Niyazi Güler

Effects of cigarette smoking on the circadian rhythm of heart rate variability.

BACKGROUND The effects of cigarette smoking on the circadian rhythm of heart rate variability (HRV) are not known. METHODS We studied the effects of cigarette smoking on the circadian rhythm of HRV in 24 smoking and 21 non-smoking healthy subjects. Twenty-four hour ambulatory electrocardiograms were recorded and time domain parameters of HRV (SDNN [standard deviation of all R-R intervals], SDANN [standard deviation of the averages of R-R intervals in all 5-minute segments of the entire recording], RMSSD [the square root of the mean of the sum of the squares of differences between adjacent R-R intervals]) were determined for the entire 24-hour period and for each 3-hour period. RESULTS In total, SDNN and SDANN were significantly lower in smokers than non-smokers (116 +/- 26 vs 136 +/- 27, p < 0.05 for SDNN, 109 +/- 25 vs 121 +/- 24, p < 0.05 for SDANN). However, there were no statistical differences between smokers and non-smokers in heart rate (81 +/- 9 vs 76 +/- 10, p > 0.05) and RMSSD (32 +/- 12 vs 37 +/- 18, p > 0.05). These HRV parameters showed a circadian variation: they increased at night and decreased during the day in both groups. The parameters were lower in smokers than non-smokers during daytime (especially, between 8-14 hours). However, no differences were detected during night-time. CONCLUSIONS Time domain parameters of HRV (SDNN, SDANN and RMSSD) in both smoking and non-smoking healthy subjects have a circadian rhythm. SDNN and SDANN were lower in smokers than non-smokers during daytime.

Comparison of the effects of desflurane and sevoflurane on the QTc interval and QT dispersion

Objective — The effects of desflurane and sevoflurane on QT interval and QT dispersion have been investigated in a prospective, double-blind, randomized study of patients undergoing noncardiac surgery. Interventions — Sixty American Society of Anaesthesiologists physical status I-II adult patients were randomly assigned to two groups.Anaesthesia was induced with inhalation of desflurane (desflurane group) or sevoflurane (sevoflurane group) in increasing concentrations to 3 minimal alveolar concentration level. The maintenance of anaesthesia was provided with 2 minimal alveolar concentration agents in both groups until the end of the study. Electrocardiogram, heart rate and blood pressure were recorded as follows: before premedication, before induction, 1 and 3 min after the induction of anaesthesia, after the administration of vecuronium and after the tracheal intubation. The induction times and the complications were recorded. Measurements and results — The QTc interval was significantly more prolonged with desflurane than with sevoflurane at the first and third minute after the induction, and at the third minute after the administration of vecuronium.There were no significant differences in the QT dispersion between the two groups. Heart rate and blood pressure were found to be significantly higher in the desflurane group. Conclusion — The QTc interval was more prolonged with desflurane than sevoflurane, and QT dispersion was normal with both agents.

Frequency of Left Atrial Thrombus and Spontaneous Echocardiographic Contrast in Acute Myocardial Infarction

Left ventricular systolic dysfunction may precipitate blood stasis as well as thrombus formation in the left atrial appendage of patients with acute myocardial infarction, even in the presence of sinus rhythm. Thus, left atrial thrombi may be an alternative source for systemic embolism in acute myocardial infarction.

Heart rate recovery may predict the presence of coronary artery disease

OBJECTIVE We investigated whether post-exercise first minute abnormal heart rate recovery (HRR1) helps to predict the presence and severity of CAD, because of some confounding data. METHODS A cross-sectional, retrospective study was performed. Two hundred individuals were included. Gensini scores and the number of coronary artery involvements were used to evaluate the severity of CAD. Students t-test, Mann-Whitney U test and chi-square test were used for the analysis continuous and categorical data. Spearmans correlation analysis was used to determine whether there is correlation between Gensini scoring and HRR1. Univariate and multivariate logistic regression were used to determine predictors for abnormal HRR1. ROC curve analysis was performed to detect the best sensitivity and specificity value of HRR1 in predicting CAD presence. RESULTS Seventy subjects (35%) did not have CAD, and CAD was present in 130 patients (65%). HRR1 ≤21 beats with ROC analysis was determined to be the best cut off point. After adjustment between the two groups in terms of age, gender, diabetes, hypertension, dyslipidemia or smoking (all p>0.05), there was relationship CAD presence and abnormal HRR1 (OR=2.1, 95% CI: 1.1-3.9, p=0.02), but not between CAD severity and HRR1 (r=-0.13, p=0.112). The sensitivity, specificity, and the positive and negative predictive values of abnormal HRR1 ≤21 beats at first minute for predicting CAD presence were 76.1%, 41.3% (AUC=0.588, CI 95%: 0.517-0,657, p=0.039), 70.7% and 48.3%, respectively. CONCLUSION In the study abnormal HRR1 predicted the presence of CAD, but not the severity of it.

