Ersel Onrat

Acute effect of cigarette smoking on heart rate variability

Acute cigarette smoking enhances adrenergic activity and thus may be associated with hemodynamic changes in the cardiovascular system. In this study, the acute effect of cigarette smoking on heart rate variability (HRV) was studied. Fifteen subjects were included in the study. Time domain (the mean R-R interval, the standard deviation of R-R interval, and the root mean square of successive R-R interval differences) and frequency domain (high-frequency, low-frequency ratio, and low-frequency/high-frequency ratio) parameters of HRV were obtained from all participants for each 5-minute segment: 5 minutes before and 5, 10, 15, 20, 25, and 30 minutes after smoking a cigarette. The mean R-R interval, the standard deviation of R-R interval, and the root mean square of successive R-R interval differences significantly decreased within the first 5-minute period compared with baseline, and then the standard deviation of R-R interval increased within the 20- to 30-minute period. The low-frequency high-frequency ratio significantly decreased within the first 5 minutes after smoking and then remained unchanged throughout the study period. Similarly, low-frequency and high-frequency power increased within the first 5 minutes compared with baseline. Acute cigarette smoking alters HRV parameters, particularly within the first 5 to 10 minutes after smoking.

Doppler echocardiographic evaluation of ventricular function in patients with rheumatoid arthritis.

Abstract Cardiac involvement in rheumatoid arthritis (RA) has been reported previously. However, evaluation of ventricular function in this disease by the use of recently proposed Doppler echocardiographic methods has not been reported before. Thus, the aim of this study was to evaluate ventricular function by measurement of myocardial performance index (MPI) and transmitral flow propagation velocity (TFPV). Thirty-two patients with long-standing RA and 32 control subjects (mean ages 52 ± 11 and 50 ± 10 years, respectively) participated in this study. Systolic function was assessed by subjective evaluation of wall motion for both ventricles and by fractional shortening for the left ventricle (LV). LV diastolic function was evaluated by standard pulsed-wave Doppler echocardiography, MPI and TFPV. Right ventricular (RV) function was evaluated by MPI. No subject had signs or symptoms of clinically overt heart failure. Systolic function was normal in all subjects. Among the echocardiographic indices of LV diastolic function the peak E velocity, E velocity/A velocity ratio, isovolumetric relaxation time, MPI and TFPV in the RA group were significantly different from those of the controls (P < 0.05). However, we did not observe a significant difference in RV echocardiographic indices between the two groups. Our results show that there is LV diastolic dysfunction in patients with long-standing RA. The lack of a history of cardiotoxic antirheumatic drug use among our patients suggests that this abnormality is due to RA itself.

The Comparative Cardiovascular, Pulmonary, Ocular Blood Flow, and Ocular Hypotensive Effects of Topical Travoprost, Bimatoprost, Brimonidine, and Betaxolol

OBJECTIVE This study evaluated systemic and ocular acute safety and intraocular pressure (IOP)-lowering efficacy of travoprost 0.004% and bimatoprost 0.03%, compared to brimonidine 0.2% and betaxolol 0.25% in healthy subjects. PATIENTS AND METHOD Nineteen (19) young men, ages between 24 and 42, were enrolled in a single-center, institutional randomized, double-masked, crossover clinical trial. Baseline IOP, heart rate, blood pressure, and respiratory rate were recorded at hour 0. At minute 30, heart rate, blood pressure, respiratory rate, and spirometry were measured. At hour 1, color Doppler imaging of retrobulbar vessels was performed. At hour 2, heart rate, blood pressure, and respiratory rate were measured; spirometry and a 15-minute treadmill test were performed. The same protocol was applied after one drop of a study medication was instilled into each eye on four subsequent visits at 5-day intervals. RESULTS Travoprost and bimatoprost did not cause significant reductions in systolic blood pressure during exercise and recovery. The mean respiratory rate and forced expiratory volume in 1 second were not significantly altered by any study medication. Travoprost reduced the resistive index and increased blood velocities in the ophthalmic artery and its branches. Bimatoprost caused a significant increase in end diastolic velocity of the ophthalmic artery. At hour 6, all medications reduced IOP significantly (p < 0.05). The most frequent ocular side effect of travoprost and bimatoprost was conjunctival hyperemia. CONCLUSION Travoprost and bimatoprost were found to be systemically safe and caused an increase in blood-flow velocities of the retrobulbar vessels after a single-dose application. Their ocular hypotensive effect was comparable to that of brimonidine and greater than that of betaxolol in healthy subjects.

