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Ahmet Temizhan

Publications and source records attributed to Ahmet Temizhan.

9 recordsLinked to original sources
PubMed2005

The effects of mobile phones on pacemaker function.

OBJECTIVES: The electromagnetic field generated by different systems have well-recognized adverse effects on pacemaker functions. The aim of this study is to evaluate the adverse effects of mobile phones on pacemaker functions. METHODS AND RESULTS: A total of 679 patients with permanent pacemakers were enrolled in this study. The study was performed in two steps. Pacemaker lead polarity was unipolar in the first step and bipolar in the second step. Pacemaker sensitivity was first at nominal values, it was then reduced to the minimal value for that pacemaker and tested again. Two mobile phones were symmetrically located on both sides of the pacemaker pocket with the antennas being equidistant at 50, 30, 20 and 10 cm and in close contact with the pocket. The tests were performed when both mobiles were opened, on stand-by, were receiving a call, during the call and were closed. Thirty-seven patients with pacemakers were adversely affected (5.5%) (33 VVI-R pacemakers were converted to asynchronous mode, and 3 were inhibited, 1 DDD-R pacemaker developed ventricular triggering). When the lead polarity was unipolar, the rate of adverse effect was higher when compared to the bipolar state (4.12% and 1.40%, p<0.01). The increase in sensitivity was not an independent factor on the rate of being affected (p>0.05). The rate of observing an adverse effect increased as the pacemaker got older (p<0.05). CONCLUSIONS: Mobile phones might have adverse effects on pacemaker functions under certain conditions. This does not result in any symptoms other than the inhibition of pacemakers, and pacemaker functions return to normal when the mobile phones are removed away from the patient.

Aged↗
PubMed2004

The influence of aldosterone on the development of left ventricular geometry and hypertrophy in patients with essential hypertension.

The identification of risk factors for the initiation of left ventricle hypertrophy (LVH), which is an independent risk factor for cardiovascular mortality and morbidity in hypertensive patients, is very important. The objective of the present study was to identify the relationship of aldosterone with LVH and different geometrical patterns of left ventricle that develop in patients with essential hypertension. A total of 83 patients with essential hypertension (44 females, mean age, 51 +/- 8 years, 39 males, mean age, 57 +/- 10 years) were included in this study. Thirty-two had LVH. When evaluated according to the geometrical patterns of LVH, 18 patients had concentric LVH, 14 had eccentric LVH, and 17 had concentric remodeling. Thirty-four patients had normal left ventricle geometry. Two weeks after the cessation of antihypertensive medications, sodium, potassium, and proteinuria in 24-hour urine samples and plasma aldosterone levels and plasma renin activity were measured. Plasma aldosterone levels of the patients with LVH were found to be significantly higher (9.92 +/- 6.34 ng/dL versus 5.83 +/- 3.5 ng/dL, P < 0.01). The difference between plasma renin activities was not statistically significant. Linear regression analysis revealed that plasma aldosterone level and age were independent parameters increasing left ventricle mass index. The plasma aldosterone levels of patients with concentric hypertrophy of the left ventricle were significantly higher than those of patients with normal geometry and concentric remodeling. There was no significant difference between plasma renin activities. Twenty-four hour urine protein concentrations of the patients with LVH were found to be significantly higher and sodium to be significantly lower. Plasma aldosterone levels seem to be correlated with LVH especially with concentric hypertrophy of the left ventricle in patients with essential hypertension.

Aged↗
PubMed2003

Ventricular function abnormalities in active rheumatoid arthritis: a Doppler echocardiographic study.

