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Dive into the research topics where Mehmet Akkaya is active.

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Featured researches published by Mehmet Akkaya.


Cardiology Journal | 2013

Predictive value of atrial electromechanical delay for atrial fibrillation recurrence

Hasan Ari; Selma Arı; Mehmet Akkaya; Cihan Aydin; Nadir Emlek; O. Yaşar Sarigül; Seçkin Çetinkaya; Tahsin Bozat; Muhammet Şentürk; Kemal Karaagac; Mehmet Melek; Mustafa Yilmaz

BACKGROUND We investigated the predictive value of atrial electromechanical delay (AEMD) for recurrence of atrial fibrillation (AF) at 1-month after cardioversion. METHODS Seventy-seven patients with persistent AF were evaluated and finally 50 patients (12 men, 38 women) were included. All patients underwent transthoracic electrical DC cardioversion under amiodarone treatment. AEMD was measured as the time interval from the onset of the P wave on electrogram (ECG) to the beginning of late diastolic wave (Am) from the ventricular annulus and atrial walls on tissue Doppler imaging, in the apical 4-chamber view 24 h after cardiversion. P wave maximum-duration (Pmax), P wave minimum-duration (Pmin) and P wave dispersion-duration (Pdis) were calculated on the 12-lead ECG at 24-h postcardioversion. We followed the heart rate and rhythm by 12-lead ECG at 24-h, 1-week and 1-month. RESULTS At 1-month follow-up after cardioversion, 28 (56%) patients were in sinus rhythm (SR), whereas 22 (44%) patients reverted to AF. The AEMD durations were longer in AF group than SR group (p < 0.001) and were signifi cantly correlated with Pmax and Pdis (p < 0.001 for both). For AF recurrence; duration of AF, left atrial (LA) diameter, maximum LA volume index, mitral A velocity and LA lateral AEMD were significant parameters in univariate-analysis, however LA lateral AEMD was the only significant parameter in multivariate-analysis (OR: 1.46; 95% CI 1.02-2.11; p = 0.03). CONCLUSIONS Our results suggest that AEMD is associated with an increased risk of recurrence of AF within 1-month. These data may have implications for the identification of patients who are most likely to experience substantial benefit from cardiversion therapy for AF.


Clinics | 2013

Early assessment of percutaneous coronary interventions for chronic total occlusions analyzed by novel echocardiographic techniques

Ercan Erdogan; Mehmet Akkaya; Ahmet Bacaksiz; Abdurrrahman Tasal; Osman Sonmez; Mehmet Ali Elbey; Seref Kul; Mehmet Akif Vatankulu; Murat Turfan; Omer Goktekin

OBJECTIVE: Successful revascularization of chronic total occlusions has been associated with improved left ventricular systolic function, reduced anginal symptoms, increased exercise capacity, and increased survival. This study was conducted to determine the impact of revascularization in chronic total occlusion on left ventricular function using novel echocardiographic techniques. METHODS: A total of 129 patients with chronic total occlusion who underwent revascularization between April 2011 and November 2012 were included in this study. Echocardiographic assessments with two-dimensional speckle tracking echocardiography and real-time three-dimensional echocardiography were performed before the procedure and one month after the procedure. The left ventricular ejection fraction, left ventricular volumes, and three-dimensional systolic dyssynchrony index were quantified. RESULTS: An immediate procedural success was obtained in 118 patients (91.5%). There were no acute or subacute stent thromboses during follow-up. The mean left ventricular ejection fraction significantly increased (p<0.001), while the left ventricular end-diastolic and end-systolic volumes significantly decreased (p = 0.001 and p<0.001, respectively). The three-dimensional systolic dyssynchrony index also decreased significantly (p<0.001). The global longitudinal strain showed a significant increase after successful revascularization (p<0.001). An increase in the global longitudinal strain was correlated with an increase in the left ventricular ejection fraction (r = 0.27, p = 0.02). The patients with a left ventricular ejection fraction ≥50% displayed a greater improvement in the global longitudinal strain, and the patients with diabetes showed less improvement. CONCLUSIONS: Using novel echocardiographic techniques, our results showed that restoring the coronary blood flow in chronic total occlusion patients reduces the left ventricular volumes and improves the left ventricular ejection fraction and the global longitudinal strain of hibernating myocardium.


