Vakur Akkaya

Effect of Valsalva maneuver on surface electrocardiographic P-wave dispersion in paroxysmal atrial fibrillation

The purpose of this study was to investigate the effect of the Valsalva maneuver on P-wave durations and dispersion. After the Valsalva maneuver, we found that maximum P-wave duration increased, minimum P-wave duration decreased, and P-wave dispersion increased in controls, whereas the opposite was true for unselected patients with paroxysmal AF. It was concluded that patients with paroxysmal AF performing the Valsalva maneuver normalized their P-wave dispersion, thereby correcting the inhomogeneous intra-atrial conduction.

Heart rate variability in diabetes patients.

Diabetes mellitus can cause cardiovascular autonomic neuropathy and is associated with increased cardiovascular deaths. We investigated cardiovascular autonomic neuropathy in diabetics and healthy controls by analysis of heart rate variability. Thirty-one diabetics and 30 age- and sex-matched controls were included. In the time domain we measured the mean R-R interval (NN), the standard deviation of the R-R interval index (SDNN), the standard deviation of the 5-min R - R interval mean (SDANN), the root mean square of successive R - R interval differences (RMSSD) and the percentage of beats with a consecutive R - R interval difference > 50 ms (pNN50). In the frequency domain we measured high-frequency power (HF), low-frequency power (LF) and the LF/HF ratio. Diabetes patients had lower values for time-domain and frequency-domain parameters than controls. Most heart rate variability parameters were lower in diabetes patients with chronic complications than in those without chronic complications.

Improvement of Uremic Autonomic Dysfunction after Renal Transplantation: A Heart Rate Variability Study

Autonomic dysfunction in hemodialysis patients is one of the components of uremic neuropathy. In this prospective study, we investigated the effect of renal transplantation on uremic autonomic dysfunction with long-term time-domain and frequency-domain heart rate variability. Fourteen hemodialysis patients (10 male, 4 female; mean age 33 ± 11 (range 16–50) years) were examined before and at the early after transplantation period (mean 4.6 ± 1.5 (range 3–7.5) months). The mean time spent on hemodialysis was 16.7 ± 15.6 (range 6–65) months. In time-domain analysis, significant increases in all parameters except pNN50 (SD, SDANN, SDNN, rMSSD) were observed after renal transplantation (p < 0.01). In frequency-domain analysis, low-frequency (LF) (0.04–0.15 Hz) and high-frequency (HF) (0.15–0.40 Hz) spectral power were found to be significantly increased after renal transplantation (4.54 ± 1.04 vs. 12.58 ± 8.69 for LF (p = 0.005), 2.80 ± 1.0 vs. 6.50 ± 3.55 for HF (p = 0.005)), but the LF/HF ratio was not different from a pretransplant period (1.71 ± 0.349 vs. 1.85 ± 0.49, p = 0.26). It was concluded that autonomic dysfunction in hemodialysis patients is reversible and renal transplantation reverses the sympathetic and parasympathetic autonomic dysfunction simultaneously and at a relatively early stage.

Effect of diurnal variability of heart rate on development of arrhythmia in patients with chronic obstructive pulmonary disease

We examined the possible effect of diurnal variability of heart rate on the development of arrhythmias in patients with chronic obstructive pulmonary disease (COPD). Forty-one COPD patients (M/F: 39/2, mean age: 59+/-8.5 years) and 32 (M/F: 27/5, mean age: 57+/-11 years) healthy controls were included. Twenty-four hour ECG recordings were analyzed for atrial fibrillation (AF) or ventricular premature beats (VPB), and circadian changes in heart rate variability (HRV) were assessed by dividing the 24-h period into day-time (08:00-24:00 h) and night-time (24:00-08:00 h) periods. Night-time total (TP), low frequency (LF) and high frequency (HF) powers were similarly lower from day-time parameters in AF(-) COPD patients (HF 3.91+/-1 vs. 4.43+/-1.04 ms(2), P=0.001) and controls (HF 3.95+/-0.72 vs. 4.82+/-0.66 ms(2), P<0.001). The LF/HF ratios were also significantly reduced in the same patient groups (AF(-) COPD 1.35+/-0.21 vs. 1.27+/-0.19, P=0.04, controls 1.43+/-0.14 vs. 1.24+/-0.09, P<0.001). Night-time TP and LF were increased, HF unchanged and LF/HF significantly increased (1.11+/-0.25 vs. 1.19+/-0.27, P<0.05) in AF(+) COPD patients. Frequency of VPB was correlated with corrected QT dispersion (QTc(d)) (r=0.52, P=0.001) and the day-time/night-time HF ratio (r=0.43, P=0.02). Patients with QTc(d)>or=60 ms did not have the expected increase in night-time HF and had a statistically insignificant increase in LF/HF ratio. In COPD patients with QTc(d)<60 ms, circadian changes in HRV parameters were parallel with the controls. We concluded that COPD patients with arrhythmia had circadian HRV disturbances such as unchanged night-time parasympathetic tone and disturbed sympatho-vagal balance in favor of the sympathetic system all day long, which may explain the increased frequency of arrhythmia.

