Beta-adrenergic blocking drugs in the treatment of congestive heart failure

Experimental and clinical data suggests that increased serum catecholamines may have predominantly detrimental effects in patients with congestive heart failure. Some investigators have proposed use of beta-blockers in heart failure as a means of ameliorating the harmful effects of the excess catecholamines. The clinical experience to date with use of these agents as therapy in congestive heart failure is limited but does suggest a future role for beta-blockers as adjunct therapy in a select population of patients with heart failure.

Septal rupture: effect of oxygen administration

A patient with interventricular septal rupture as a complication of myocardial infarction was studied to determine whether varying the concentration of inspired oxygen would alter the magnitude of intracardiac shunt. A significant correlation was found showing that high concentration of inspired oxygen results in increased left to right shunting probably due to systemic vasoconstriction and pulmonary vasodilatation.

Epoprostenol (prostacyclin) in unstable angina

The purpose of this randomized, double-blind multicenter trial was to investigate the potential therapeutic effect of epoprostenol (prostacyclin, PGI2) in patients with unstable angina, as compared with placebo, and to investigate the safety of this agent. Of the 184 patients enrolled, 28 did not fit the study criteria; of the remaining 156 patients, 30 received prostacyclin in an open-label fashion. In the double-blind portion of the study, 63 patients each received prostacyclin or placebo. The drug or its vehicle was infused intravenously up to 5 ng/kg/min dose for 72 hours with a tapering off period for the last 12 hours. Both treatment groups from the double-blind portion were comparable in regard to the demographic data, length of infusion, and total dose received. There were no significant differences between the placebo and prostacyclin group in the following clinical endpoints: levels of cardiac enzymes throughout hospitalization period (with the exception of lower SGOT level in the prostacyclin group at day 2), and severity of angina (throughout the study), and at the end of the study (day 30). The number of patients who had congestive heart failure, new myocardial infarction, balloon pump insertion, coronary artery bypass grafting, or percutaneous coronary angioplasty was similar in both groups. Similar results in regard to the efficacy endpoints were also apparent in the prostacyclin group that was treated under open-label fashion. There was also no difference in the New York Heart Association (NYHA) functional status at the end of the double-blind study.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationship between location of chest pain and site of coronary artery occlusion

Chest pain characteristics and site of coronary artery occlusion were evaluated in 148 patients having single-vessel coronary angioplasty and in 95 patients having double-vessel angioplasty. The locations of chest pain included substernal and left precordium, right precordium and epigastric. The possible sites of pain radiation were limited to neck/jaw, left arm, right arm, and interscapular. The patient described whether or not the pain was typical of previous angina, and the presence of ST segment deviation was noted to be certain that ischemia was present. The analysis showed that the occluded artery could not be reliably identified. However, it was possible to say which artery was most likely not diseased. Patients presenting with substernal or left chest pain with radiation to the left arm had a less than 10% chance of having right coronary artery disease. A patient presenting with epigastric pain radiating to the neck or jaw had a less than 13% chance of having left anterior descending disease. It is concluded that in patients with single- and double-vessel coronary disease, there is some relationship between chest pain pattern and disease location.

Are 24 hours of ambulatory ECG monitoring necessary for a patient after infarction?

The Beta-Blocker Heart Attack Trial was a randomized clinical trial of propranolol versus placebo in 3837 patients after myocardial infarction. A 24 hour ambulatory ECG was obtained before therapy in 3290 patients 2 to 21 days after myocardial infarction. Sensitivity, specificity, positive and negative predictive values, and prevalence were calculated for four definitions of ventricular arrhythmia with either total or sudden death (death in less than 1 hour of observed symptoms) as an endpoint. These indexes were obtained using the first 1, 2, 4, 6, 12, and 24 hours plus a random hour, a random daytime hour, and a random nighttime hour of the 24-hour ECG of 1336 placebo patients. For both total death and sudden death, as the duration of monitoring increased, (1) prevalence increased, (2) sensitivity increased, (3) specificity decreased, (4) positive predictive value either changed very little or decreased, and (5) negative predictive value was high (greater than 90%) and increased slightly. None of the 3 random hours offered anything beyond the first hour. The Beta-Blocker Heart Attack Trial data, which were based on an average follow-up of 25 months, show that as the number of hours of ambulatory monitoring increase, the percentages of patients identified at risk or not at risk (the positive and negative predictive values) do not change much. Twenty-four hours of monitoring does not appear to be the optimal time duration for deciding whether to treat arrhythmias in patients after infarction.

