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Biomedical subjects

Kudret Aytemir

Publications and source records attributed to Kudret Aytemir.

At least 19 recordsLinked to original sources
PubMed2006

Increased myocardial vulnerability and autonomic nervous system imbalance in obstructive sleep apnea syndrome.

BACKGROUND: Obstructive sleep apnea syndrome (OSAS) is characterized by the repeated episodes of upper airway obstruction during sleep, leading to significant hypoxia. Noninvasive evaluation of autonomic nervous system (ANS) and myocardial vulnerability may help determination of OSAS patients who are under high risk of malignant cardiac arrhythmias. The aim of this study was to show the effects of OSAS on predictors of arrhythmias by the evaluation of heart rate turbulence (HRT), heart rate variability (HRV) and QT dynamicity reflecting the ANS balance and myocardial vulnerability. METHODS: After polysomnographic study, 80 patients with OSAS and 55 age matched OSAS (-) subjects were included in the study. Twenty-four-hour Holter monitoring was performed in all subjects. HRT, HRV and QT dynamicity parameters were calculated. RESULTS: Turbulence slope was significantly decreased in OSAS patients whereas turbulence onset was increased (P<0.001). QT/RR slopes were significantly increased for QT end and QT apex (P<0.001). In HRV analysis, autonomic balance changed in favor of sympathetic system at night in OSAS patients. Furthermore, HRT and QT dynamicity parameters are found to be correlated with Apnea-Hypopnea Index (AHI). CONCLUSION: OSAS is associated with a significant worsening in HRV, HRT, and QT dynamicity parameters. Our results may indicate that HRV and QT dynamicity parameters can be useful noninvasive methods that may detect autonomic nervous system activity and ventricular vulnerability in OSAS.

Aged↗
PubMed2006

Does 16-MDCT angiography scanning direction affect image quality of coronary artery bypass grafts and the native coronary arteries?

To assess the impact of scanning direction on the image quality of coronary artery bypass grafts (CABGs), native coronary arteries (NCAs) were examined by electrocardiographically (ECG) gated 16-row multidetector computed tomography (16-MDCT). Eighty-two patients with 209 grafts were studied by 16-MDCT. Forty-one patients with 111 grafts were scanned craniocaudally. Forty-one patients with 98 grafts were scanned caudocranially. CABG, native coronary arteries were examined in four (proximal, middle, distal, distal anastomoses), three (proximal, middle, distal) segments, respectively. Subjective image quality on a four-point scale was calculated for segments. Scores of groups were compared. Results Image quality scores of proximal, distal segments of the right coronary artery (RCA) were better in caudocranially scanned group (P<0.05). When we subgrouped patients according to initial heart rates (IHR) (group 1, <65 beats/min; group 2, > or =65 beats/min), there was no statistical significance between image quality scores of coronary arteries, CABG when IHR was <65 beats/min in groups regardless of scanning direction. Scores of anastomotic segment of CABG to RCA, middle segments of circumflex coronary artery, proximal and distal segments of RCA in caudocranially scanned group were better when the IHR is > or =65 beats/min compared with the craniocaudally scanned group. When the IHR of the patient is > or =65 beats/min, performing ECG-gated 16-MDCT angiography in the caudocranial direction provides better image quality for evaluation of coronary arteries and CABGs.

Adult↗
PubMed2006

Coronary artery bypass grafting is associated with a significant worsening of QT dynamicity and heart rate variability.