OBJECTIVE: The aim of the present study was to evaluate cardiac involvement in patients with active rheumatoid arthritis (RA). METHODS: Forty patients with active RA participated. All were submitted to standard Doppler echocardiography and myocardial performance index (MPI) grading. RESULTS: There were left and right ventricular diastolic function abnormalities in RA patients. Left ventricular MPI was also significantly higher than in controls ( P<0.05). A relationship was found between left ventricular early diastolic (E)/atrial (A) flow velocities (E/A ratio), isovolumic relaxation time (IRT), and disease duration ( r=-0.47 and P=0.002, r=0.618 and P=0.000, respectively). CONCLUSION: Diastolic function was impaired in both ventricles in patients with active RA. There was a direct relationship between some of the parameters of left ventricular diastolic function and disease duration as well. These findings suggest a subclinical myocardial involvement in RA patients.

Arthritis, Rheumatoid↗
PubMed2002

Analysis of the myocardial velocities in patients with mitral stenosis.

BACKGROUND: Pure mitral stenosis (MS) affects left-ventricular performance as a result of myocardial and functional factors. We planned this study to evaluate the effect of MS on right- and left-ventricular functions using Doppler tissue imaging (DTI). METHODS: A total of 46 patients with an established diagnosis of MS (mean age: 41 +/- 11 years), and 40 age-matched healthy individuals (mean age: 40 +/- 9 years) were included in this study. Echocardiography equipped with DTI function was performed on each participant. The mitral valve area was measured. Myocardial velocities were recorded at 4 different sites (septum, lateral, anterior, and inferior) of the left ventricle, and the right-ventricular free wall annulus by DTI. The positive systolic velocity when the mitral and tricuspid ring moved toward the cardiac apex, and 2 negative diastolic velocities when the mitral annulus moved toward the base away from the apex (1 during the early phase of diastole and another in the late phase of diastole [A(m)]) were measured. The early diastolic velocity/A(m) ratio was calculated for each wall. The mean of systolic and diastolic myocardial velocities of the left ventricle was calculated. Patients with pure MS were compared with healthy participants, and the relationship of DTI variables with mitral valve area was evaluated. RESULTS: The myocardial velocities of the left ventricle indicating left-ventricular function were found to be significantly lower in patients with pure MS. Right-ventricular annulus velocities, on the other hand, were similar in both groups. A significant positive correlation could be established between mitral valve area and mean positive systolic velocity, A(m) of the left ventricle, and right-ventricular A(m) (r = 0.50, P <.001; r = 0.48, P =.001; r = 0.45, P =.002, respectively), whereas a significant negative correlation (r = -0.42, P =.004) was established for right-ventricular early diastolic velocity/A(m) ratio. CONCLUSION: This first study where pure MS was evaluated by DTI shows that MS affects left-ventricular performance on long axis. The results indicate that the decrease in left-ventricular performance is caused by both functional and myocardial factors.

Adult↗
PubMed2002

[Do mobile telephones have adverse effects on the functions of implantable cardioverter defibrillators?].

OBJECTIVE: The aim of this study was to investigate the effects of widely used mobile telephones on the functions of implantable cardioverter-defibrillators (ICD). METHODS: The study included 9 patients (2 women, 7 men, mean age 65.5 +/- 6) with coronary artery disease who had underwent transvenous ICD implantation due to sustained ventricular tachycardia and/or fibrillation. First the test was performed on the basal conditions of ICD. Then, spontaneous heart rate of the patient was programmed to 10 beats/minute on VVI mode and the test was repeated. Two mobile telephones were located symmetrically 50 cm, 30 cm, 20 cm and 10 cm away from the ICD pocket in the pectoralis muscle and finally the mobile telephones antennas were touched to the pockets. On these different distances, the test was repeated during opening, standby, calling, talking and closing of the telephones. Possible ICD dysfunctions such as improper antitachycardic shock, inhibition of pacemaker functions, conversion to ventricular asynchronous mode (VOO) and development of ventricular trigger in devices with two chamber pacemaker functions were tested. The changes were observed on intracardiac and surface ECG's. RESULTS: There were no changes in the basal and pacemaker functions of ICD's and no symptoms in any patients. CONCLUSION: We have concluded that mobile telephones have no adverse effects on the functions of types of ICD assessed in the study.