The prognostic value of the duration of the ambulatory electrocardiogram after myocardial infarction

The purpose of this study was to examine the value of various durations of ambulatory ECG recording with regard to providing useful prognostic information. The authors explored a decision theoretic approach to determine the most useful period of monitoring for making a treatment decision based upon postulated benefit-to-risk ratios of antiarrhythmic therapies. They used data collected as part of the Beta-Blocker Heart Attack Trial (BHAT), a randomized clinical trial of propranolol versus placebo in 3,837 post-myocardial-infarction patients. In BHAT, 1,336 placebo-treated patients had a 24-hour ambulatory ECG that had at least 23 readable hours. Sensitivity and specificity were calculated for eight definitions of ventricular arrhythmia using either total mortality or sudden death (death within one hour of symptoms) as an endpoint. These indices were obtained using the first 1, 2, 4, 6, 12, and 24 hours plus a random hour, a random daytime hour, and a random nighttime hour of the 24-hour ECG of 1,336 placebo-treated patients. The study showed that in the case of high-risk, low-benefit therapies, no test is needed to make a treatment decision. No one should be treated. In the case of high-benefit, low-risk therapies, again, no test is required. Everyone should be treated. For therapies in the middle benefit-to-risk ratio range the most appropriate test for a treatment decision changes from the very specific to the most sensitive. Twenty-four hours of ambulatory monitoring is usually not necessary for a treatment decision, since four hours is likely to be sufficient.

Treatment of severe left ventricular dysfunction with calcium chloride in patients receiving verapamil

This report describes two patients who received verapamil because of supraventricular arrhythmias. The patients both developed severe hypotension and signs of left ventricular compromise. The hypotension and left ventricular compromise were promptly reversed by administration of intravenous calcium chloride. The dramatic improvement was documented clinically and in one case by two-dimensional echocardiography.

Reperfusion ventricular fibrillation during coronary artery bypass operations and its association with postoperative enzyme release

Elevated creatine kinase MB level is the most common marker of myocardial infarction in patients who have had a recent coronary bypass operation. This study was performed to determine whether there is any relationship between reperfusion rhythms, their treatment, and postoperative creatine kinase MB concentrations. Twenty patients were monitored during coronary bypass operations. Four patients had no reperfusion ventricular fibrillation and no elevation of creatine kinase MB postoperatively. Of the 16 remaining patients, all had ventricular fibrillation and 12 had an elevation of postoperative creatine kinase MB (p less than 0.015). There was also a 75% correlation between the time in ventricular fibrillation and postoperative creatine kinase MB level. There was no correlation between other measured parameters, such as cross-clamp time, bypass time, or the number of defibrillations. It is concluded that reperfusion ventricular fibrillation is associated with release of creatine kinase MB, and the time in ventricular fibrillation is correlated with the postoperative creatine kinase MB level.

Etiology and clinical significance of new fascicular conduction defects following coronary bypass surgery

Two hundred consecutive patients undergoing only coronary bypass surgery were studied. Forty-five patients (group A) developed new fascicular conduction blocks and 155 patients (group B) did not. The 45 patients in group A developed the following fascicular conduction blocks: right bundle branch block 47%, right bundle branch block and left anterior hemiblock 8%, right bundle branch block and first-degree atrioventricular block 2%, left anterior hemiblock 11%, left bundle branch block 18%, right bundle branch block-left anterior hemiblock and first-degree atrioventricular block 5%. There were no significant differences in sex, incidence of diabetes, number of grafts performed, ejection fraction (less than 55%), and perioperative infarction. Group A patients were older (p less than 0.01). Hypertension was found frequently in group A (27 vs 45 patients; p less than 0.01) and was present for a mean of 12.4 years in group A and 4.9 years in group B (p less than 0.01). Preoperative use of digitalis was found in 14 (31%) patients in group A and in 18 (12%) patients in group B (p less than 0.01). Twenty-one (47%) patients in group A had significant disease (greater than 70%) of the left main coronary artery as compared to 17 (10.9%) in group B (p less than 0.001). There was no difference in the recurrence of angina or the survival rate at 14 months. In conclusion, the incidence of new fascicular conduction block after bypass surgery is 22.5%. Long-standing hypertension, left main coronary disease, and the preoperative use of digitalis appear to be predisposing factors. New fascicular conduction block does not affect prognosis.