BACKGROUND: Imbalance in autonomic nervous system and impaired myocardial repolarization has been shown to increase the risk for arrhythmias in patients with coronary artery disease. This study evaluated the effects of coronary artery bypass grafting (CABG) on heart rate variability and QT interval dynamicity in subjects with coronary artery disease undergoing elective CABG surgery. METHODS: The study group consisted of 68 consecutive patients (mean age +/-SD: 61 +/- 9 years) with coronary artery disease who underwent elective CABG. Twenty-four-hour Holter monitoring was performed 2-5 days before cardiac surgery and was repeated 10 days after CABG. ELATEC holter software was used to calculate heart rate variability and QT dynamicity parameters. All subjects had a complete history, laboratory examination and transthoracic echocardiography. RESULTS: All patients had beta-blocking agent medication pre- and postoperatively. Standard deviation of all NN intervals for a selected time period, square root of the mean of the sum of the squares of differences between adjacent RR intervals, the proportion of differences in successive NN intervals greater than 50 ms, normalized low-frequency power, and normalized high-frequency power were significantly decreased after CABG surgery, whereas low-frequency/high-frequency ratio was significantly increased after CABG. QT/RR slopes over 24 h were significantly increased after CABG surgery for QT end and QT apex (QTapex/RR: 0.16 +/- 0.13 vs. 0.28 +/- 0.19, p < 0.001; QTend/RR: 0.18 +/- 0.13 vs. 0.36 +/- 0.23, p < 0.001). CONCLUSION: This prospective study showed for the first time that CABG was associated with a significant worsening of heart rate variability and QT dynamicity parameters in the postoperative period.

Adrenergic beta-Antagonists↗
PubMed2006

A permanent junctional reciprocating tachycardia with an atypically located accessory pathway successfully ablated from within the middle cardiac vein.

Permanent form of junctional reciprocating tachycardia (PJRT) is an uncommon form of atrioventricular re-entrant tachycardia due to an accessory pathway characterized by slow and decremental retrograde conduction. The majority of accessory pathways in PJRT are localized in the posteroseptal zone. Despite the high success rate, failure may occur during endocardial radiofrequency catheter ablation due to epicardial insertion of the accessory pathway. We report a case of PJRT in a 25-year-old man in whom the accessory pathway was located epicardially in the posteroinferior region and ablated from within the middle cardiac vein by radiofrequency catheter ablation.

Adult↗
PubMed2006

The effect of VVI pacing on P-wave dispersion in patients with dual-chamber pacemakers.

The incidence of atrial fibrillation is higher in patients with VVI pacing mode than DDD pacing mode, but the likely mechanism is not clearly understood. We aimed to evaluate whether short-term VVI pacing increases inhomogeneous atrial conduction by using P-wave dispersion. Forty-seven patients (32 men, 15 women, mean age 54 +/- 13 years) with DDD pacemakers were enrolled in this study. Twelve-lead surface ECGs were obtained in all patients during VDD pacing after an observation period of 1 week. The mode was then changed to VVI and 12 lead surface ECGs were obtained after another 1-week observation period. P-wave durations were calculated in all 12 leads in both VDD and VVI pacing modes. The difference between the maximum and the minimum P-wave duration was defined as the P-wave dispersion (PWD = P(max) - P(min)). P-wave maximum duration (P(max)) calculated in VVI pacing mode was significantly longer than in VDD pacing mode (128 +/- 19 vs 113 +/- 16 ms, P < 0.001). There was no significant difference in the P-wave minimum durations (80 +/- 13 ms vs 79 +/- 12 ms, P = 0.7) between VVI pacing and VDD pacing. The P-wave dispersion value was higher in the VVI pacing mode than in the VDD pacing mode (48 +/- 8 ms vs 34 +/- 7 ms, P < 0.001). Short-term VVI pacing induces prolongation of P(max) and results in increased P-wave dispersion, which might be responsible for the development of atrial fibrillation more frequently in these patients than in those with the VDD pacing mode.

Adult↗
PubMed2006

Value of 99mTc-methoxyisobutylisonitrile (99mTc-MIBI) gated SPECT for the detection of silent myocardial ischemia in hemodialysis patients: clinical variables associated with abnormal test results.