Aged↗
PubMed2002

[Left ventricular hypertrophy increases the frequency of ventricular arrhythmia in hypertensive patients].

OBJECTIVE: To evaluate the relationship between left ventricular hypertrophy (LVH) and geometrical structure of the left ventricle with the risk of arrhythmia and QT dispersion (QTd) in hypertensive patients. METHODS: Eighty patients were included (mean age 53 +/- 11 years, 45 women) in the study. Among them, concentric LVH was present in 30, concentric remodelling in 15 and normal left ventricular geometry in 35 patients. Twenty-four hours electrocardiographic monitoring and QTd calculation were performed for all patients. RESULTS: Lown grade 2-3 ventricular arrhythmia was found in 30 patients (37%) and Lown grade 4a-4b ventricular arrhythmia was documented in 17 patients (21%). The frequency of >Lown 2 ventricular arrhythmia in patients with concentric LVH was significantly higher than those of the subjects with concentric remodelling or normal geometry (p<0.01). The percentage of >Lown 2 ventricular arrhythmias were 80% in patients with LVH and 10% in patients without LVH. QT and QTc dispersions in patients with concentric hypertrophy were significantly longer than those of the patients with concentric remodelling and normal geometry. Additionally, QT and QTc dispersions in patients with ventricular arrhythmias were more frequent than in those without (p<0.001). The left ventricular mass index correlated positively both with the QTd and the QTc dispersions (r=0.33, p=0.007, r=0.26, p= 0.03, respectively). The left ventricular mass index also correlated significantly with both grades (Lown 2-3 and Lown 4a-4b) of ventricular arrhythmia (r=0.59, p=0.001; r=0.53, p=0.001, respectively). CONCLUSION: In hypertensive patients, especially in those with concentric LVH, the incidence of ventricular arrhythmia increases in relation with QT dispersion.

Arrhythmias, Cardiac↗
PubMedDate not supplied

Can P wave parameters obtained from 12-lead surface electrocardiogram be a predictor for atrial fibrillation in patients who have structural heart disease?

This study was planned to investigate the parameters detecting risk of developing atrial fibrillation (AF) in patients with sinus rhythm with structural heart disease. Forty-five patients with AF and 37 patients without AF but with structural heart disease (Group I) were included in this study. Thirty-eight patients (Group II) had successfully undergone medically or electrically cardioversion after transesophageal echocardiography. The restoration of sinus rhythm could not be achieved in 7 patients who were excluded from this study. After providing sinus rhythm, amiodarone was given orally to the patients to prevent recurrences. Left ventricular ejection fraction (LVEF) was calculated and left atrial diameter (LAD) was measured by echocardiography in group I and in group II after cardioversion. A 12-lead electrocardiography (ECG) was simultaneously obtained from all the patients. In these ECG recordings, maximum P wave duration (P max), minimum P wave duration (P min), and P wave dispersion (P dispersion) were calculated. P dispersion was expressed as "P max-P min." Also, the highest P wave voltage is expressed as P amplitude maximum (P amp max), the lowest P wave as P amplitude minimum (P amp min), and P amplitude dispersion (P amp dispersion) was calculated as the difference of both. In univariate analysis, P max, P dispersion, P amp max, P amp dispersion, LAD, LVEF, and old age were significant predictors of chronic AF (p < 0.001, p < 0.01, p < 0.01, p < 0.01, p = 0.003, p = 0.02, and p = 0.01, respectively). However, in multivariate analysis, P max and LAD were independent predictors of chronic AF in patients with structural heart disease (r = 0.39, p < 0.05; r = 0.34; p < 0.05, respectively). In conclusion, in estimating the risk of developing chronic AF, P max and LAD are predictive parameters in patients with sinus rhythm with structural heart disease.

Atrial Fibrillation↗