Tissue Doppler Evaluation of Tricuspid Annulus for Estimation of Pulmonary Artery Pressure in Patients with COPD

Because transthoracic echocardiography is an inexpensive, easy, and reproducible method, it is the most commonly used noninvasive diagnostic tool to determine pulmonary artery pressure (PAP). Tissue Doppler imaging (TDI) emerged as a new echocardiographic method that can be applied in various clinical conditions. In our study we aimed to evaluate the relationship between tricuspid lateral annulus TDI parameters and pulmonary artery systolic pressure (PASP) as estimated by continuous wave Doppler in patients with chronic obstructive pulmonary disease (COPD). A total of 51 (42 men, mean age: 62.3 ± 8.2 years) patients with clinically stable COPD were included in the study. The tricuspid annular systolic myocardial velocity (Sm), velocity time integral of Sm (SmVTI), early (Em) and late (Am) peak diastolic myocardial velocities, and myocardial isovolumic relaxation time (IVRTm) were acquired as well as two-dimensional (2-D) and conventional Doppler data. When compared with values of patients without pulmonary hypertension (PHT), Sm, SmVTI, Em, and Em/Am values were found to be lower and IVRTm values higher in patients with PHT. When all the patients were analyzed, there was a significant negative correlation between PASP and Sm and SmVTI (r = −0.82, p < 0.001 and r = −0.84, p < 0.001, respectively). Sm velocity ≤ 12 cm/s had a sensitivity of 85% and a specificity of 93.3% for predicting PASP > 40 mmHg. SmVTI ≤ 2.5 cm had a sensitivity of 85.7% and a specificity of 90% for detecting PHT. In our study, there was significant negative correlation between tricuspid lateral annular Sm and SmVTI values and PASP in patients with stable COPD irrespective of the presence of PHT. Tricuspid annular Sm and SmVTI had very good level sensitivity and specificity for predicting PHT. In conclusion, it might be suggested that in cases where noninvasive PASP measurement is not possible, TDI can be used as an alternative and reliable method to assess PAP.

Single dose nasal 17beta-estradiol administration reduces sympathovagal balance to the heart in postmenopausal women.

Aim:  Long‐term estrogen replacement therapy has favorable results on autonomic cardiovascular functions in postmenopausal women. Although acute estrogen administration has beneficial modulations on autonomic tone in animal studies, there are still controversies about the effects of acute estrogen on autonomic modulation to the heart in humans. The aim of this double‐blind study was to investigate the acute effects of intranasal 17beta‐estradiol administration on autonomic control of heart rate.

Cardiac autonomic dysfunction in hemodialysis patients: The value of heart rate turbulence

Patients with end‐stage renal disease (ESRD) are likely to have cardiac autonomic dysfunction, which is related with an increased risk of sudden death. The aim of this study is to detect cardiac autonomic dysfunction in patients with ESRD and to evaluate the possible acute effects of hemodialysis (HD) on cardiac autonomic functions measured by heart rate variability (HRV) and heart rate turbulence (HRT). Thirty‐one (mean age 50 ± 13 years, 15 males) with ESRD on regular HD program and 31 healthy volunteers (mean age 51 ± 12 years, 15 males) were included in the study. Twenty‐four‐hour ambulatory electrocardiogram recordings were taken from the subjects before and after HD and from the control group. Heart rate variability and HRT parameters were calculated from these recordings. All of the HRV and HRT parameters were found to be significantly blunted in patients in comparison with healthy individuals. There were significant differences in HRV after HD, but similar differences were not observed in HRT parameters. Cardiac autonomic functions were significantly altered in patients with ESRD. Heart rate turbulence parameters seemed to be less affected from HD and may be more useful in the evaluation of cardiac autonomic functions in the ESRD population.

Effect of acute cigarette smoking on left and right ventricle filling parameters: a conventional and tissue Doppler echocardiographic study in healthy participants.

Acute effects of smoking on left and right ventricular function is determined by conventional and tissue Doppler imaging methods in this study. Pulsed-wave Doppler indices of the left and right ventricle diastolic function, including mitral and tricuspid inflow peak early and late velocity and their ratio were obtained from 20 healthy subjects by conventional Doppler and tissue Doppler imaging. Echocardiographic indices of left and right ventricles, including isovolumetric relaxation time, deceleration time, isovolumetric contraction time, ejection time, and myocardial performance index of right ventricle were measured before and 30 minutes after smoking a cigarette. Mitral and tricuspid inflow parameters and right ventricular myocardial performance index significantly altered after smoking a cigarette. Among the tissue Doppler imaging parameters, mitral and tricuspid lateral annulus diastolic, but not systolic, velocities altered after smoking a cigarette. Acute cigarette smoking alters left and right ventricular diastolic functions in healthy nonsmokers.