BACKGROUND: Although coronary artery disease is a major cause of mortality and morbidity in patients undergoing hemodialysis, there is no accurate diagnostic strategy for these patients. AIM: To assess the value of 99mTc-methoxyisobutylisonitrile (99mTc-MIBI) gated single-photon emission computed tomography for the detection of silent myocardial ischemia in patients undergoing hemodialysis and to evaluate the clinical variables associated with abnormal test results. METHODS: Thirty-one asymptomatic patients undergoing hemodialysis (20 men, 11 women), with a mean age of 45 years (range, 25-75 years), were included in the study. Serum electrolytes, creatinine, homocysteine and adhesion molecules were measured prior to dialysis. Ambulatory blood pressure, carotid intima-media thickness measurements, echocardiography and stress 99mTc-MIBI imaging were performed in all patients, whereas coronary angiography was performed only in patients with abnormal myocardial perfusion scintigraphy and/or echocardiography. RESULTS: Gated myocardial perfusion scintigraphy results were abnormal in nine patients (29%) and coronary angiography was abnormal in six patients. After a median follow-up of 20 months (range, 14-28 months), nine patients experienced a cardiac event. Seven of the nine patients (78%) with abnormal myocardial perfusion scintigraphy suffered a cardiac event, compared with only two of 22 patients (9%) with normal myocardial perfusion scintigraphy (P<0.0001). Patients with abnormal perfusion scintigraphy had higher serum C-reactive protein, homocysteine and adhesion molecule levels and the duration of hemodialysis was significantly longer. CONCLUSION: In asymptomatic hemodialysis patients, gated myocardial perfusion scintigraphy is a safe and non-invasive screening technique for the detection of coronary artery disease and for predicting future cardiac events. The presence of ischemia correlates significantly with markers of inflammation. The discordant results (abnormal myocardial perfusion scintigraphy/normal coronary angiography) can be attributed to angiographically unrecognized occult atherosclerotic changes and abnormal vasodilatation capacity of the coronary circulation.

Adult↗
PubMed2006

Left and right ventricular function is impaired in Behçet's disease.

OBJECTIVES: Subclinical cardiac involvement may occur in patients with Behçet's disease (BD). The purpose of our study was to assess the noninvasive parameters of biventricular function derived from Doppler tissue imaging (DTI) of the tricuspid and mitral annular motion in BD. METHODS: Twenty-one patients with BD and 20 control subjects were enrolled in this study. All subjects were selected to exclude those with cardiovascular risk factors. Standard echocardiography and pulsed DTI were obtained in every patient. RESULTS: Peak systolic (13.71 +/- 2.09 vs 20.01 +/- 1.57, P < 0.001), peak early diastolic (11.26 +/- 2.52 vs 15.35 +/- 2.06, P < 0.001) tricuspid annular velocities were significantly lower in patients than controls. Peak systolic (8.68 +/- 1.4 vs 12.25 +/- 1.7, P < 0.001), peak early diastolic (7.89 +/- 1.07 vs 9.94 +/- 1.12, P < 0.001), and peak end diastolic (8.30 +/- 1.32 vs 9.23 +/- 0.91, P = 0.013) lateral mitral annular velocities were significantly lower in patients than controls. CONCLUSIONS: We demonstrated that myocardial velocities, were affected in patients with BD. Therefore, we conclude that right and left ventricular function is impaired in patients with BD.

Adult↗
PubMed2006

QT dispersion increases with aging.

BACKGROUND: Age-related changes in cardiovascular system are well-known. Arrhythmias in elderly patients constitute most of the urgencies, consultations, or hospitalizations. QT dispersion (QTd) is a simple noninvasive arrhythmogenic marker to demonstrate the electrical instability of the heart. The aim of this study was to investigate how QTd changes with increasing age by calculating the QTd in the elderly and younger subjects. METHODS: One hundred and forty-six consecutive subjects (62 males and 84 females; age range: 18-82 years) were enrolled in the study. Sixty-seven of the subjects were 65 years and over (mean age, 70 +/- 4), 79 were younger than 65 (mean age, 37 +/- 11). A 12-lead ECG was recorded. The longest and the shortest QT intervals were measured manually on these ECG recordings. QTd was calculated from the formula, QTd = QTmax - QTmin. RESULTS: Demographic features were similar between the two groups. QTd of the elderly group was found to be significantly higher than the younger group (35.6 +/- 15.6 in elderly, 24.2 +/- 12.4 in younger group, P < 0.001). A positive relationship was found between QTd and age (r = 0.415, P < 0.001). QTd was greater in female than in male (31.9 +/- 16.7 ms vs 26.0 +/- 11.3 ms, respectively, P = 0.018). CONCLUSIONS: Our study shows that QTd increases with advancing age. We think that long-term follow-up of these patients would be useful to show if there is any relationship between the clinical outcomes and the increase in QTd.