Southern Medical Journal | 2010

Association of Thrombotic and Fibrinolytic Factors with Severity of Culprit Lesion in Patients with Acute Coronary Syndromes Without ST Elevation

Yasin Türker; Abdullah Dogan; Mehmet Ozaydin; Selcuk Kaya; Süleyman Önal; Mehmet Akkaya; Dogan Erdogan

Background: Increased procoagulant activity and/or impaired fibrinolysis contribute to the development and organization of thrombus, subsequently resulting in complete or incomplete obstruction in acute coronary syndromes (ACS). We investigated the relationship between culprit lesion severity and thrombotic and fibrinolytic parameters in patients who had non-ST elevation ACS (NSTE-ACS). Methods: This study included 95 consecutive patients with NSTE-ACS. All patients underwent coronary angiography within the first 72 hours depending on the clinical situation. Stenosis ≥50% in the coronary artery was considered significant. NSTE-ACS patients were then divided into two groups: patients with critical stenosis (n = 53) and patients with noncritical stenosis (n = 35). Plasma levels of D-dimer, fibrinogen, thrombin-antithrombin III complex (TAT), and prothrombin fragment 1 + 2 (PF 1 + 2) were measured. Results: D-dimer (338 ± 192 vs. 190 ± 170 &mgr;g/dL, P < 0.001), TAT (4.4 ± 2.0 vs. 1.2 ± 0.7 ng/mL, P < 0.001), and PF 1 + 2 (1.6 ± 0.6 vs. 0.7 ± 0.3 nmol/L) levels were significantly higher in the critical stenosis group as compared to the noncritical stenosis group. However, fibrinogen levels were similar in both groups. The levels of TAT (r = 0.76, P < 0.001) and PF 1 + 2 (r = 0.73, P < 0.001) were correlated with the culprit lesion severity, but D-dimer and fibrinogen levels were not. Thrombolysis in myocardial infarction flow grades were also correlated with TAT (r = −0.42, P < 0.001) and PF 1 + 2 (r = −0.40, P < 0.001). Conclusion: The severity of culprit lesion may be associated with plasma D-dimer, TAT, and PF 1 + 2 levels in NSTE-ACS patients. These prothrombotic factors may have a role in the development of significant stenosis in the NSTE-ACS setting.


The Anatolian journal of cardiology | 2013

Subclinical left ventricular dysfunction in women with polycystic ovary syndrome: an observational study

Ercan Erdogan; Mehmet Akkaya; Ahmet Bacaksiz; Abdurrahman Tasal; Murat Turfan; Seref Kul; Osman Sonmez; Mehmet Akif Vatankulu; Gokhan Ertas; Gonca Batmaz; Mehmet Ergelen; Huseyin Uyarel; Omer Goktekin

OBJECTIVE Cardiac involvement has been increasingly recognized in patients with polycystic ovary syndrome (PCOS). Identification of the earliest asymptomatic impairment of left ventricular (LV) performance may be important in preventing progression to overt heart failure. Our aim was to investigate LV function with different echocardiographic techniques in patients with PCOS. METHODS Thirty patients with PCOS and 30 age and body mass index matched healthy subjects were enrolled to this cross-sectional observational study. All subjects underwent echocardiography for assessment of resting LV function as well as two-dimensional speckle tracking echocardiography (2D-STE) and real-time three-dimensional echocardiography (3D-Echo). Global longitudinal strain (GLS) was calculated from 3 standard apical views using 2D-STE. Student t-test, chi-square test, Pearsons, and Spearmans correlation analysis were used for statistical analysis. RESULTS The early mitral inflow deceleration time (DT), isovolumetric relaxation time (IVRT) and E/Em ratio were increased in the PCOS group (p<0.05 for all). Waist-to-hip ratio, fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR) and low-density lipoprotein (LDL) levels were higher in PCOS group (p<0.05 for all). Significant correlation was observed between DT, IVRT and insulin value, HOMA-IR (p<0.05 for all). On 3D-Echo evaluation, none of the patients in both groups had LV systolic dysfunction with comparable LV ejection fraction and LV volumes. 2D-STE showed that GLS was significantly reduced in the PCOS group compared to control group (-16.78 ± 0.56% vs. -18.36 ± 1.04%, p<0.001). The GLS was found to be negatively correlated with waist-to-hip ratio and LDL values (p<0.05 for all). CONCLUSION These results indicate that PCOS may be related to impaired LV systolic function detected by 2D-STE. In addition, PCOS may lead to diastolic dysfunction. Reduced GLS might be an early indicator of cardiac involvement in this patient population.


