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Biomedical subjects

A Keren

Publications and source records attributed to A Keren.

At least 37 records · Page 2Linked to original sources
PubMed1996

Comparison between metoprolol orally osmotic once daily and metoprolol two or three times daily in suppressing exercise-induced and daily myocardial ischemia.

Metoprolol is a widely used anti-ischemic drug with a relatively short half-life. To improve patient' compliance and to provide 24-hour coverage, its once daily ORally OSmotic (OROS) formulation was developed. In this multicenter double-blind study, the anti-ischemic effects of metoprolol OROS given once daily at doses of 190 and 285 mg were compared to the regular metoprolol formulation of 100 mg 2 or 3 times daily. Sixty-five patients with stable coronary artery disease, positive exercise tests, and ischemic episodes during daily activity as recorded by ambulatory electrocardiographic monitoring (AEM) were included. In the OROS group, 23 patients completed all 3 treatment periods. In these patients, the number of myocardial ischemic episodes decreased from 239 on placebo to 128 during the 190 mg/day dose (p < 0.0001) and to 86 during the 285 mg/day treatment period (p < 0.0001). In the metoprolol group, there were 204 episodes at baseline and 142 and 140 during the 100 mg 2 or 3 times daily treatment periods (p < 0.0001 for both). During exercise testing, time to 1-mm ST depression increased significantly in the OROS group from 6.3 minutes at baseline to 7.1 and 9.6 minutes during 190- and 285-mg treatment periods. In the metoprolol group, it increased from 5.8 to 7.2 and 8.2 minutes, respectively. Both formulations of metoprolol were well tolerated. The OROS formulation was highly effective in suppressing daily and exercise-induced ischemia and exerted its effect throughout the 24-hour period.

Administration, Oral↗
PubMed1996

Effects of transdermal nicotine patches on ambulatory ECG monitoring findings: a double-blind study in healthy smokers.

The cardiovascular effects and safety of transdermal nicotine patches were assessed in 50 healthy smokers using repeated 48 hour ambulatory electrocardiographic monitoring as a part of a smoking cessation program. Following baseline measurements, subjects were randomized to active (n = 25) or placebo (n = 25) treatment groups for a period of 2 weeks. Twenty-two patients in each group completed the trial. During the treatment period, subjects also received behavioral supportive therapy. Heart rate and blood pressure were significantly reduced relative to baseline both groups. In the active treatment group, mean values at baseline and after 2 weeks of double-blind treatments were as follows: heart rates, 74.0 and 71.3 beats/min, respectively; systolic blood pressure, 108.9 and 106.9 mmHg; and diastolic blood pressure, 69.7 and 68.2 mmHg, respectively. Values for the placebo group were as follows: heart rate, 73.2 and 69.6 beats/min; systolic blood pressure, 110.6 and 105.3 mmHg; diastolic blood pressure, 71.4 and 70.5 mmHg. The confidence intervals of the mean for the differences between the groups are as follows: heart rate, -4.0 +8.2; systolic blood pressure, -6.7, +10.1; diastolic blood pressure, -7.9, +3.9. There were no changes in the frequency of atrial or ventricular arrhythmia as documented by repeated 48 hour ambulatory ECG recordings from baseline period before stopping smoking compared with the treatment period in the active as well as in the placebo groups. No ischemic events were detected in any of the volunteers during either the baseline or treatment periods. As a measure of smoking abstinence, we assessed the level of carbon monoxide in expired air; in the active group, the mean levels fell from 14.2 to 4.4 ppm after smoking cessation and in the placebo group from 13.2 to 4.2 ppm. The mean urine cotinine level fell from 8.18 mmol/l at baseline to 5.74 mmol/l after 2 weeks of treatment in the active group and from 8.78 to 3.93 mmol/l in the placebo group. The number of cigarettes smoked per week in both treatment groups was significantly reduced: from 175.2 to 8.4 for the active group and from 136 to 8.6 for the placebo group. Eleven out of 22 subjects in each group quit smoking completely. Smoking withdrawal symptoms during the first week of treatment were more severe in the placebo group than in those on active treatment. There were no significant side effects in either the placebo or the active treatment groups. These results indicate that nicotine delivered by transdermal system is free of cardiac adverse effects in healthy volunteers.

Administration, Cutaneous↗
PubMed1996

Accuracy of biplane and multiplane transesophageal echocardiography in diagnosis of typical acute aortic dissection and intramural hematoma.

OBJECTIVES: The purpose of this study was to evaluate the diagnostic accuracy of biplane and multiplane transesophageal echocardiography in patients with suspected aortic dissection, including intramural hematoma. BACKGROUND: Transesophageal echocardiography is a useful technique for rapid bedside evaluation of patients with suspected acute aortic dissection. The sensitivity of transesophageal echocardiography is high, but the diagnostic accuracy of biplane and multiplane transesophageal echocardiography for dissection and intramural hematoma is less well defined. METHODS: We studied 112 consecutive patients at a major referral center who had undergone biplane or multiplane transesophageal echocardiography to identify aortic dissection. The presence, absence and type of aortic dissection (type A or B, typical dissection or intramural hematoma) were confirmed by operation or autopsy in 60 patients and by other imaging techniques in all. The accuracy of transesophageal echocardiography for ancillary findings of aortic dissection (intimal flap, fenestration and thrombosis) was assessed in the 60 patients with available surgical data. RESULTS: Of the 112 patients, aortic dissection was present in 49 (44%); 10 of these had intramural hematoma (5 with and 5 without involvement of the ascending aorta). Of the remaining 63 patients without dissection, 33 (29%) had aortic aneurysm and 30 (27%) had neither dissection nor aneurysm. The overall sensitivity and specificity of transesophageal echocardiography for the presence of dissection were 98% and 95%, respectively. The specificity for type A and type B dissection was 97% and 99%, respectively. The sensitivity and specificity for intramural hematoma was 90% and 99%, respectively. The accuracy of transesophageal echocardiography for diagnosis of acute significant aortic regurgitation and pericardial tamponade was 100%. CONCLUSIONS: Biplane and multiplane transesophageal echocardiography are highly accurate for prospective identification of the presence and site of aortic dissection, its ancillary findings and major complications in a large series of patients with varied aortic pathology. Intramural hematoma carries a high complication rate and should be treated identically with aortic dissection.