Sildenafil Citrate Does Not Affect QT Intervals and QT Dispersion: An Important Observation for Drug Safety

Background: Sildenafil is an effective and widely used therapeutic agent for erectile dysfunction. Deaths have been reported due to sildenafil use and most of them are attributed to concurrent use of nitrates. However, the effects of sildenafil on QT intervals, QT dispersion, and the possible risk of ventricular arrhythmia have not been studied before. Our aim in this study was to evaluate the effect of sildenafil citrate on QT intervals and QT dispersion.

The effect of dopamine type-2 receptor blockade on autonomic modulation

Abstract.Dopamine2 (D2)-like receptor antagonists are widely used for the treatment of gastroparesis and vomiting. Metoclopramide (MCP), a peripheral and central D2-like receptor antagonist, stimulates the sympathetic nervous system and may alter autonomic modulation, but the net effect of MCP to the heart is not known. The aim of our study was to investigate the effects of MCP on cardiac autonomic modulation, using power spectral analysis of heart rate variability.We evaluated the effect of MCP on cardiac autonomic modulation during prolonged supine and standing positions in 9 healthy men. We intravenously administered 10 mg MCP and placebo in a double blind and crossover manner to all participants during continuous electrocardiography recording. Placebo or MCP was administered after 15 minutes in supine position (REST phase), where participants remained for an additional 50 minutes (PSUP phase) and then stood up for 10 minutes (STA phase). Five-minute intervals were selected for power spectral analysis, and average values were calculated for low frequency (LF), normalized unit of LF (LFnu), high frequency (HF), normalized unit of HF (HFnu) components of the power spectrum, and for LF/HF ratio.Heart rate alterations were statistically significant during placebo administration (Friedman’s p < 0.0001). These changes were related to the decrease in PSUP phase and increase in STA phase in post hoc analyses. There was a trend toward lower LFnu in PSUP phase (Friedman’s p = 0.050), but LF/HF ratio changes did not reach a statistically significant level during placebo administration. MCP administration prevented the decrease in heart rate and LFnu component was seen with placebo in PSUP phase. Heart rate alterations also reached a significant level during MCP administration (Friedman’s p = 0.002), and post hoc analyses showed that these changes were mainly related to the increase in STA phase. In contrast to placebo, MCP administration resulted in significant alterations in LFnu and LF/HF ratio (Friedman’s p = 0.004 and p = 0.003, respectively). Two-way ANOVA model for LF/HF ratio changes showed that MCP induced a significant upward shift in LF/HF ratio than placebo during each phase of the study (F = 5.570; p = 0.031).We concluded that the net effect of MCP on sympathovagal balance is an increased sympathetic drive to the heart. MCP prevented the decrease in sympathetic drive to the heart during prolonged supine position and augmented sympathetic drive to the heart during mild sympathetic stimulation such as induced by standing up.

Cardiac autonomic function evaluated by the heart rate turbulence method was not changed in obese patients without co-morbidities.

Obese subjects are more prone to sudden deaths and arrhythmias than non-obese subjects. Heart rate turbulence (HRT) impairment reflects cardiac autonomic dysfunction, in particular impaired baroreflex sensitivity and reduced parasympathetic activity. Our aim was to evaluate the cardiac autonomic function in obesity by the HRT method. Ninety obese subjects and 112 healthy subjects were included in the study. Twenty-four hours ambulatory electrocardiograms were recorded and Holter recordings were analyzed. HRT parameters, turbulence onset (TO) and turbulence slope (TS), were calculated with HRT View Version 0.60-0.1 software program. HRT were calculated in 43 obese and 43 control subjects who had at least one ventricular premature beat in their Holter recordings. We excluded 47 obese patients and 69 control subjects who showed no ventricular premature beats in their Holter recordings from the statistical analysis. There were no significant differences in TO and TS between obese and control subjects (TO obese: -1.6±2.2%, TO control: -2.1±2.6%, p>0.05; TS obese: 8.2±5.2, TS control: 10.1±6.7, p>0.05, respectively). HRT parameters seem to be normal in obese patients without comorbidities.