Güneş Akgün

Analysis of high frequency QRS potentials observed during acute myocardial infarction

The value of high frequency QRS potentials (HFQRS) during acute myocardial infarction (AMI) was assessed to define infarct size and prognosis. HFQRS were recorded by signal-averaged ECG with 150-250 Hz frequency ranges, using X, Y, Z orthogonal leads. Recordings were obtained in surviving AMI patients (n = 33, 12 inferior, 11 anterior, 10 anterior-inferior) on the first and tenth days, but in non-survived patients (n = 5, 2 inferior, 1 anterior, 2 anterior-inferior) only on the first day. Additionally, the frequency of ventricular tachycardia (VT) was evaluated by 24-h Holter monitoring in all patients at the same days. The control group consisted of 11 healthy people. In surviving AMI patients, RMS voltage of vector magnitude reduced in anterior and anterior-inferior MI but filtered QRS duration was longer in inferior MI than normals (P < 0.05, < 0.05, < 0.01, respectively). In nonsurvived patients, RMS voltages of leads X, Y, Z and vector magnitude were lower than normals (P < 0.01, < 0.05, < 0.01, < 0.01, respectively) and surviving AMI patients (P < 0.01, < 0.05, < 0.05, < 0.05, respectively), the filtered QRS duration was found to be longer than normals and survived patients (P < 0.01, < 0.01). In patients who had VT on Holter monitoring, filtered QRS duration was significantly longer than in patients without VT (P < 0.05). As a result, HFQRS was important for defining infarct size but not malignant ventricular arrhythmias. VT was related to filtered QRS duration. HFQRS may offer significant prognostic information and contribute to early risk stratification of AMI patients.

Is sublingual nifedipine administration superior to oral administration in the active treatment of hypertension

Nifedipine, a calcium-channel-blocking agent, was administered orally to 44 untreated patients (Group A) and sublingually to 51 untreated patients (Group B) who had a diastolic blood pressure more than 90 mm Hg and systolic blood pressure more than 140 mm Hg. The mean pretreatment systolic and diastolic blood pressure values were 185.3 ± 26.0 and 115.1 ± 13.4 mm Hg in Group A patients and 193.6 ± 23.1 and 118.1 ± 14.1 mm Hg in Group B patients respectively (p >0.05). The hypotensive activity of nifedipine was observed at the tenth minute in both groups. Mean systolic and diastolic pressures were 168.9 ± 23.7 and 101.9 ± 14.2 mm Hg in Group A and 170.6 ± 26.2 and 103.0 ± 15.8 mm Hg in Group B, (p < 0.001) Diastolic blood pressures dropped under 100 mm Hg at the twentieth minute in both groups. Maximal reduction of blood pressure was observed at the fortieth minute in both groups and the degree of reduction in blood pressure was also the same (mean systolic and diastolic blood pressures: 143.7 ± 22.1 and 86.9 ± 11.7 in Group A and 148.7 ± 21.4 and 91.7 ± 17.0 in Group B (p >0.05) The authors conclude that sublingual nifedipine administration is not supe rior to oral nifedipine administration (in capsular form) in the acute treatment of hypertension.

Intravascular volume dependency of left ventricular mass calculation by two-dimensional guided M-mode echocardiography

BACKGROUND Increased left ventricular mass (LVM) is an independent risk factor for cardiovascular morbidity and mortality, and may be used for risk stratification. Two-dimensional echocardiography, the most commonly used technique for estimation of LVM, uses the third power of the left ventricular internal diameter (LVID) for the calculation. OBJECTIVES To determine whether a decrease in intravascular volume after dialysis may cause inaccurate estimation of LVM by echocardiography. METHODS Thirty-eight patients undergoing hemodialysis due to chronic renal failure constituted the study group (14 women [37%] and 24 men [63%], mean age +/- SD 38.7+/-10.9 years). LVID, and interventricular and posterior wall thicknesses were measured by two-dimensionally guided M-mode echocardiography. Stroke volume and cardiac output were calculated using left ventricular outflow tract diameter and the pulsed-wave Doppler time-velocity integral obtained from left ventricular outflow tract. LVM was calculated by using Devereuxs formula, and was indexed for body surface area and height. All echocardiographic parameters were measured or calculated before and after dialysis (on the same day), and then compared. RESULTS There were no significant changes in wall thickness; however, LVID, LVM, the LVM/body surface index and the LVM/height index significantly decreased after dialysis (P<0.001 for each parameter). There was a significant correlation between the change in LVID and the change in LVM (P<0.001, r=0.59). Stroke volume and cardiac output also decreased significantly after hemodialysis (P<0.001 for each parameter). CONCLUSIONS Intravascular volume-dependent change in LVID causes inaccurate estimation of LVM, so volume status should be kept in mind, especially in serial assessment of LVM.