Aneurysm of Sinus of Valsalva Dissecting into Interventricular Septum: A Late Complication of Aortic Valve Replacement

A 43‐year‐old man who had a Carbomedics prosthetic aortic valve replacement in 1997 was admitted to our hospital with complaints of shortness of breath and dyspnea on exertion in 2000. The patient was hospitalized due to atrioventricular (AV) complete block and a permanent pacemaker was implanted. At that time echocardiography indicated an aneurysm at the left sinus of Valsalva. In 2003, the patient was re‐admitted to our clinic with complaints of shortness of breath and fatigue. Echocardiography showed a sinus of Valsalva aneurysm dissecting into interventricular septum. Operation confirmed dissection of the interventricular septum and communication between this cavity and the aneurysm of the left sinus of Valsalva. The postoperative course was uneventful and the patient was discharged in a satisfactory condition. This is the first reported case of aneurysm of the sinus of Valsalva dissecting into interventricular septum late and complicating aortic valve replacement.

Transesophageal echocardiographic detection of a pulmonary artery aneurysm complicated by thrombus

The incidence of aneurysms of the pulmonary artery is known to be very low. Although diagnosis and evaluation of pulmonary artery aneurysms may be difficult without angiography, computed tomography and MRIs have emerged as useful noninvasive techniques. However, a transthoracic echocardiogram may reveal a pulmonary artery aneurysm. To our knowledge, transesophageal echocardiographic findings of pulmonary artery aneurysm with thrombus have not been reported in detail. Here, a case of thrombosed aneurysm of the main pulmonary artery diagnosed by transesophageal echocardiography and confirmed by computed tomography and MRI is reported.

The effect of autonomic nervous system activity on exaggerated blood pressure response to exercise : evaluation by heart rate variability

OBJECTIVE We investigated the effect of autonomic nervous system activity on exaggerated systolic blood pressure (SBP) response to exercise in healthy subjects using heart rate variability (HRV) analysis. METHOD AND RESULTS We studied 53 healthy volunteer subjects with exercise treadmill test according to the Bruce protocol. Time domain and frequency domain of HRV were measured for each 5-minute segment before (rest) and after exercise (recovery) and during the total exercise period. The mean change in SBP (delta SBP) was 39 +/- 18 mm Hg. The delta SBP above the value of mean (> or = 40 mm Hg) was defined as an exaggerated delta SBP. According to the delta SBP, subjects were classified into two groups. Group I consisted of 32 patients who showed a normal delta SBP, group II consisted of 21 patients who showed exaggerated delta SBP. There were no significant differences in baseline clinical characteristics and exercise duration between the two groups. There were no significant differences in the mean RR intervals, SDNN (standard deviation of all RR intervals), RMSSD (the square root of the mean of the sum of the squares of differences between adjacent RR intervals), and HF (high-frequency power, 0.15 to 0.40 Hz) at rest between the two groups. However, LF (low-frequency power, 0.04 to 0.15 Hz) and LF/HF ratio at rest were significantly higher at rest in group II than in group I. There were no significant differences in the mean RR intervals and HF at exercise between the groups. However, SDNN and RMSSD were significantly lower, LF and the LF/HF ratio were significantly higher at exercise in group II than in group I. No differences in these parameters were observed at recovery between the two groups. CONCLUSIONS The sympathetic activity was higher at rest and during the total exercise period, parasympathetic activity was lower during the total exercise period in healthy subjects with exaggerated SBP response to exercise than in those with normal SBP response.

Does off‐pump coronary artery bypass surgery reduce secretion of plasminogen activator inhibitor‐1?

