Şeref Demirel

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.

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.

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.

Percutaneous transluminal angioplasty for total coronary occlusion: The effect of restenosis on left ventricular function

The study was undertaken to evaluate the effect of restenosis on global and regional left ventricular function after percutaneous transluminal coronary angioplasty (PTCA) for total coronary occlusion. Thirty-one consecutive patients with total coronary occlusion treated successfully with PTCA and had follow-up angiography at 3–6 months formed the study group. Nineteen patients had restenosis (16 males, mean age 48±10 years) and 12 had no restenosis (11 males, mean age 53±10 years). In the LAD group there were increases in anterobasal (35.9±8.5% vs 43.1±5.7%, p=0.05) and apical (24.1±6.8% vs 31.7±2.9%, p=0.03) segment motion scores in patients without restenosis after PTCA. Global ejection fractions (63.1±14.5% vs 68.9±12.4%, p=0.09) and anterolateral (28.7±11.3% vs 39.7±10.2%, p=0.09) segment scores increased, but did not reach statistical significance. In the LAD restenosis group anterobasal (41.5±14.3% vs 34.3±12.6%, p=0.001), apical (21.1±15.0% vs 17.8±10.9%, p=0.05) and anterolateral (32.7±19.6% vs 26.6±13.8%, p=0.03) segment motion scores decreased but the decrease in the global ejection fraction (60.3±18.5% vs 58.6±17.4, p=0.38) was not significant. In the RCA+LCX group there was a significant increases in global ejection fraction (69.0±7.5% vs 74.2±7.6%, p=0.03) and posterobasal (23.8±7.8 vs 34.4±8.0, p=0.04) segment motion scores in patients without restenosis. The wall motion scores were unchanged in patients with restenosis in the RCA+LCX group. It was concluded that restenosis after a successful PTCA for total coronary occlusion may deteriorate segmental wall motion and treatment modalities with increased patency rates should be used for total coronary occlusions.