Postoperative ST-segment elevation in coronary artery bypass surgery

Using Holter monitors, 50 patients were monitored for vasospasm following coronary artery bypass surgery. Transient 2 mm ST-segment elevation was considered to be diagnostic or coronary vasospasm. Four patients (8 percent) had evidence of coronary vasospasm. Over 30 variables, including preoperative demographic information and medication, intraoperative technique, and postoperative medication, were subjected to multiple stepwise regression analysis. This analysis failed to show any association between preoperative prophylaxis with either nifedipine or nitrates (or other variables) and the postoperative development of coronary vasospasm. We conclude that the incidence of coronary vasospasm is more common than previously thought, and that a nifedipine or nitrate withdrawal, in this study, was not associated with an increased incidence of postoperative coronary vasospasm.

A fatal poisoning from an amatoxin containing Lepiota

The mushroom Lepiota josserandii Bon and Boif. has been identified as the cause of an unintentional, fatal intoxication in New York. The course of the symptoms, beginning with a 9 h latent period, was similar to what would be expected in a case of Amanita phalloides-type intoxication. Despite supportive medical care the victim expired 110 h after ingestion. Thin layer chromatography detected the presence of alpha- and gamma-amanitin and radioimmunoassay confirmed a level of 3.5 mg/gm dry weight of amatoxins in mushrooms from the same location.

Effect of propranolol in patients with myocardial infarction and ventricular arrhythmia

The Beta-Blocker Heart Attack Trial was a placebo-controlled, randomized, double-blind clinical trial of the long-term administration of propranolol hydrochloride to patients who had had at least one myocardial infarction. Among 3,837 patients followed up for an average of 25 months, 3,290 (85.7%) had 24 hour ambulatory electrocardiograms performed at the baseline examination. Four classifications of arrhythmia were examined. One of these, the presence of complex ventricular arrhythmias (at least 10 ventricular premature beats/h, or at least one pair or run of ventricular premature beats or multiform ventricular premature beats) was the subgroup of major interest. Regardless of the classification, the presence of arrhythmia identifies a group of patients with a higher risk of total mortality, coronary heart disease mortality, sudden cardiac death and instantaneous cardiac death. The a priori subgroup hypothesis that sudden death would be preferentially reduced by propranolol in patients with complex ventricular arrhythmias was not supported. The relative benefit of propranolol in reducing sudden death for this subgroup was 28 versus 16% for the subgroup without ventricular arrhythmia (relative risk of 0.72 versus 0.84, a nonsignificant relative difference of 14%). There were similar findings for two of the three other classifications of arrhythmia and for the other response variables. Although propranolol does not appear to be of special relative benefit in patients with ventricular arrhythmia, the presence of the arrhythmia does identify a high-risk group. The mechanism by which propranolol reduces mortality is still unclear, but is probably not solely an antiarrhythmic one.

Beta-Blocker Heart Attack Trial: impact of propranolol therapy on ventricular arrhythmias

The natural history of and the effect of propranolol on ventricular arrhythmias post-myocardial infarction were analyzed using data from the Beta-Blocker Heart Attack Trial (BHAT). The Beta-Blocker Heart Attack Trial was a multicenter, randomized, double-blind, placebo-controlled trial among 3,837 patients entered from 5 to 21 days after hospitalization for acute myocardial infarction. At baseline, prior to randomization, 3,290 (85.7%) patients underwent 24-hr ambulatory ECG monitoring which was repeated in approximately 25% of a randomly selected subset of the study population at 6 weeks. Ventricular arrhythmias were divided into eight different categories which defined the prevalence of ventricular arrhythmias in terms of frequency and/or complexity. Ventricular arrhythmias at baseline were associated with age, past history of myocardial infarction, and use of diuretics and digitalis. Paired data (baseline and 6-week) were available for 428 patients on propranolol and 412 on placebo. Propranolol markedly blunted the two- to threefold increase in ventricular arrhythmias that occurred from baseline to 6 weeks in the placebo group. Propranolol decreased the proportion of patients having ventricular arrhythmias during waking hours compared with sleep. These data show that propranolol has an antiarrhythmic effect and suggest that an antiarrhythmic mechanism may in part be responsible for the observed reduction in sudden cardiac death mortality in BHAT.