Adolescent↗
PubMed2006

P wave dispersion predicts recurrence of paroxysmal atrial fibrillation in patients with atrioventricular nodal reentrant tachycardia treated with radiofrequency catheter ablation.

BACKGROUND: Paroxysmal atrial fibrillation (AF) recurs in up to one-third of patients with atrioventricular nodal reentrant tachycardia (AVNRT) treated with slow pathway ablation. Therefore, identification of patients at risk for recurrence of AF after slow pathway ablation is important because of the necessity for additional therapies. The purpose of this study was to determine whether successful slow pathway ablation influences P wave parameters and whether these parameters predict the recurrence of paroxysmal AF in patients with both AVNRT and paroxysmal AF after ablation. METHODS: Thirty-six patients with AVNRT and documented paroxysmal AF (Group 1) were compared to 36 age-matched controls with AVNRT only (Group 2). P wave durations and P dispersion were measured before and after ablation. RESULTS: No significant differences were observed between P wave parameters observed before and after ablation. Maximum P wave durations (Pmax) and P dispersion (Pdisp) were significantly higher in Group 1 than in Group 2 (P < 0.001 for both) whereas minimum P wave durations did not differ between groups, both before and after ablation. Ten patients (28%) in Group-1 had recurrence of AF during a mean follow-up of 34 +/- 11 months. Univariate predictors of AF recurrence were Pdisp > or =35.5 ms (P < 0.010), left atrial diameter >40 mm (P < 0.010), mitral or aortic calcification (P < 0.010), Pmax > or =112 ms (P < 0.050), valvular heart disease (P < 0.050), and atrial vulnerability (induction of AF lasting >30 second) after ablation (P < 0.050). However, only Pdisp > or =35.5 ms (P < 0.050) and left atrial diameter >40 mm (P < 0.010) were independent predictors of AF recurrences. CONCLUSION: This study suggests that P wave dispersion could identify patients with AVNRT susceptible to recurrence of AF after slow pathway ablation.

Adult↗
PubMed2006

Heart-type, fatty-acid binding protein can be a diagnostic marker in acute coronary syndromes.

OBJECTIVES: Chest pain is one of the most common complaints among patients admitted to emergency departments. Cardiac troponins, CK-MB and myoglobin, which are used routinely in the diagnosis of acute coronary syndrome (ACS), are not elevated in the initial hours of ACS--precluding their usefulness in the early diagnosis. The aim of this study is to determine the efficacy of H-FABP compared to myoglobin and CK-MB in the early diagnosis of ACS. METHODS: Sixty-seven patients with ACS were enrolled in the study. An initial blood sample was obtained for CK-MB, cTnT, myoglobin and H-FABP. At the fourth, eighth, and 12th hours, repeat ECGs and cardiac enzyme samples were obtained. H-FABP test was repeated at the fourth hour. RESULTS: H-FABP has sensitivity equal to that of CK-MB and superior to that of myoglobin (97.6%, 96.7%, 85.4%, respectively) on the first hour. This trend extends to the fourth hour of myocardial injury as well. H-FABP was more specific than CK-MB, myoglobin and troponin T at the first hour (38.5%, 34.6%, 34.6%, 23.1%, respectively), whereas its specificity at the fourth hour was equal to those of CK-MB and troponin T and exceeded that of myoglobin. CONCLUSIONS: It can be suggested that in patients with an initial diagnosis of ACS and within 20 hours from symptom onset, H-FABP levels may be measured. For this purpose, point-of-care H-FABP test may be utilized, which has the advantage of bedside testing and rapid test results.

Acute Disease↗
PubMed2005

Radiofrequency catheter ablation of accessory pathways during pre-excited atrial fibrillation: acute success rate and long-term clinical follow-up results as compared to those patients undergoing successful catheter ablation during sinus rhythm.