Medical Science Monitor | 2013

Short-term effect of percutaneous recanalization of chronic total occlusions on QT dispersion and heart rate variability parameters

Ercan Erdogan; Mehmet Akkaya; Ahmet Bacaksiz; Abdurrahman Tasal; Osman Sonmez; Emin Asoglu; Seref Kul; Musa Sahin; Murat Turfan; Mehmet Akif Vatankulu; Omer Goktekin

Background QT dispersion (QTd), which is a measure of inhomogeneity of myocardial repolarization, increases following impaired myocardial perfusion. Its prolongation may provide a suitable substrate for life-threatening ventricular arrhythmias. We investigated the changes in QTd and heart rate variability (HRV) parameters after successful coronary artery revascularization in a patient with chronic total occlusions (CTO). Material/Methods This study included 139 successfully revascularized CTO patients (118 men, 21 women, mean age 58.3±9.6 years). QTd was measured from a 12-lead electrocardiogram and was defined as the difference between maximum and minimum QT interval. HRV analyses of all subjects were obtained. Frequency domain (LF: HF) and time domain (SDNN, pNN50, and rMSSD) parameters were analyzed. QT intervals were also corrected for heart rate using Bazett’s formula, and the corrected QT interval dispersion (QTcd) was then calculated. All measurements were made before and after percutaneous coronary intervention (PCI). Results Both QTd and QTcd showed significant improvement following successful revascularization of CTO (55.83±14.79 to 38.87±11.69; p<0.001 and 61.02±16.28 to 42.92±13.41; p<0.001). The revascularization of LAD (n=38), Cx (n=28) and RCA (n=73) resulted in decrease in HRV indices, including SDDN, rMSSD, and pNN50, but none of the variables reached statistical significance. Conclusions Successful revascularization of CTO may result in improvement in regional heterogeneity of myocardial repolarization, evidenced as decreased QTcd after the PCI. The revascularization in CTO lesions does not seem to have a significant impact on HRV.


The Anatolian journal of cardiology | 2012

[The effect of hemodialysis on right ventricular functions in patients with end-stage renal failure].

Mehmet Akkaya; Ercan Erdogan; Saim Sağ; Hasan Ari; Yasin Türker; Mustafa Yılmaz

OBJECTIVE The aim of this study was to evaluate the effects of hemodialysis (HD) on right ventricular echocardiographic parameters in patients with end-stage renal failure (ESRF). METHODS Forty-three uremic patients who underwent echocardiography before and 30 minutes after dialysis included in this prospective observational study. Right ventricular systolic function was evaluated using tricuspid annular plane systolic excursion (TAPSE) by M-mode echocardiography and tricuspid lateral annular systolic velocity (Sa) by tissue Doppler echocardiography whereas diastolic function was evaluated using tricuspid early (E) and late (A) diastolic flow velocities by conventional and tricuspid lateral annular early (Ea) and late (Aa) diastolic velocities by tissue Doppler echocardiography. Myocardial performance index was taken as an indicator of global functions. Paired t test or Wilcoxon test were used for statistical analysis where appropriate. RESULTS E decreased significantly (68 ± 13 cm/s and 56 ± 12 cm/s before and after HD, respectively; p<0.0001) but A did not (p=0.797).TAPSE was 1.84 ± 0.34 cm before HD and showed a significant increase to 2.03 ± 0.20 cm after HD (p=0.006). Right ventricular MPI, Sa and Aa did not change significantly by dialysis (p=0.504; p=0.118 and p=0.150 respectively) whereas Ea decreased to 8.8 ± 2.5 cm/s from 11.3 ± 3.4 cm/s (p<0.001). Ea/Aa ratio also decreased significantly to 0.69 ± 0.35 from 0.84 ± 0.44 with HD (p=0.007). CONCLUSION The results of this study indicates that parameters of right ventricular systolic function such as Sa and MPI are independent of preload whereas the conventional and tissue Doppler parameters of right ventricular diastolic function are preload dependent in patients with end-stage renal failure who undergo regular hemodialysis.


