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Biomedical subjects

Ilknur Can

Publications and source records attributed to Ilknur Can.

14 recordsLinked to original sources
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

Correlation of tissue selectin expression and hemodynamic parameters in rheumatic mitral valve disease.

BACKGROUND AND AIM OF THE STUDY: The study aim was to examine tissue expression of the adhesion molecules E-selectin and P-selectin on atrial, valvular and atrial myocardial blood vessel endothelium in patients with rheumatic mitral stenosis, and to investigate whether such expression was correlated with hemodynamics. METHODS: Thirteen patients (eight women, five men; mean age 51 +/- 10 years) with severe rheumatic mitral stenosis who underwent mitral valve replacement surgery were examined on preoperative day 1, using cardiac catheterization and echocardiography. Specimens from the mitral valve and left atrium of each patient were evaluated for CD 62E and CD 62P expression using indirect immunoperoxidase and immunofluorescence techniques RESULTS: A great majority of patients presented E and/or P selectin expression of variable intensity on atrial, valvular and atrial myocardial blood vessel endothelium. A more diffuse and stronger reaction for CD 62P was noted compared to that for CD 62E. The left ventricular end-diastolic diameter and left atrial diameter were positively correlated with endocardial CD 62P and CD 62E expression. Right atrial pressure was also strongly and positively correlated with endocardial expression of CD 62E (r = 0.80, p 0.03) and CD 62P (r = 0.8, p = 0.02). CONCLUSION: Marked tissue expression of CD 62E and CD 62P was identified on atrial, valvular and atrial myocardial blood vessel endothelium. Moreover, the degree of expression of adhesion molecules was significantly correlated with the left atrial and left ventricular chamber diameters, as well as right atrial pressure.

Adult↗
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

Doppler tissue evaluation of intra-atrial and interatrial electromechanical delay and comparison with P-wave dispersion in patients with mitral stenosis.

OBJECTIVE: The aim of our study was to: (1) measure atrial electromechanical delay in patients with mitral stenosis (MS) and in a control group; (2) find the echocardiographic parameters that affect atrial electromechanical delay; and (3) examine the correlation between atrial electromechanical delay and P-wave dispersion (PWD). METHODS: A total of 25 patients with pure MS (age 43 +/- 10 years; 18 women, 7 men) and 16 control subjects (age 41 +/- 8 years; 9 women, 7 men) were studied. Interatrial and intra-atrial electromechanical delay was measured with Doppler tissue echocardiography. From the 12-lead electrocardiograms, PWD was calculated. RESULTS: Interatrial electromechanical delay was 71.2 +/- 33 in the MS group and 40.5 +/- 21.0 in the control group (P = .01). In the MS group, PWD was 50 +/- 7 and in the control group it was 29 +/- 5 (P = .03). A positive correlation was detected between interatrial electromechanical delay and PWD (r = 0.6, P = .03). CONCLUSION: This study shows that interatrial electromechanical delay gets longer in MS and is correlated with PWD. Atrial electromechanical delay is related with left atrial size but not with severity of MS.

Adult↗
PubMed2004

Atrioventricular nodal reentrant tachycardia with multiple discontinuities in the atrioventricular node conduction curve: immediate success rates of radiofrequency ablation and long-term clinical follow-up results as compared to patients with single or no AH-jumps.

BACKGROUND: Some patients with atrioventricular nodal reentrant tachycardia (AVNRT) demonstrate multiple discontinuities (AH jump) in their antegrade AV node conduction curves. We evaluated and compared the immediate success rates, procedure-related complications, long-term clinical follow-up results and recurrence rates after slow pathway ablation in patients with multiple versus single or no AH jumps. METHODS: The study group consists of 278 consecutive patients (mean age 36.6 +/- 15.7) who underwent ablation for typical AVNRT, divided into three categories according to the number of AH jumps (>/=50 ms) before ablation: Group-1 consisted of 63 patients (23%) with continuous AV node function curves; Group-2 of 183 patients (66%) with a single jump and Group-3 of 32 (12%) patients showing more than one AH jumps. RESULTS: Age was significantly higher in Group-3 as compared to Group-1 (43 +/- 18 years vs. 34 +/- 16 years, p = 0.020). The electrophysiological features of AVNRT did not differ among groups. Before ablation, the maximum AH interval was significantly longer in Group-3 as compared to Groups-1 and -2 ( p < 0.001 for both). AV node antegrade ERP was significantly shorter in Group-3 than in Group-2, both before and after ablation ( p < 0.050 for both). AV node Wenckebach cycle length (WCL) was shorter in Group-3 as compared to both Groups-1 and -2, before and after ablation ( p < 0.050 for all). AV node WCL was prolonged significantly in all groups after ablation ( p < 0.001 for all). Residual dual pathways were present in 37 of 278 patients (13%) after ablation and were significantly more frequent in Group-3 than Group-2 (31% vs. 15%, p = 0.023). CONCLUSIONS: Patients with multiple AH jumps are older and more often have residual dual atrioventricular nodal pathway physiology after successful ablation but these features do not affect the immediate and long-term success rates of slow pathway ablation as compared to patients with single or no AH jumps.