The onset of recurrent or sustained atrial fibrillation (AF) is common during electrophysiological (EP) studies of accessory pathways (AP). We report our experience in patients with Wolff-Parkinson-White (WPW) syndrome in whom AF with rapid antegrade conduction over the AP occurred during an EP study and mapping and ablation were done during sustained AF, as compared to patients ablated during sinus rhythm. The study group consisted of 18 patients (group 1) with WPW syndrome who underwent catheter ablation during pre-excited AF. Two hundred and sixty-three patients, comparable for clinical characteristics, whose manifest APs were ablated under sinus rhythm formed the control group (group 2). Bipolar electrogram criteria recorded from the ablation catheter showing early ventricular activation relative to the delta wave on the surface ECG and AP potentials preceding the onset of ventricular activation were used as targets for ablation. Clinically documented atrial fibrillation was significantly more frequent and antegrade ERP of AP was significantly shorter in group 1 than in group 2 (39% vs 14%, P=0.014 and 268+/-37 vs 283+/-16, P<0.001, respectively). Procedure-related variables, acute success rates (17/18 [94%] in group 1, 251/263 [95%] in group 2; P>0.05) and late recurrence rates (0/18 [0%] in group 1 vs 5/263 [2%] in group 2; P>0.05) during a mean follow-up of 25+/-9 months (range 8-52 months) did not differ significantly. Our results show that both right- and left-sided accessory pathways can be mapped and ablated safely during pre-excited AF without delay, and that acute success and recurrence rates and long-term follow-up results are similar to those of pathways ablated during sinus rhythm.

Adolescent↗
PubMed2005

Atrioventricular nodal reentrant tachycardia with paroxysmal atrial fibrillation: clinical and electrophysiological features and predictors of atrial fibrillation recurrence following elimination of atrioventricular nodal reentrant tachycardia.

INTRODUCTION: Clinical and electrophysiological characteristics of patients with atrioventricular nodal reentrant tachycardia (AVNRT) and paroxysmal atrial fibrillation (AF) have not been studied in a large patient cohort. We aimed to define the clinical features and cardiac electrophysiological characteristics of these patients, and to examine the incidence and identify predictors of AF recurrences after elimination of AVNRT. METHODS AND RESULTS: Thirty-six patients with AVNRT and documented paroxysmal AF (Group 1) and 497 patients with AVNRT alone undergoing ablation in the same period (Group 2) were studied. There were no significant differences between groups regarding clinical features, except age, which was higher in Group 1 (p<0.001). Presence of atrial vulnerability (induction of AF lasting>30 seconds) and multiple AH jumps (>or=50 ms) before ablation were significantly more prevalent in Group 1 (p<0.001, p=0.010 respectively). During follow-up of 34 +/- 11 months, AF recurred in 10 patients (28%) in Group 1, while 2 patients in Group 2 (0.4%) developed paroxysmal AF (p<0.001). Univariate predictors of AF were: left atrial diameter>40 mm (p=0.001), presence of mitral or aortic calcification (p=0.003), atrial vulnerability after ablation (p=0.015) and valvular disease (p=0.042). However, independent predictors of AF recurrences were left atrial diameter>40 mm (p=0.002) and the presence of atrial vulnerability after ablation (p=0.034). CONCLUSION: In patients with both AVNRT and paroxysmal AF, the recurrence rate of AF after elimination of AVNRT is 28%. Left atrial diameter greater than 40 mm and atrial vulnerability after elimination of AVNRT are independent predictors of AF recurrences in the long term.

Adult↗
PubMed2005

Which Doppler parameters are load independent? A study in normal volunteers after blood donation.

OBJECTIVES: We sought to assess the effects of blood donation on different echocardiographic parameters in healthy volunteers. METHODS: A total of 101 healthy male volunteers were evaluated by echocardiography before and immediately after a 500-mL blood donation. In addition to traditional Doppler indices of left ventricular filling, Doppler tissue, color flow propagation, strain (epsilon), and epsilon rate were measured. RESULTS: There was a statistically significant decrease in mitral peak E and A values after blood donation (E wave 0.85 +/- 0.12 vs 0.79 +/- 0.14 cm/s, P = .01; A wave 0.65 +/- 0.10 vs 0.60 +/- 0.12 cm/s, P = .05). Mitral color flow propagation velocity was not affected (560 +/- 123 vs 571 +/- 132 mm/s, P = not significant). There were no significant differences in the Doppler tissue parameters of peak systolic, and early and late diastolic velocities after blood donation (Sm 13.5 +/- 4.6 vs 13.3 +/- 4.9 cm/s, P = not significant; Em 15.5 +/- 4.9 vs 15.9 +/- 5.1 cm/s, P = not significant; and Am 14.1 +/- 3.9 vs 14.1 +/- 3.5 cm/s, P = not significant, respectively). The peak systolic decreased significantly (-28 +/- 8% vs -21 +/- 4%, P = .03) whereas the peak systolic rate was not affected (1.5 +/- 0.35 vs 1.4 +/- 0.40 s(-1), P = not significant). CONCLUSION: In healthy male volunteers, preload reduction induced by a 500-mL blood donation does not affect the color propagation velocity, rate, and Doppler tissue velocities.