High mortality early reinfarction with first nontransmural myocardial infarction

Thirty-eight patients with first nontransmural myocardial infarction were studied to determine prognosis and clinical markers of a high-risk subgroup. We found a high incidence of reinfarction (18%) at a median time of 16 days post nontransmural infarction (seven patients). Reinfarction was uniformly associated with death within 24 hours. A total of 14 patients (37%) either died (eight patients) or required urgent revascularization (six patients). Predominant ST segment depression with presenting nontransmural infarction and a history of prior angina were associated with increased mortality (p less than 0.05 and p = 0.05, respectively). We conclude that patients with nontransmural infarction are at high risk for early recurrent infarction. Patients with history of prior angina and predominant ST segment depression may be at particularly high risk. Reinfarction in these patients is frequently extensive. We recommend that these patients be considered for early coronary angiography.

Dilated Cardiomyopathy in Identical Twins

Identical twins had dilated cardiomyopathy and evidence of an autoimmune process involving both the heart and thyroid gland. An inherited abnormality of immune regulation is suggested as a possible basis for these unusual findings.

Methemoglobin levels produced by organic nitrates in patients with coronary artery disease

To determine if ordinary doses of nitrates produce a significant increase in methemoglobin, methemoglobin levels were measured in 59 randomly selected patients with coronary artery disease and unstable angina pectoris who were receiving organic nitrate therapy. Patients were taking isosorbide dinitrate, 2% nitroglycerin ointment, or a combination of the two. Patients were subdivided according to whether they were using one (group A) or more than one (group B) organic nitrate preparations. These results were compared with 17 control patients. Mean methemoglobin levels in group B were 1.78 +/- 1.29%, and this differed significantly (P less than 0.05) from both group A mean methemoglobin, 1.13 +/- 0.92%, and controls, 0.99 +/- 0.55%. The proportion of patients with elevated methemoglobin concentration increased from the control to group A to group B. It is concluded that commonly used dosages of nitrates are capable of causing elevations of methemoglobin which are probably not of routine clinical significance. However, these elevations may be of import in certain patient populations such as those with coronary insufficiency or anemia.

Effect of propranolol in postinfarction patients with mechanical or electrical complications

In "post hoc" subgroup analyses, a simple classification system for patients, based on the presence or absence of findings indicative of electrical and/or mechanical complications early during short-term hospitalization, was applied to the data from the Beta-Blocker Heart Attack Trial (BHAT). In the largest subgroup of BHAT patients who had no reported complications, the 25 month mortality was low and the observed benefit of propranolol therapy small. Patients with electrical complications only had intermediate mortality and a pronounced effect of treatment was observed. Those with mechanical complications had the highest mortality and experienced an intermediate relative benefit of beta-blocker treatment. They also reported the most adverse effects. Post hoc analyses should always be interpreted cautiously. It is important to determine whether these findings are present in other completed beta-blocker trials. On the basis of these analyses alone it is suggested that the present practice of prescribing beta-blockers in postinfarction patients should not be altered.

Clinical significance of slow paroxysmal atrial tachycardia

This study examines the clinical setting, characteristics, and follow-up of 173 patients who had slow paroxysmal atrial tachycardia (SPAT) (greater than 4 beats, rate less than 150 bpm) during 24-hour Holter monitoring. These episodes were classified by probable mechanism according to recognized ECG criteria and included AV nodal reentry (AVNR), sinoatrial nodal reentry (SANR), and automatic (A). There were 76 males (44%) with a mean age of 72 years and 97 females (56%) with a mean age of 73 years. The indications for Holter recording revealed that the SANR and A subgroups had a higher frequency of cerebral symptoms compared to AVNR (p less than 0.01). Chest pain was more common in the SANR group as compared to the other two groups (p less than 0.01). There was no difference in the frequency of palpitation in the three subgroups. The mean rate of SPAT for the entire group was 115.2 +/- 14 and these episodes had a mean duration of 5.58 +/- 3.07 seconds. The SANR subgroup had a significantly slower rate (107.1 +/- 9.2) as compared to the AVNR subgroup (p less than 0.01). One hundred fourteen patients were available for follow-up. The average period of follow-up was similar for all three groups. At follow-up the frequency of sick sinus syndrome as determined clinically and permanent pacemaker insertion was significantly greater in the SANR subgroup (p less than 0.01) as compared to the other subgroups which did not differ from each other.