American heart journal
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American heart journal · Aug 1987
Failure of episodic high-dose oral verapamil therapy to convert supraventricular tachycardia: a study of plasma verapamil levels and gastric motility.
The practicality of administering large oral doses of verapamil tablets to terminate supraventricular tachycardia (SVT) was investigated in 10 patients. A pilot study in four patients showed that unexpectedly low plasma levels (less than 40 ng/ml) were obtained 60 minutes after administering 160 mg or 240 mg of verapamil during SVT. Nuclear studies in the six other patients showed that fractional liquid gastric emptying times (T) were significantly prolonged in SVT compared to sinus rhythm (SR), p less than 0.05 from T 1/3 onward. ⋯ SVT was terminated by verapamil in one patient after 40 minutes and the rate of SVT was slowed after 90 minutes in two other patients. Thus plasma verapamil levels are considerably reduced during SVT as compared to SR, and changes in gastric emptying are likely a contributing cause. Since SVT was converted to sinus rhythm in only 1 of 10 patients within 1 hour, large oral doses of verapamil tablets appear unsatisfactory for the episodic treatment of SVT.
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American heart journal · Aug 1987
Natural history of pulmonary hemodynamics in primary pulmonary hypertension.
To study the relationship between the hemodynamic characteristics and prognosis in PPH, we analyzed the data on patients whose prognosis was well documented from the time of hemodynamic monitoring. Our subjects were 87 patients obtained from a nationwide survey in Japan. PCWPs were obtained in 44 patients and COs were measured in 59 patients. ⋯ The partial pressure of oxygen of arterial blood was the only variable discriminating sudden deaths from right-sided heart failure deaths (54 +/- 2 vs 66 +/- 4 mm Hg; p less than 0.05). The results of this study indicate that the major determinant of prognosis is right ventricular function and that the CI might be used as a prognostic indicator. In addition, sudden death is more likely to occur in patients with severe hypoxia.
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American heart journal · Jul 1987
Comparative StudyVasodilators as first-line therapy for congestive heart failure: a comparative hemodynamic study of hydralazine, digoxin, and their combination.
Although digitalis and vasodilators both enhance cardiac performance in patients with congestive heart failure, their relative efficacy is unknown. Accordingly, the acute hemodynamic effects of intravenous hydralazine (0.15 mg/kg), digoxin (1.0 mg), and the hydralazine-digoxin combination were evaluated in 14 normotensive heart failure patients at sitting rest, nine of whom were also studied during submaximal upright bicycle exercise. Hemodynamic responses at rest and exercise were similar. ⋯ Thus, hydralazine is at least as effective as digoxin in improving cardiac function over the short term. Vasodilators may constitute an acceptable alternative to digitalis as initial therapy for congestive heart failure, except where a reduction in systemic arterial pressure is potentially deleterious. Use of combined treatment produces greater increases in cardiac output than with either drug alone, but requires risking the toxicities of two agents.