Adult↗
PubMed2005

Doxorubicin-induced second degree and complete atrioventricular block.

Doxorubicin is one of the most effective chemotherapeutic agents used in the treatment of malignancies. Cardiotoxicity is the most important dose-limiting toxicity of doxorubicin. Although cardiomyopathy is the most well known side effect of doxorubicin, it usually occurs many years after the treatment and relates to cumulative doxorubicin dosage. Another form of doxorubicin cardiotoxicity is arrhythmia which may occur at any time and after any dosage. However, doxorubicin-induced arrhythmia is rarely a life-threatening side effect. In this report, we present a case in which there were doxorubicin-induced life-threatening arrhythmias.

Adult↗
PubMed2005

Atrioventricular nodal reentrant tachycardia ablated from left atrial septum: clinical and electrophysiological characteristics and long-term follow-up results as compared to conventional right-sided ablation.

Radiofrequency catheter ablation or modification of the slow pathway is almost always performed on the right atrial side of the interatrial septum, however, this is not possible in rare cases. We evaluated the clinical and electrophysiological characteristics and long-term follow-up results of patients whose AVNRT could only be ablated from the left posterior atrial septum after repeated unsuccessful attempts on the right atrial side and to observe if they differ from those undergoing ablation with the conventional right-sided approach. Of 587 cases with symptomatic typical AVNRT, 9 patients (1.5%) in whom RF energy delivered to the right atrial septum with the integrated approach failed to ablate or modify the slow pathway were enrolled in the study group (group 1) while the others served as controls (group 2). There was no significant difference between the groups regarding clinical characteristics, dual AV nodal physiology, sinus cycle lengths, AH and HV intervals, procedural complication rates, or recurrence rates in the mean follow-up duration of 34 +/- 11 months. Only tachycardia cycle length (TCL) was significantly higher in group 1 than in group 2, which was mainly due to the difference in AH intervals (P < 0.001 for both). Slow pathway ablation was performed at the posteroseptal aspect of the mitral annulus in 6 and the midseptal aspect in 2 cases. In 1 case, attempts at ablation on the left atrial septum also failed. When the conventional right-sided approach fails to ablate or modify the slow pathway conduction, left-sided ablation can safely and effectively be employed, with success rates and long-term follow-up results comparable to the conventional right-sided approach.

Adult↗
PubMed2005

Ventriculatrial block during atrioventricular nodal reentrant tachycardia suggesting existence of an upper common pathway.

Studies on the mechanisms of atrioventricular nodal reentrant tachycardia (AVNRT) have yet to clarify whether the slow and fast pathways connect directly with the atria or via an upper common pathway. Although a "final common pathway" connecting the slow and fast pathways to the proximal His bundle was thought to be part of the reentrant circuit, debate on the presence of an upper common pathway continues. We report a case of AVNRT continuing despite the occurrence of ventriculoatrial block, thus supporting the existence of an upper common pathway.

Adult↗
PubMed2005

Successful catheter ablation of a right-sided accessory pathway in a child with interruption of the inferior vena cava and azygos continuation.

Azygos continuation is seen in 0.6% of patients with congenital heart disease. The major significance of this anomaly lies in its association with complex cardiac defects and the technical difficulty that can accompany cardiac catheterization. We report our experience with successful catheter ablation of a right posteroseptal concealed accessory pathway in a 6-year-old boy with infrahepatic interruption of the inferior vena cava and azygos continuation.

Azygos Vein↗