Association of heart rate profile during exercise with the severity of coronary artery disease.

BACKGROUND: Coronary artery disease is the leading cause of morbidity and mortality around the world. Autonomic nervous system abnormalities are associated with coronary artery disease and its complications. Exercise stress tests are routinely used for the detection of the presence of coronary artery disease. In this study, we observed the association between heart rate profile during exercise and the severity of coronary artery disease. METHOD AND RESULTS: One hundred and sixty patients with abnormal exercise treadmill test (> or =1 mm horizontal or downsloping ST-segment depression; 119 men, 41 women; mean age = 57 +/- 9 years) were included in the study. Use of any drug affecting heart rate was not permitted. Resting heart rate before exercise, maximum heart rate during exercise, and resting heart rate after exercise (5 min later) were measured and two parameters were calculated: heart rate increment (maximum heart rate - resting heart rate before exercise) and heart rate decrement (maximum heart rate - resting heart rate after exercise). All patients underwent selective coronary angiography and subclassified into two groups according to stenotic lesion severity. Group 1 had at least 50% of stenotic lesion and group 2 had less than 50%. Patients in the first group had increased resting heart rate, decreased maximum heart rate, decreased heart rate increment, and decreased heart rate decrement compared with second group. All patients were classified into tertiles of resting heart rate, heart rate increment, and heart rate decrement level to evaluate whether these parameters were associated with severity of coronary artery stenosis in the study. The multiple-adjusted odds ratio of the risk of severe coronary atherosclerosis was 21.888 (95% confidence interval 6.983-68.606) for the highest tertile of resting heart rate level compared with the lowest tertile. In addition, the multiple-adjusted odds ratio of the risk of severe coronary atherosclerosis was 20.987 (95% confidence interval 6.635-66.387) for the lowest tertile of heart rate increment level compared with the highest tertile and 2.360 (95% confidence interval 1.004-5.544) for the lowest tertile of heart rate decrement level compared with the highest tertile. CONCLUSION: Altered autonomic nervous system regulation affects heart rate profile, increased resting heart rate, decreased heart rate increment, and decreased heart rate decrement, during exercise and this effect is strongly and independently associated with the severity of coronary artery disease.

Coronary artery to left ventricular fistula demonstrated by transthoracic echocardiography.

Coronary artery fistulas are rare coronary anomalies which generally require coronary angiography for definitive diagnosis. Improvements in ultrasound technology has enabled direct, transthoracic visualization of long portions of coronary arteries. We report a patient with a symptomatic coronary to left ventricular fistula, which was diagnosed with transthoracic echocardiography.

Myocardial bridging as a cause of acute anterior myocardial infarction.

Myocardial bridging is systolic compression of an epicardial coronary arterial segment by overlying myocardium. It is a rare coronary anomaly, which is generally considered to be benign. It has been suggested that myocardial ischaemia may be seen. In this article, a case of myocardial infarction caused by myocardial bridging is presented.

Mean platelet volume in the patients with cardiac syndrome X.

BACKGROUND: Angina with normal coronary arteries, cardiac syndrome X, is a diagnosis of exclusion. The exact mechanism of this clinical syndrome remains unclear. Although the prognosis is as good as equal to that of normal population, symptoms related with the syndrome impair largely quality of life. Mean platelet volume showing the platelet size is an indicator of platelet function. Larger platelets are more active than smaller ones. METHODS AND RESULTS: We designed a study, evaluated mean platelet volume of the patients with cardiac syndrome X (group A) and stable angina (group B) and investigated the relation between groups. Eighty patients with cardiac syndrome X with a mean age of 51.08 +/- 9.79 years and 67 patients with stable angina with a mean age of 55.16 +/- 11.96 years were studied. At the end of the study, mean platelet volume of group A was significantly higher than that of group B, 10.55 +/- 1.08 fl vs. 9.39 +/- 0.58 fl, respectively (P < 0.001). CONCLUSION: Raised platelet size has been shown to be associated with adverse cardiac events. Mean platelet volume has increased in acute coronary syndromes and also in cardiac syndrome X in our study. Life style modification may optimize platelet size and improve symptoms in these patients.

[Do mobile telephones have adverse effects on the functions of implantable cardioverter defibrillators?]. / Mobil telefonlarin implante edilebilen kardiyoverter-defibrilatör fonksiyonlari uzerinde olumsuz etkileri olabilir mi?

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.