Autonomic dysfunction in vitamin B12 deficiency: a heart rate variability study.

This study was arranged to examine whether vitamin B12 deficiency may cause autonomic dysfunction. Time-domain and long-term frequency-domain heart rate variability parameters from 12 patients with pernicious anemia were compared to 12 age and sex matched controls. In B12 deficient patient group time-domain parameters; SDNN (100.4 +/- 37.86 vs. 131.91 +/- 26.94, P = 0.05), SDANN (87.00 +/- 37.77 vs. 118.83 +/- 26.22, P = 0.05) SD (39.41 +/- 13.32 vs. 53.41 +/- 15.39, P = 0.0221), rMSSD (21.41 +/- 10.00 vs. 28.5 +/- 8.42, P = 0.046) were significantly lower when compared to controls. Difference in pNN50 between groups were not statistically significant. In B12 deficient patients frequency-domain parameters; total power (23.08 +/- 9.89 vs. 34.75 +/- 9.56, P = 0.0078), low frequency power (13.5 +/- 6.57 vs. 22.75 +/- 7.25, P = 0.0069) and high frequency power (7.58 +/- 4.25 vs. 11.58 +/- 3.80, P = 0.0175) were significantly lower when compared to controls. It was concluded that B12 deficiency may cause autonomic dysfunction.

The role of HLA molecules in susceptibility to chronic rheumatic heart disease

Only a small fraction of the streptococcal pharyngitis progress to rheumatic carditis, which implies that environmental, host and microbial factors interact to cause an aberrant immune response against the antigens of the microorganism that cross‐react with cardiac tissues. Although there are numerous studies and a general consensus on the relation between human leucocyte antigen (HLA) class II antigens and rheumatic heart disease (RHD), the details and the culprit antigens are still controversial. The study was undertaken to examine 100 patients with chronic RHD and 100 controls for HLA class I and class II antigens for differences in prevalence. All samples were typed at the HLA‐DRB1/3/4/5 and DQB1 loci by the sequence‐specific primer (PCR‐SSP) method at low resolution. For HLA class I antigens, HLA‐B13 frequency was marginally increased in patients with RHD compared to controls without reaching statistical significance. For class II antigens, RHD patients had higher frequencies for HLA‐DRB1*01 (RHD 24%, controls 10%), DRB1*04 (RHD 35%, controls 26%), DRB1*07 (RHD 18%, controls 11%) and HLA‐DQB1*02 (RHD 32%, controls 17%) without reaching statistical significance, and significantly lower frequencies for DRB1*13 (Pc < 0.003, OR: 5.69), DRB5* (Pc < 0.003, OR: 33) and DRB3* (Pc = 0.03, OR: 2.66) compared to controls. It was concluded that host, microbial and environmental factors collude to create acute rheumatic fever (RF) and chronic rheumatic valve disease. The HLA‐DRB1*13, DRB5* and DRB3* were protective against the development of rheumatic valve damage.

The effect of angiotensin converting enzyme gene polymorphism on chronic allograft dysfunction in living donor renal transplant recipients.

Background. Chronic allograft dysfunction (CAD), the major cause of the failure of kidney allografts, may be caused by immunological and non‐immunological haemodynamic factors. Renin–angiotensin system has been implicated in the development of intraglomerular hypertension and has a central role on progression in chronic renal disease. Polymorphism in 16th intron of the ACE gene has been reported to predict the circulating angiotensin II levels. The aim of this study was to investigate the effect of the both recipient and donor angiotensin converting enzyme (ACE) genotype on the development of CAD in renal allograft recipients.