Prior studies showed that postoperative increase in plasminogen activator inhibitor‐1 (PAI‐1) levels is associated with an increased risk of graft occlusion after coronary artery bypass surgery (CABG). This prospective study aimed to compare the changes of PAI‐1 antigen levels after off‐pump and on‐pump CABG. Forty‐four patients admitted for elective CABG were randomised to on‐pump (n = 22) or off‐pump (n = 22) surgery. Serum samples were collected for estimation of PAI‐1 and tissue plasminogen activator (t‐PA) antigen levels preoperatively and 2 h after the operation. The groups were similar in terms of age, weight, gender ratio and extent of coronary disease, left ventricular function and number of grafts per patient. Fibrinogen and t‐PA levels increased postoperatively in both the groups when compared with baseline values. After operation, statistical analysis revealed that increase of PAI‐1 values was higher in off‐pump group (44.1 ± 9.1 vs. 25.3 ± 6.9) than on‐pump group (37.2 ± 5.5 vs. 27.3 ± 7.8, p = 0.002). This study shows that increase in PAI‐1 antigen values in patients who undergo off‐pump (beating heart) CABG is significantly higher than in those who undergo conventional CABG with cardiopulmonary bypass.

Effects of trimetazidine on submaximal exercise test in patients with acute myocardial infarction.

AbstractBackground: It was demonstrated that the novel metabolic agent, trimetazidine, could lessen the incidence and severity of angina, whether used in monotherapy or combination. Although the animal studies demonstrated that trimetazidine reduces myocardial infarct size and improves recovery of mechanic function after ischemia, little is known on the potential benefits of trimetazidine in patients with acute myocardial infarction (AMI). The aim of this study was to evaluate the efficacy of trimetazidine on AMI by sub-maximal exercise test. Methods: A double-blind crossover trimetazidine versus placebo trial was carried out in 44 patients with AMI. Patients were randomly allotted into trimetazidine (23 patients) or placebo (21 patients) for 5 days and underwent an initial sub-maximal exercise test. Exercise tests according to the modified Bruce protocol were performed. Exercise end points included completion of stage II or 75% of maximum predicted heart rate whichever came first. An averaged 12-lead ECG was obtained at rest, every minute during exercise, at the onset of anginal symptoms, at the onset of 1-mm ST segment depression, at peak exercise and every 2-minute during recovery. After the initial exercise tests, study groups resumed the drugs in the opposite order for 4 to 5 days and underwent a second sub-maximal exercise test. Results: Exercise induced ST segment depression was noted in 17 patients (38.6%) receiving placebo. However, exercise induced ST-segment depression was observed in 8 patients (18.1%) taking TMZ. Positive exercise test results were significantly higher in placebo group than TMZ group (p = 0.018). Additionally, trimetazidine prolonged the time to 1-mm ST-segment depression (6.1 ± 0.5 vs 4.9 ± 0.4, p < 0.031) and exercise duration (7.2 ± 0.9 vs 5.8 ± 0.9, p < 0.025). Conclusion: Trimetazidine therapy improves the exercise capacity and reduces evidence of ischemia derived from sub-maximal post-infarction exercise testing.

Heart rate variability in patients with iron deficiency anemia

FUNDAMENTO: A variabilidade da frequencia cardiaca (VFC) esta associada com aumento do fator de risco cardiaco em varias condicoes. As concentracoes de ferro apresentadas por um individuo podem ter um papel importante na saude cardiovascular. OBJETIVO: Avaliar a VFC em pacientes com anemia ferropriva. METODOS: Vinte e tres pacientes com anemia ferropriva (hemoglobina (Hb) media = 8,6±2,2 g/dl) e 10 individuos saudaveis ( Hb media = 13,9±1,2 g/dl) foram avaliados atraves de monitoramento ambulatorial por 24 horas (Sistema Holter) durante estadia hospitalar com atividade fisica limitada. RESULTADOS: Embora a frequencia cardiaca (FC) media tenha sido significantemente mais alta em pacientes com anemia, nao houve diferenca significativa em relacao aos parâmetros da VFC quando comparados ao grupo saudavel. CONCLUSAO: Nao ha diferenca significativa nos parâmetros da VFC entre pacientes com anemia ferropriva e individuos saudaveis.BACKGROUND Heart rate variability (HRV) is associated with increased cardiac risk factor in several conditions. The iron status of an individual may play an important role in cardiovascular health. OBJECTIVE To evaluate heart rate variability in patients with iron deficiency anemia. METHODS Twenty-three patients with iron deficiency anemia (mean hemoglobin (Hb) 8.6+/-2.2 g/dl) and 10 healthy people (mean Hb 13.9+/-1.2 g/dl) were assessed with 24-hour ambulatory Holter recordings during in hospital course having limited physical activity. RESULTS Although mean heart rate was significantly higher in patients with anemia, there was no significant difference regarding HRV parameters compared to the healthy group. CONCLUSION There was no significant difference in HRV parameters between patients with iron deficiency anemia with limited physical activity and healthy ambulatory people.