Cardiology Journal | 2012

Short-term outcome of early electrical cardioversion for atrial fibrillation in hyperthyroid versus euthyroid patients*

Hasan Ari; Muhammet Gürdoğan; Ercan Erdogan; Selma Arı; Yusuf Ata; Selma Kenar Tiryakioglu; Mehmet Akkaya; Vedat Koca; Tahsin Bozat

BACKGROUND Atrial fibrillation (AF) is the most common cardiac complication of hyperthyroidism. The influence of the time of cardioversion on hyperthyroidism-induced AF remains unclear. The aim of this study was to compare short-term outcomes of early electrical cardioversion for AF in hyperthyroid and euthyroid patients. METHODS AND RESULTS Sixty-seven subjects with persistent AF (duration, 10 days-12 months) were divided into two groups according to thyroid function: Euthyroid (Group 1, n = 36, female/male: 23/13, mean age: 61.77 ± 10.45 years) and hyperthyroid (Group 2, n = 31, female/male: 10/21, mean age: 65.43 ± 6.40 years). Two patients were excluded for unsuccessful cardioversion (one in each group). In Group 2, 19 patients had clinical and 11 had subclinical hyperthyroidism. Following transthoracic and transesophageal echocardiography, cardioversion was performed until the highest energy was reached (270 J) or until sinus rhythm was achieved. AF recurrence was detected in 13 of 35 patients (37.1%) in Group 1 and in 11 of 30 patients (36.9%) in Group 2 (p = 0.96) at one month. Recurrence rate was higher in the clinical hyperthyroid patients than in the subclinical hyperthyroid patients (52.6% vs 9.1%, p = 0.021), but neither the clinical nor the subclinical hyperthyroid subgroups were significantly different from Group 1 in terms of recurrence rate (p = 0.27 and p = 0.13, respectively). CONCLUSIONS Electrical cardioversion should be performed for patients with persistent AF and hyperthyroidism as soon as possible.


Revista Portuguesa De Pneumologia | 2014

High levels of high-sensitivity C-reactive protein and uric acid can predict disease severity in patients with mitral regurgitation

Yasin Türker; İsmail Ekinözü; Yasemin Turker; Mehmet Akkaya

INTRODUCTION Both high-sensitivity CRP (hs-CRP) and uric acid (UA) levels are known to be increased in heart failure patients and are associated with poorer functional capacity and adverse outcome. The role of these markers in patients with mitral regurgitation (MR) is less clear. The aim of this study was to assess the relationship between hs-CRP, UA and organic MR. We also assessed whether hs-CRP and UA levels are correlated with symptoms of MR, severity of MR, LV remodeling and outcome during follow-up. METHODS A total of 200 consecutive patients (87 men [43.5%]; mean age 61.6±12.5 years) with moderate or severe isolated and organic MR were included in the study. All the patients were assessed clinically and were managed and treated with standard medical therapy according to evidence-based practice guidelines. Patients were categorized according to New York Heart Association (NYHA) functional class. We assessed and graded the severity of MR using a multiparametric approach. hs-CRP was measured with chemiluminescent immunometric assay using an IMMULITE® 1000 autoanalyzer (Siemens, Germany). Serum UA levels were analyzed using a Cobas® 6000 autoanalyzer (Roche Diagnostics, Mannheim, Germany). RESULTS Mean UA levels increased significantly with NYHA class: 4.46±1.58 mg/dl for patients in NYHA class I, 5.91±1.69 mg/dl for class II, 6.31±2.16 mg/dl for class III and 8.86±3.17 mg/dl for class IV (p<0.001). Mean UA levels also increased significantly with increased severity of MR (moderate 5.62±1.9 mg/dl, moderate to severe 5.56±1.2 mg/dl, severe 7.38±3.4 mg/dl, p<0.001). There was a significant correlation between UA level and left ventricular end-diastolic diameter (r=0.40; p<0.001), left ventricular end-systolic diameter (r=0.297; p=0.001) and left ventricular ejection fraction (LVEF) (r=0.195, p=0.036), whereas hs-CRP was not correlated with these parameters. In multivariate Cox proportional hazards analysis LVEF, NYHA class and UA levels were the only independent predictors of death. CONCLUSION UA and hs-CRP levels can help identify patients with asymptomatic moderate or severe mitral regurgitation. UA levels may be useful to assess the extent of left ventricular remodeling and in the optimal timing of mitral valve surgery in certain subsets of patients.