Adolescent↗
PubMed2004

Left ventricular long-axis function is reduced in patients with rheumatic mitral stenosis.

Left ventricular long-axis function evaluated by M-mode or tissue Doppler echocardiography has been shown to be useful indexes of left ventricular systolic function; however it has not been evaluated in patients with mitral stenosis. We examined the left ventricular long-axis function of the patients with pure mitral stenosis and normal global systolic function as assessed by fractional shortening of the left ventricle (LV). Fifty-two patients with pure mitral stenosis and twenty-two healthy controls were evaluated by echocardiography. Although there was no statistically significant difference in global systolic function, M-mode derived systolic motion of the septal side and (12 +/- 3 vs 14.4 +/- 1.5 mm, P = 0.016) the lateral side of mitral annulus (13.2 +/- 3 vs 16.8 +/- 2 mm, P = 0.001) were both significantly lower in the patients with mitral stenosis than control subjects. Similarly tissue Doppler systolic velocity of the septal annulus (7.6 +/- 1.1 vs 10.4 +/- 3.2 cm/s, P = 0.03) and lateral mitral annulus (7.6 +/- 1.1 vs 10.4 +/- 3.2 cm/s, P = 0.003) were also significantly lower in patients with mitral stenosis than in controls. There was a statistically significant correlation between septal annular motion and annular velocity (r = 0.643, P = 0.002). Septal annular motion and annular velocity were also correlated with left atrial ejection fraction (r = 0.338, P = 0.005 and r = 0.676, P = 0.001, respectively). Thus, patients with mitral stenosis had significantly impaired long-axis function evaluated by M-mode or tissue Doppler echocardiography despite normal global systolic function.

Adult↗
PubMed2004

Increased P wave dispersion and maximum P wave duration after hemodialysis.

BACKGROUND: Atrial fibrillation is a frequent arrhythmia in patients undergoing hemodialysis. The consequences of hemodialysis on P wave durations and P wave dispersion have not been fully understood. The objective of this study was to study the effect of dialysis on P wave maximum (Pmax), P wave minimum (Pmin), and P wave dispersion (Pd). METHODS: We studied Pmax, Pmin, and Pd in 32 patients (17 men and 15 women, mean age 54 +/- 18 years) with chronic renal failure undergoing hemodialysis. The difference between maximum and minimum P wave duration was calculated and defined as P wave dispersion (Pd= Pmax- Pmin). RESULTS: There was a significant increase in Pmax at the end of dialysis compared to the beginning (98 +/- 13 ms vs. 125 +/- 12 ms, P < 0.001). Pmin did not show any significant change (71 +/- 11 ms vs. 73 +/- 10 ms, P = 0.42). Pd was significantly increased at the end of dialysis (27 +/- 9 ms vs. 52 +/- 11 ms, P < 0.001). There was a negative correlation between serum potassium, magnesium, phosphate, blood urea nitrogen, and creatinin at the end of dialysis and Pmax and Pd, respectively (P < 0.05). A weak positive correlation was found between serum calcium, bicarbonate at the end of dialysis and Pmax and Pd (P < 0.05). CONCLUSION: Hemodialysis ends with significant increase in P wave maximum duration and P wave dispersion, which might be responsible for the increased occurrence of atrial fibrillation in these groups of patients.

Atrial Fibrillation↗
PubMed2003

Detection of patients with hypertrophic cardiomyopathy at risk for paroxysmal atrial fibrillation during sinus rhythm by P-wave dispersion.

