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Biomedical subjects

K Bargheer

Publications and source records attributed to K Bargheer.

7 recordsLinked to original sources

Long-term prognosis of patients with anginalike chest pain and normal coronary angiographic findings.

OBJECTIVES: This study analyzes the long-term course of patients with typical angina pectoris or anginalike chest pain and normal coronary angiographic findings. BACKGROUND: In previous studies of such patients the rate of occurrence of typical coronary events during follow-up has differed widely, depending on the duration of the study and the number of patients. METHODS: One hundred seventy-six patients (mean age 48.3 years) who underwent coronary and left ventricular angiography for typical angina or anginalike chest pain were followed up for 5.8 to 15.8 years (median 12.4). By definition, all patients had normal findings on coronary and left ventricular angiograms; exercise test results were positive in 31. RESULTS: Fourteen patients (8%) had a coronary event (0.65%/year) after an average of 9.3 years (median 9.2). Two of the 14 died of a coronary event (0.09%/year), 1 of cardiogenic shock during acute myocardial infarction, 1 suddenly; 4 had a nonfatal myocardial infarction at an average of 8.1 years (median 9.1); 8 had severe angina pectoris after an average of 10.3 years (median 11.1), confirmed by a second angiogram, now with positive findings. Two patients died of a noncoronary cardiac event (chronic cor pulmonale due to obstructive lung disease, acute pulmonary embolism), eight of a noncardiac cause, mainly cancer. None of the 31 patients with a positive exercise test result had a coronary event. Patients with a coronary event had significantly more risk factors (hypercholesterolemia, hypertension, cigarette smoking, diabetes type II) than did those without an event (average 2.4/patient vs. 1.3/patient, p < 0.01). Chest pain persisted in 133 (81%) of the 164 survivors and disappeared in 31 (19%). CONCLUSIONS: Patients with typical angina or anginalike chest pain and normal coronary angiograms have a good long-term prognosis despite persistence of pain for many years; coronary morbidity and mortality are similar to those of the overall population. An increased risk for the development of coronary events is present mainly in patients with elevated risk factors.

Angina Pectoris↗

Prolongation of monophasic action potential duration and the refractory period in the human heart by tedisamil, a new potassium-blocking agent.

The effect of intravenous tedisamil (0.3 mg.kg-1), a newly developed potassium-blocking agent, on ventricular repolarization was studied in 10 patients (three women, seven men; mean age 53 +/- 8 years) with coronary artery disease (stenoses < or = 60%). Left ventricular monophasic action potentials, effective refractory periods and surface electrocardiograms were recorded during sinus rhythm and during constant atrial pacing at cycle lengths of 600, 500 and 400 ms. Under tedisamil there was a 12% reduction of heart rate and in parallel a prolongation of QTc interval (+10%) and left ventricular monophasic action potential duration (+16% at 90% repolarization). QRS duration remained unchanged. Tedisamil increased the duration of monophasic action potentials during constant atrial pacing, indicating a direct prolongation effect on left ventricular repolarization independent of sinus node activity. By increasing the atrial pacing rate this prolonging effect diminished. Left ventricular effective refractory periods also increased in a frequency-dependent fashion with a greater prolongation effect at long cycle lengths as compared to short cycle lengths. The ratio between effective refractory period and monophasic action potential duration, however, remained constant, independent of heart rate. We conclude that tedisamil is bradycardiac at the dose tested and has a reverse use dependent prolongation effect on left ventricular repolarization and refractoriness. The electrophysiologic profile is consistent with a class III antiarrhythmic classification.

Action Potentials↗

[Long-term follow-up of patients with angina pectoris-like chest pain and normal coronary angiogram].

To determine the long-term prognosis of patients (pts) with angina-like chest pain and normal coronary arteriograms, 178 pts (61 women, 117 men; mean age 48.1 years) were followed for an average of 9.8 years (5.5-13.1 years). Eight pts (4.5%) died during follow-up: One pt from acute myocardial infarction, one pt suddenly, one pt from chronic cor pulmonale and 5 pts from non-cardiac diseases. Chest pain remained constant in 137/170 surviving pts (80.6%), but disappeared in 33 pts (19.4%). Nine of the 178 pts (5.1%) developed manifest coronary artery disease (CAD): four of them (2.2%) acute myocardial infarctions including one death, after an average of 7.2 years; in five pts (2.8%) with continued chest pain a second coronary angiogram showed typical CAD. These pts with manifest CAD averaged 2.1 risk factors: six pts were smokers, two pts had elevated cholesterol levels (> 7.5 mmol/l), three pts had elevated triglyceride levels (> 2.4 mmol/l), two pts had a diabetes mellitus type IIa and six pts were hypertensives. Patients without manifestation of CAD averaged only 1.4 risk factors (p < 0.05). Our data show that pts with angina-like chest pain and normal coronary angiograms have an excellent long-term prognosis (only 0.51% of patients with new manifestations of CAD per year). However, angina-like chest pain can persist over many years.

Adult↗

Monophasic action potential mapping in human subjects with normal electrocardiograms: direct evidence for the genesis of the T wave.

T wave concordance in the normal human electrocardiogram (ECG) generally is explained by assuming opposite directions of ventricular depolarization and repolarization; however, direct experimental evidence for this hypothesis is lacking. We used a contact electrode catheter to record monophasic action potentials (MAPs) from 54 left ventricular endocardial sites during cardiac catheterization (seven patients) and a new contact electrode probe to record MAPs from 23 epicardial sites during cardiac surgery (three patients). All patients had normal left ventricular function and ECGs with concordant T waves. MAP recordings during constant sinus rhythm or right atrial pacing were analyzed for activation time (AT) = earliest QRS deflection to MAP upstroke, action potential duration (APD) = MAP upstroke to 90% repolarization, and repolarization time (RT) = AT plus APD. AT and APD varied by 32 and 64 msec, respectively, over the left ventricular endocardium and by 55 and 73 msec, respectively, over the left ventricular epicardium. On a regional basis, the diaphragmatic and apicoseptal endocardium had the shortest AT and the longest APD, and the anteroapical and posterolateral endocardium had the longest AT and the shortest APD (p less than .05 to less than .0001). RT was less heterogeneous than APD, and no significant transventricular gradients of RT were found. In percent of the simultaneously recorded QT interval, epicardial RT ranged from 70.8 to 87.4 (mean 80.7 +/- 3.9) and endocardial RT ranged from 80 to 97.8 (mean 87.1 +/- 4.4) (p less than .001).(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