No Association between Deletion-Type Angiotensin-Converting Enzyme Gene Polymorphism and Left-Ventricular Hypertrophy in Hemodialysis Patients

Left-ventricular hypertrophy (LVH), a bad prognostic sign, is a common finding in hemodialysis patients. The aim of the study was to analyze factors, including angiotensin-converting enzyme (ACE) genotype that may have an effect on the development of LVH in hemodialysis patients. Seventy-nine hemodialysis patients (42 males, 37 females, mean age 37.7 ± 13.1 years) and 82 age- and sex-matched normotensive healthy controls (40 males, 42 females, mean age 35.6 ± 5.7 years) were included. Left-ventricular mass index (LVMI) was higher in the hemodialysis group compared to controls (170.1 ± 69.3 versus 84.9 ± 15.7 g/m2, p < 0.001). Fourty-three hypertensive patients in the hemodialysis group had an increased LVMI compared to 36 normotensive hemodialysis patients (194.2 ± 75.5 versus 141.2 ± 48.0 g/m2, p < 0.001). On univariate analysis, LVMI was found to be correlated with blood pressure (r = 0.38, p < 0.001), time spent on dialysis (r = 0.22, p = 0.02) and hemoglobin levels (r = –0.21, p = 0.03). No correlation was found between LVMI and age (r = 0.09, p = 0.22), predialytic creatinine (r = 0.09, p = 0.21) and albumin (r = –0.10, p = 0.18). On multivariate analysis for the predictors of LVMI, blood pressure, time spent on dialysis and hemoglobin levels were also found to be significant. LVMI in DD, ID and II genotypes were 155.0 ± 71.2, 181.6 ± 60.6, and 163.6 ± 83.4 g/m2, respectively (p > 0.05). No association between LVMI and DD genotype was found. ACE genotype distribution was similar in hemodialysis patients and healthy controls. It was concluded that LVH in hemodialysis patients was mainly related to hypertension, anemia and time spent on dialysis and the DD genotype had no effect on LVMI in hemodialysis patients.

Left ventricular hydatid cyst: An unusual location of Echinococcus granulosus with multiple organ involvement

Cardiac Echinococcus is rare but usually associated with fatal complications. An unusual case of cardiac hydatid cyst with multiple organ involvement is presented in which transesophageal echocardiography provided additional information and confirmed transthoracic echocardiographic findings.

The effect of fluvastatin of hyperlipidemia in renal transplant recipients: a prospective, placebo-controlled study.

Posttransplant hyperlipidemia is a common complication which may affect long term cardiovascular mortality. In this prospective, placebo-controlled study, 19 renal transplant recipients (11 male 8 female, mean age 31.2 ± 8.4 years) with good allograft function (serum creatinine <2 mg/dl) more than 6 months after transplantation were included. All the patients had hyperlipidemia (serum cholesterol >230 mg/dl and/or LDL-cholesterol >130 mg/dl) despite dietary interventions. The patients were treated with a triple immunosuppressive regimen. After a 8-week period of placebo plus diet regimen, the patients were put on fluvastatin plus diet for another 8 weeks. The patients were followed for its effect on lipid parameters and side effects. After convertion to fluvastatin, serum cholesterol (263.0 ± 31.6 vs 223.2 ± 31.6 mg/dl, p = 0.001), LDL-cholesterol (174.4 ± 28.3 vs 136.4 ± 28.5 mg/dl, p = 0.002), Apolipoprotein (Apo) A1 (131.1 ± 16.9 vs 114.7 ± 18.4 mg/dl, p = 0.001) and Apo B (109.0 ± 29.8 vs 97.3 ± 31.5 mg/dl, p = 0.02) levels decreased significantly. Serum levels of triglycerides, VLDL-cholesterol and HDL-cholesterol levels did not vary under fluvastatin. Serum lipoprotein (a) levels were also unchanged during the whole study period (24.9 ± 19.4 vs 23.1 ± 19.8 mg/dl, p > 0.05). We concluded that fluvastatin effectively decreased atherogenic lipoproteins such as serum cholesterol, LDL-cholesterol, Apo B in posttransplant hyperlipidemia, however fluvastatin had no effect on another independent risk factor of atherogenesis, serum lipoprotein (a) levels.