The American journal of cardiology
-
Tocainide and quinidine were administered both as single agents and in combination to 14 patients with chronic ventricular arrhythmias. Therapy with tocainide was limited by the occurrence of dose-related adverse reactions in 8 patients, but could be titrated to a dose that was well-tolerated in 13 of 14 and effective in 2 of 13. ⋯ Analysis of electrocardiogram intervals showed that the drugs had additive effects on the coupling interval of the sinus beat to the predominant ectopic beat, but exerted antagonistic effects on the corrected QT interval. These findings suggest that the combination may be clinically useful, exerting pharmacologic effects unlike either agent alone.
-
This study determined whether noninvasive electrical impedance cardiography accurately measures systemic blood flow (cardiac output) in children with congenital heart defects. A total of 37 patients ranging in age from 2 to 171 months underwent complete right- and left-sided heart catheterizations that included simultaneous Fick and impedance measurement of cardiac output. Based on the diagnosis, 4 groups were formed consisting of a control group (n = 11) with no shunts, a group with intracardiac left-to-right shunting and an atrial septal defect (n = 7), another with a ventricular septal defect (n = 12) and an extracardiac left-to-right shunting with patent ductus arteriosus group (n = 7). ⋯ Fick pulmonary blood flow was significantly greater than impedance or Fick systemic flow in all 3 shunt groups. Impedance cardiography accurately measured systemic blood flow in children without shunts or valvular insufficiency. Likewise, systemic blood flow was accurately measured by impedance in the presence of intracardiac left-to-right shunts (atrial and ventricular septal defects) and extracardiac left-to-right shunts (patent ductus arteriosus).(ABSTRACT TRUNCATED AT 250 WORDS)
-
Randomized Controlled Trial Clinical Trial
Influence of long-term metoprolol treatment on early and late exercise test performance after acute myocardial infarction.
The effect of therapy on exercise performance during a 3-year follow-up after acute myocardial infarction (AMI) was evaluated in a double-blind randomized comparison between 154 patients given metoprolol (100 mg twice daily) and 147 patients given placebo. Exercise tests were performed 1.5, 6, 12, 24 and 36 months after AMI. Maximal accomplished workloads were similar in the 2 groups throughout follow-up. ⋯ Exercise-induced ventricular arrhythmias were significantly more common in the placebo group during the initial 6 months. Death, another AMI or both were significantly reduced by metoprolol treatment in patients with exercise-induced ST depression greater than or equal to 1 mm at the 6-week test. In a multiple logistic regression analysis maximal accomplished workload at 6 weeks (p less than 0.026), male sex (relative risk [rr] = 3.57, p = 0.016), previous AMI (rr = 3.07, p = 0.001), therapy with placebo (rr = 2.14, p = 0.007) and left ventricular failure (rr = 2.04, p = 0.023) were shown to carry independent prognostic information as well as exercise-induced ST-depression (greater than or equal to 1 mm) in placebo-treated patients (rr = 2.70, p = 0.01).