ISSN:0009-7322    

出版商:OVID    

年代:1985

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1985

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1985

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Sixty patients with a first acute myocardial infarction and no current treatment with cardioactive drugs were included in a prospective study of the relationship between serum potassium concentration and the early occurrence of ventricular tachycardia and premature ventricular contractions (PVCs). Serum potassium level (range 2.5 to 5 mmol/liter) was estimated 3.8 + 2.5 hr (mean + SD) after the onset of the infarction, and Holter monitoring was performed during the subsequent 12 hr. In multivariate analysis, serum potassium level was negatively and age positively related to ventricular tachycardia. Among the subclasses of PVCs (frequent unifocal, multifocal, couplets, bigeminy), serum potassium concentration was negatively related to the frequent unifocal subclass; hypertension was related to couplets and to the presence of any of the subclasses, and serum aspartate aminotransferase concentration was related to multifocal PVCs. Heart failure leading to death was related to all subclasses of PVC. Serum potassium concentration is an independent inverse predictor of the occurrence of ventricular tachycardia and frequent unifocal PVCs early in acute myocardial infarction.

ISSN:0009-7322    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Fifty-two patients with isolated congenital ventricular septal defects (VSDs), studied for the first time at age 10 or older, were restudied an average of 16 years later (range 4 to 2 1). The study protocol included a symptom-limited bicycle ergometer test. M mode echocardiographic examination, and hemodynamic studies at rest and during mild supine exercise. Of the 52, 17 had been operated on an average of 19 years earlier (range 1 1 to 21) (group 1) and 35 with smaller defects were not operated on (group 2). Although more pronounced findings were made in group 1, a similar pattern was observed in group 2: (1) In most subjects in both groups a subnormal working capacity was observed. (2) A subnormal left ventricular fractional shortening and circumferential shortening velocity was noted in a high proportion at echocardiography. (3) A number of hemodynamic aberrations were observed in a high proportion of patients during exercise but not at rest. Thus a subnormal increase in left and right ventricular cardiac output was found in addition to pathologic increase in right and left ventricular enddiastolic, pulmonary arterial, and pulmonary capillary wedge pressures. In group 1, elevated pulmonary arterial pressures before operation and/or small residual VSDs were associated with a poor hemodynamic outcome. In neither group could significant correlations be observed between hemodynamic aberrations, shunt size, and/or age. Among patients who underwent surgery, the earlier surgical trauma might have contributed to the functional aberrations, but in group 2 the only likely explanation for the findings seems to be the VSD itself. Possibly a long-standing VSD- found unnecessary to repair according to commonly accepted criteria may lead to disturbed systolic function and increase in compliance of both ventricles via a chronic pressure and volume overload.

ISSN:0009-7322    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Simultaneous determinations of cardiac output and brachial arterial blood flow were performed in patients with hypertension and high cardiac output in comparison with normal subjects of the same age. Brachial arterial blood flow was measured with a previously described pulsed Doppler apparatus that permitted the noninvasive determination of arterial diameter and blood flow velocity. In patients with borderline hypertension, brachial blood flow was significantly increased (136 + 1 1 vs 72 −+− 8 ml/min; p < .001). After short-term administration of indomethacin, cardiac output decreased while brachial blood flow remained constant. After short-term administration of a selective β1-receptor antagonist (primidolol) and nonselective blocker (propranolol), cardiac output decreased significantly in both cases but the decrease in brachial blood flow was significant only after the administration of the nonselective β-blocking agent. The study strongly suggested that in patients with borderline hypertension, the increased cardiac output is related to a prostaglandin and β1-adrenergic mechanisms whereas the increased brachial blood flow depends mainly on β2-adrenergic mechanisms.