Acute Disease↗
PubMed1995

Atrial septal aneurysm in adult patients. A multicenter study using transthoracic and transesophageal echocardiography.

BACKGROUND: An atrial septal aneurysm (ASA) is a well-recognized abnormality of uncertain clinical relevance. We reevaluated the clinical significance of ASA in a large series of patients. The aims of the study were to define morphological characteristics of ASA by transesophageal echocardiography (TEE), to define the incidence of ASA-associated abnormalities, and to investigate whether certain morphological characteristics of ASA are different in patients with and without previous events compatible with cardiogenic embolism. METHODS AND RESULTS: Patients with ASA were enrolled from 11 centers between May 1989 and October 1993. All patients had to undergo transthoracic and transesophageal echocardiography within 24 hours of each other; ASA was defined as a protrusion of the aneurysm > 10 mm beyond the plane of the atrial septum as measured by TEE. Patients with mitral stenosis or prosthesis or after cardiothoracic surgery involving the atrial septum were excluded. Based on these criteria, 195 patients 54.6 +/- 16.0 years old (mean +/- SD) were included in this study. Whereas TEE could visualize the region of the atrial septum and therefore diagnose ASA in all patients, ASA defined by TEE was missed by transthoracic echocardiography in 92 patients (47%). As judged from TEE, ASA involved the entire septum in 100 patients (51%) and was limited to the fossa ovalis in 95 (49%). ASA was an isolated structural defect in 62 patients (32%). In 106 patients (54%), ASA was associated with interatrial shunting (atrial septal defect, n = 38; patent foramen ovale, n = 65; sinus venosus defect, n = 3). In only 2 patients (1%), thrombi attached to the region of the ASA were noted. Prior clinical events compatible with cardiogenic embolism were associated with 87 patients (44%) with ASA; in 21 patients (24%) with prior presumed cardiogenic embolism, no other potential cardiac sources of embolism were present. Length of ASA, extent of bulging, and incidence of spontaneous oscillations were similar in patients with and without previous cardiogenic embolism; however, associated abnormalities such as atrial shunts were significantly more frequent in patients with possible embolism. CONCLUSIONS: As shown previously, TEE is superior to the transthoracic approach in the diagnosis of ASA. The most common abnormalities associated with ASA are interatrial shunts, in particular patent foramen ovale. In this retrospective study, patients with ASA (especially with shunts) showed a high frequency of previous clinical events compatible with cardiogenic embolism; in a significant subgroup of patients, ASA appears to be the only source of embolism, as judged by TEE. Our data are consistent with the view that ASA is a risk factor for cardiogenic embolism, but thrombi attached to ASA as detected by TEE are apparently rare.

Case-Control Studies↗
PubMed1994

Correlation of exercise-induced ST depression in precordial electrocardiographic leads after inferior wall acute myocardial infarction with thallium-201 stress scintigraphy, coronary angiography and two-dimensional echocardiography.

Fifty-eight of 220 consecutive patients had exercise-induced ST depression in some or all precordial leads 3 to 12 months after a first inferior myocardial infarction. All 58 patients underwent thallium-201 exercise testing, 2-dimensional echocardiography and coronary angiography. ST depression was confined to leads V1-4 in 22 patients (group A); thallium-201 exercise testing showed reversible anterior perfusion defects and left anterior descending coronary artery disease in 11 of the 22 patients (50%). None of the other 11 with negative thallium-201 exercise test results had significant left anterior descending narrowing, and the anterior ST depression could be explained by asynergy of the posterior wall found on 2-dimensional echocardiography in 10. ST depression appeared in leads V5-6 in 22 patients (group B); reversible anterior perfusion defects and left anterior descending disease was demonstrated in 18 patients (82%). In the other 4 patients posterior wall asynergy was demonstrated. ST depression was seen from leads V1-6 in 14 patients (group C); reversible anterior perfusion defects were seen in 6 patients (43%), 5 of whom had significant left anterior descending disease. Among the other 8 patients without reversible anterior perfusion defects, posterior wall asynergy was found in 6.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Aborted sudden death in a young patient with isolated granulomatous myocarditis.

A young athlete was successfully resuscitated from ventricular fibrillation. Subsequently severe heart failure developed and endomyocardial biopsy showed granulomatous myocarditis. Following steroid therapy, repeated biopsies demonstrated partial resolution of the inflammatory changes and mild myocardial fibrosis; the granulomas disappeared, and the patient recovered both clinically and haemodynamically. Three years later, the patient is asymptomatic, is practising long distance jogging, has a normal left ventricular ejection fraction and no evidence of arrhythmias.

Adult↗