Gynecological Endocrinology | 2013

Polycystic ovary syndrome is associated with P-wave prolongation and increased P-wave dispersion

Ercan Erdogan; Mehmet Akkaya; Murat Turfan; Gonca Batmaz; Ahmet Bacaksiz; Abdurrahman Tasal; Muzaffer Ilhan; Seref Kul; Osman Sonmez; Mehmet Akif Vatankulu; Ertugrul Tasan

Abstract Background: The polycystic ovary syndrome (PCOS) is associated with various cardiac manifestations including cardiac arrhythmias. P-wave dispersion (Pdis) is an appealing marker for predicting the risk of developing atrial arrhythmias. The purpose of this study was to evaluate P-wave durations and Pdis in patients with PCOS. Methods: Forty adult patients with PCOS and 46 age- and sex-matched healthy individuals were included in this study. P-wave maximum duration (Pmax) and P-wave minimum duration (Pmin) were calculated on the 12-lead electrocardiogram, and the difference between the Pmax and the Pmin was defined as Pdis. All individuals also underwent transthoracic echocardiographic evaluation. Results: Pmax and Pdis were significantly higher in patients with PCOS compared with controls (p = 0.007, p < 0.001, respectively). There was no difference in Pmin duration between both the groups (p = 0.2). Waist-to-hip ratio, insulin and homeostasis model assessment of insulin resistance (HOMA-IR) were higher in the PCOS group. Early mitral inflow deceleration time (DT) (p < 0.001) and isovolumetric relaxation time (p = 0.003) were longer in PCOS group. Waist-to-hip ratio, DT, E/A ratio and diastolic blood pressure correlated with Pdis. Conclusions: Patients with PCOS have prolonged Pmax and Pdis. The increase in those parameters may be an indicator for identification of patients at increased risk of atrial fibrillation.


Annales D Endocrinologie | 2013

Electrocardiographic and echocardiographic evidence of myocardial impairment in patients with overt hypothyroidism.

Ercan Erdogan; Mehmet Akkaya; Ahmet Bacaksiz; Abdurrrahman Tasal; Muzaffer Ilhan; Seref Kul; Emin Asoglu; Murat Turfan; Osman Sonmez; Ertugrul Tasan

OBJECTIVE Our aim was to evaluate cardiac function and myocardial contractility in patients with overt hypothyroidism using two-dimensional speckle tracking echocardiography (2D-STE) strain imaging and real-time three-dimensional echocardiography (RT3DE) and compare the changes at one month after starting the treatment. We also compared the P wave dispersion (Pdis) in patients with and without hypothyroidism. SUBJECTS AND METHODS Forty-one patients with overt hypothyroidism and forty age- and body mass index-matched healthy subjects underwent conventional echocardiography, RT3DE and 2D-STE for assessment of resting LV function. Electrocardiography (ECG) recordings were obtained and the P wave parameters were calculated. Measurements of RT3DE volumes and ejection fraction (EF) were performed. Global longitudinal strain (GLS) was calculated from 3 standard apical views using 2D-STE. RESULTS Patients with overt hypothyroidism had significantly longer isovolumic contraction time (P<0.001), deceleration time (P<0.001) and isovolumic relaxation time (P<0.001). On RT3DE evaluation, none of the patients in both groups had LV systolic dysfunction with comparable LVEF and LV volumes. However, speckle tracking analysis showed that GLS was significantly reduced in the overt hypothyroidism group compared to control group (P<0.001). At one month follow-up after the treatment, GLS significantly improved in overt hypothyroidism group (P<0.001). Patients in the overt hypothyroidism group had increased Pdis compared to control group (P=0.02). CONCLUSIONS Overt hypothyroidism may be related to impairment of LV longitudinal myocardial function, and 2D-STE is useful for the detection of early impairment. Successful treatment of overt hypothyroidism has a beneficial effect on cardiac functions. In addition, overt hypothyroidism has increased risk for atrial arrhythmias due to high Pdis value.

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Seref Kul

Foundation University

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