was low. Women had a higher rate of obesity and physical inactivity; smoking was less prevalent in females. More women were taking antihypertensive and lipid-lowering drugs than men. Logistic regression analysis revealed an association between hypercholesterolaemia and low educational level. CONCLUSION: Turkish patients have a high prevalence of modifiable risk factors related to unhealthy lifestyle and ineffective prophylactic drug use 1 year or more after CABG. Low educational level has a significant influence in this situation.

Effect of the final coronary arterial diameter after coronary angioplasty on heart rate variability responses.

BACKGROUND: Autonomic nervous system dysfunction and reduced heart rate variability (HRV) after percutaneous transluminal coronary angioplasty (PTCA) were reported in patients with coronary artery disease. However, factors related to reduced HRV are not clearly demonstrated. The aim of the present study was to assess the relationship between HRV indices and the final coronary arterial luminal diameter after PTCA. METHODS: Twenty-seven patients (23 male, 4 female, mean age: 52.5 +/- 7.1 years) with single vessel disease were included in the study. PTCA was performed in all patients. Low-frequency power (LFP), high-frequency power (HFP), and total power (TP) were calculated by using frequency-domain analysis of HRV. All examinations were performed 24 hours before, and 24 hours, 10 days, and 30 days after PTCA. The patients were divided into groups according to the PTCA restenosis risk score, the degree of dilatation, and revascularization after coronary angioplasty. RESULTS: The groups were comparable for age, gender, and coronary artery risk factors. HRV was found to be reduced in 76% of patients. Reduction in HRV after PTCA was significantly related to the PTCA risk score and the degree of revascularization (r = 0.48, P < 0.01 and r = 0.50, P < 0.008). Reduction in HRV was more significant in patients with previous myocardial infarction (P < 0.05). Recovery of HRV occurred on the tenth day after PTCA. CONCLUSION: Transient and rapidly recovered, especially parasympathetically modulated HRV reduction occurred after PTCA in patients with single-vessel disease. HRV reduction is associated with PTCA restenosis risk score and the degree of revascularization as invasive feature of angioplasty, hence it may be related to reperfusion.

Power spectral analysis of heart rate variability in children with aortic stenosis.

Aortic stenosis is a progressive disorder and can be the cause of serious arrhythmias and possibly sudden death. Evaluation and follow-up of the autonomic nervous system may provide some useful information for management of the disease. Our study aimed to examine heart rate variability in children with aortic stenosis in the supine position and to detect the changes in autonomic activity during head-up tilt testing. Sixteen patients and 11 healthy controls participated in the study. In the supine position, seven minutes of continuous echocardiographic (ECG) recording was performed, followed by four consecutive ECG recordings, each consisting of seven minutes in 70 degrees tilt position. To obtain power spectrums, the tachograms were taken on the autoregressive mode. The mean RR interval duration, standard deviation of RR interval, central frequencies of low and high frequency oscillations, their powers, total power and percents of normalized low and high frequency powers were accepted for statistics. There were no significant differences between the groups in the supine position. In tilt position, mean RR interval and its standard deviation were decreased in both groups. The central frequency of low freuquency power significantly (p<0.05) shifted to left, normalized low frequency power increased and normalized high frequency power decreased in the control group at the beginning of tilt position, but at the second phase of tilt position in the patient group. We conclude from the results that children with mild-to-moderate aortic stenosis reflect delayed response to sympathetic provocation.