ISSN:0009-7322    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

The prognostic significance of a preoperative echocardiographic left ventricular endsystolic dimension (ESD) greater than 55 mm and/or fractional shortening (FS) of 25% or less was evaluated retrospectively in 84 patients who had undergone aortic valve replacement for isolated chronic aortic regurgitation due to various causes. Postoperative survival, improvement in symptoms, and echocardiographic evidence of regression of left ventricular dilatation and hypertrophy were compared between patients with a preoperative ESD greater than 55 mm (category 1) and those with an ESD of 55 mm or less (category 2) and between patients with FS of 25% or less (category 3) and those with FS greater than 25% (category 4). Patients in categories 1 and 3 had a higher preoperative left ventricular end-diastolic dimension (EDD) and cross-sectional area than those in categories 2 and 4, respectively, but their preoperative functional impairment (NYHA class) was similar. There were 13 deaths, only two of which (one early, one late) could be attributed to left ventricular dysfunction. In both, FS was 25% or less and in one ESD was greater than 55 mm. There was a weak association without useful positive predictive value between the echocardiographic variables and postoperative death due to all causes. Among 42 patients with a preoperative ESD greater than 55 mm and/or FS of 25% or less, 33 (79%) were alive at a mean follow-up of 29.5 months. Symptoms improved in all categories of survivors, with the postoperative NYHA class being similar between categories 1 and 2 and between categories 3 and 4. Among 48 survivors with high-quality echocardiograms both before and after surgery, EDD fell in all groups but fell to a lesser extent in category 3 than in category 4. Postoperative cross-sectional area fell to the same level in all categories. Follow-up intervals were similar in all categories. We conclude that in patients undergoing aortic valve replacement for chronic aortic regurgitation, a preoperative ESD greater than 55 mm or an FS of 25% or less does not reliably predict early or late death, does not correlate with lack of improvement in symptoms, and does not preclude postoperative regression of left ventricular dilatation and hypertrophy. Thus these echocardiographic criteria alone cannot be used for the timing of surgical intervention in these patients.

ISSN:0009-7322    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

The functional significance of coronary collateral flow from a nonobstructed supply artery was studied in 121 patients with severe (>80%) single-vessel disease, 64 with and 57 without Q wave infarction. All patients underwent exercise thallium imaging and coronary angiography. On angiography, collateral flow was present in 85% of 74 occluded arteries compared with only 17% of 47 arteries with subtotal obstruction (p < .001). Collateral flow was not seen in arteries with lesions of less than 90% obstruction. Collateral flow was present in 100% of 29 occluded arteries in patients without Q wave infarction compared with only 76% of 45 occluded arteries with Q wave infarction (p < .005). Clinical variables did not correlate with collateral flow. Collateral flow did not prevent ischemia on exercise thallium imaging in patients without Q wave infarction: 30 of 33 (9 1%) with collateral flow had reversible thallium defects compared with 24 of 24 (100%) without collateral flow (p = NS). In patients with Q wave infarction, partially reversible exercise thallium defects (peri-infarctional ischemia) were more common with flow to the area from either subtotal obstruction (73%) or collateral flow (45%) than with no flow from total occlusion (27%; p = .05). In patients with severe single-vessel disease the presence of collateral flow is principally determined by coronary occlusion. Collateral flow may protect from Q wave infarction but does not prevent exercise ischemia on thallium imaging.

ISSN:0009-7322    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Adaptation to exercise or the “warm up phenomenon” has been observed in some patients with angina pectoris. To investigate adaptation, eleven patients with exertional angina pectoris and angiographic evidence of coronary artery disease underwent two identical bouts of sequential tachycardia stress separated by a brief recovery period. Manifestations of ischemia were less during the second stress, as evidenced by a reduction in the severity of angina pectoris, less ST segment depression, and improved lactate extraction. Peak coronary blood flow during the second stress (81 + 20 ml/min) was not significantly different from that during the first (95 + 32 ml/min). Regional myocardial oxygen consumption, however, was significantly (p = .03) lower during the second stress (8.8 2.4 ml 02/min) when compared with the first (1 1.4 + 3.0 ml 02/min). Thus, patients with coronary artery disease can develop anginal tolerance to the stress of tachycardia similar to that observed after repeated bouts of exercise. A relative reduction in myocardial oxygen consumption, rather than an increase in coronary blood flow, appears to account for this phenomenon.

ISSN:0009-7322    

出版商:OVID    

年代:1985

数据来源: OVID