Exercise performance in patients with dilated cardiomyopathy: relationship to resting left ventricular function

Relationship between maximal exercise tolerance and resting indexes of left ventricular systolic and diastolic function were evaluated in 35 men, aged 55.1 +/- 10.4 years, with dilated cardiomyopathy. Clinical diagnosis of dilated cardiomyopathy was confirmed with M-mode echocardiography (M-mode echocardiographic end-diastolic dimension >55 mm, fractional shortening <25%, increased E point septal separation). Coronary angiography was considered mandatory for exclusion of patients with coronary artery disease. Patients with mitral regurgitation (> or =grade 2) and rhythm other than sinus were excluded. According to the functional classification of New York Heart Association 6 patients were in class I, 11 in class II, 12 in class III and 6 in class IV. Left ventricular ejection fraction (LVEF), stroke volume (SV) and left ventricular end-diastolic pressure (LVEDP) were measured with contrast angiography. Peak early (VE) and late (VA) transmitral filling velocities and their ratio (E/A), isovolumetric relaxation time (IRT) and deceleration time (DT) were computed from pulsed wave Doppler echocardiograms. On completion of all resting measurements, patients underwent symptom limited upright treadmill exercise testing using a modified Naughton protocol and maximal exercise performance metabolic equivalent work load (NETS) was calculated from the speed, incline and length of time at the stage using standard tables to make interpatient comparisons. Significant correlation has been found between NYHA class and METS (r= -0.77, P<0.001). However NYHA class II and NYHA class III patients were found to have similar METS (P=0.317). Patients were further divided into two groups on the basis of exercise data. Group I consisted of 22 patients with relatively preserved exercise tolerance (> or =4 METS) and Group II included 13 patients with impaired exercise tolerance (> or =4 METS). This arbitrary classification was based upon previously described survival differences in these two groups. There were no differences between two groups in terms of age, gender distribution (all were male), heart rate and arterial blood pressure. LVEF, LVEDP, stroke volume, VE, VA, E/A, IRT and DT were also similar between two groups. Strong positive correlation was observed between LVEDP and VE (r=0.74) while IRT and VA negatively correlated with LVEDP (r= -0.77 and r= -0.81 respectively) but neither of resting indexes of left ventricular systolic and diastolic function showed significant correlation with METS and exercise duration.

Effects of Percutaneous Transluminal Coronary Angioplasty on Late Potentials and High Frequency Mid-QRS Potentials

The high frequency mid-QRS potentials and late potentials are important in coronary artery disease because they are related to the extent of ischemia and prognosis. In this study, the effects of successful percutaneous transluminal coronary angioplasty (PTCA) on these potentials were evaluated. Twenty-four patients with coronary artery disease (aged 34-67 years, 5 women, 19 men) were examined. Eight of these patients had a history of myocardial infarction (4 anterior, 3 inferior, 1 anterior and inferior). Signal averaged ECG was recorded at 40- to 250-Hz frequency ranges for late potentials and 150- to 250-Hz frequency ranges for mid-QRS potentials before PTCA, and they were repeated 1 month later. The QRS duration (107.7 +/- 9.8 to 105.3 +/- 9.3 ms, p < 0.0001) root-mean-square voltage (39.4 +/- 20.1 to 47.7 +/- 22.2 microV, p < 0.00001) and low amplitude signal duration (30.7 +/- 9.9 to 27.7 +/- 9.3 ms, p < 0.001) showed significant changes in 40- to 250-Hz ranges before and after PTCA. The same results were also obtained in the 150- to 250-Hz frequency ranges: the QRS duration decreased (90.9 +/- 9.8 to 86.5 +/- 9.1 ms, p < 0.005) and the root-mean-square voltage increased (5.5 +/- 1.6 to 6.1 +/- 1.8 microV, p < 0.00001). Thus, successful PTCA causes improvement in late potential parameters, so the risk of malign arrhythmia that affects the prognosis can be reduced. Additionally, the increase in high frequency mid-QRS potentials shows the decrease in the ischemia after PTCA.

Rate-dependent ST segment depression--a case report.

A patient with resting heart rate over 100 beats per minute (bpm) displayed 1.5-2 mm ST segment depression in her ECG during daily activities. She had unprovoked further increase in her heart rate up to 145 bpm, and during these episodes, her ECG displayed further ST segment depression up to 3 mm and of 0.12 second duration. An organic cause could not be found to explain her sinus tachycardia. Results of all laboratory investigations, including coronary angiography, were normal. It was observed that during an episode of reflex vagotonia, when her heart rate was below 95 bpm, her previously depressed ST segments became isoelec tric. With the thought that this patients ST segment depression was rate depen dent, carotid sinus massage was performed, and when the heart rate slowed to 95 bpm her depressed ST segments became isoelectric. The same response was accomplished with beta blockers. Sympathetic hyperactivity was thought to be the most likely mechanism of ST segment depression in this patient. A critical increase in heart rate caused these ECG abnormalities.

Düşük doz pravastatin tedavisinin fibrinojen, C–reaktif proteni, C3 kompleman düzeylerine etkisi

Aim : To investigate the effect of low dose pravastatin on C-Reactive-Protein (CRP), fibrinogen, and C3 complement levels in patients with hypercholestremia.Method: Fifty-seven patients with hypercholestremia formed the study patients. Patients were divided into two groups. Group 1 (the study group) consisted of 37 patients (19 of them had hypercholestremia and hypertension, 5 had previous myocardial infarction, 13had hypercholestremia). Mean age was 54.3 and mean cholesterol was 266 mg/dl. CRP levels were measuredwith nepholemetric method and fibrinogen levels weremeasured with Clauss method. Those patients were initiated 10 mg pravastatin daily on top of a AmericanHeart Association Step 1 diet therapy and CRP, fibrinogen and C3 levels were remeasured 2 months later. Group 2 (the control group) consisted of 20 patients (13 had hypertension and hypercholestremia, 7 had hypercholestremia). Mean age was 56.3 and mean cholesterol was 239 mg/dl. Group 2 had a American Heart Association Step 1 diet therapy and they had their CRP, Fibrinogen, and C3 levels measured at the beginning of diet therapy and and two months later.Results: Group 1 had their fibrinogen and CRP levels lowered statistically significantly (p