BACKGROUND: Paroxysmal atrial fibrillation (PAF) in hypertrophic cardiomyopathy (HCM) is associated with poor prognosis. Previous studies have shown good correlation between P-wave dispersion (Pd) and occurrence of PAF. However, Pd in patients with HCM for predicting PAF has not been studied. HYPOTHESIS: The aim of the study was to determine whether Pd could identify patients with HCM who are likely to suffer from PAF. METHODS: Twenty-two patients with HCM with a history of PAF (Group 1) and 26 patients with HCM without a history of PAF (Group 2) were studied. Maximum (Pmax) and minimum (Pmin) P-wave durations, as well as P-wave dispersion (Pd = Pmax - Pmin) were calculated from 12-lead surface electrocardiograms (ECG). RESULTS: P-wave dispersion was significantly different between the groups (Group 1: 55 +/- 6 ms vs. Group 2: 37 +/- 8 ms; p<0.001), while Pmax (Group 1: 134 +/- 11 ms vs. Group 2: 128 +/- 13 ms; p = 0.06) and Pmin (Group 1: 78 +/- 9 ms vs. Group 2: 81 +/- 7 ms; p = 0.07) was not significantly different. Patients with a history of PAF had higher left atrial diameter than the patients without PAF (Group 1: 52 +/- 8 mm vs. Group 2: 48 +/- 10 mm; p = 0.02). A cut-off value of 46 ms for Pd had a sensitivity of 76% and a specificity of 82% in discriminating between patients with and without PAF. CONCLUSION: This study suggests that P-wave dispersion could identify patients with HCM who are likely to develop PAF.

Adult↗
PubMed2003

Seasonal variability of QT dispersion in healthy young males.

BACKGROUND: There are few data related to the seasonal influences on the QT dispersion. METHODS: We analyzed the effects of seasons on QT dispersion in a large group of healthy young males. We studied the seasonal variability of QT dispersion in 523 healthy male subjects aged 22 +/- 4 years (ranging from 20 to 26). Four seasonal 12-lead resting electrocardiograms (ECGs) recorded at double amplitude were performed at 25 mm/s at intervals of 3 months. Subsequent ECGs were recorded within 1 hour of the reference winter recording. QT dispersion was defined as the difference between the longest and the shortest mean QT intervals. RESULTS: There was a significant seasonal variation in QT dispersion (P = 0.001), with the largest QT dispersion in winter (71 +/- 18 ms) and the smallest one in spring (43 +/- 19). CONCLUSION: There exists a significant seasonal variation in QT dispersion of healthy subjects and such variability should be taken into consideration in the evaluation process of QT dispersion.

Adult↗
PubMed2002

Physiological mechanisms influencing cardiac repolarization and QT interval.

Cardiac repolarization primarily results from activation of outward currents carried by potassium ions which are heterogeneously distributed throughout the myocardial layers which can lead to changes in various phases of cardiac cycle. QT interval is a reflector of cardiac repolarization and can be influenced by heart rate, autonomic nervous system, gender and time of the day. T wave alternans (TWA), specifically the discordant pattern is a feature of abnormal cardiac repolarization that can be used as a predictor of ventricular arrhythmias.

Arrhythmias, Cardiac↗
PubMed2002

Seasonal variation of P-wave dispersion in healthy subjects.

We studied the seasonal variability of P dispersion in 523 healthy male patients, aged 22 +/- 4 years (range, 20-26). Four seasonal 12-lead resting electrocardiograms were recorded at 2 mV/cm standardization and at 50 mm/s paper speed at intervals of three months. Electrocardiograms were recorded between the hours 10 to 12 AM. The difference between the maximum P-wave duration and minimum P-wave duration was calculated and defined as "P dispersion." There was a significant seasonal variation in the maximum P-wave duration (P = .001) and P dispersion (P = .001), with the longest maximum P-wave duration (121 +/- 16 ms) and P dispersion (41 +/- 7 ms) observed in winter and the shortest maximum P-wave duration (106 +/- 15 ms) and P dispersion (24 +/- 8 ms) observed in summer. The minimum P-wave duration did not show any significant seasonal variation. In conclusion, there exists a significant seasonal variation in the maximum P-wave duration and P dispersion in healthy patients. Seasonal variation of P dispersion resulted from the significant variation of maximum P-wave duration.

Adult↗