Effect of the Antiarrhythmic Agent Moricizine on Survival after Myocardial Infarction | NEJM

Six major changes were made to the protocol in CAST-II. 9 First, the sketch was continued with moricizine, and no modern antiarrhythmic drugs were added. Second, the upper limit of eligible values for bequeath ventricular ejection divide ( measured by radionuclide ventriculography in 39 percentage of patients, by echocardiography in 29 percentage, and by angiography in 32 percentage ) was lowered from ≤0.55 — the original cutoff point in CAST-I — to ≥0.40. Third, the distance of time from the qualifying myocardial infarct to the qualifying ambulatory electrocardiographic commemorate was shortened from 2 years or less — the time interval used in CAST-I — to 90 days or less. Fourth, disqualifying ventricular tachycardia was redefined to exclude from the trial patients with any runs lasting 30 seconds or longer at a rate of ≥120 complexes per minute, but to allow the registration of patients with repetitive ventricular complexes of ≥15 beats and lasting up to 30 seconds without symptoms ( such patients were excluded from CAST-I ). Fifth, a higher dose of moricizine ( 900 mg per day ) was permitted if needed to suppress 80 percentage of ventricular previous depolarizations. finally, because there were no controlled data on the initiation of drug discussion in CAST-I, CAST-II began with a two-week master trial of the early effects of low-dose moricizine. CAST-II therefore focused on patients who were more likely to benefit from antiarrhythmic therapy. recruitment was to continue until January 1, 1992, by which clock it was expected that 2200 patients would have been enrolled in the two-week test and 2100 patients would have been enrolled in the long-run trial. Follow-up was scheduled to continue until April 1, 1994. In CAST-II, new patients ( first screened after April 19, 1989, to determine their eligibility ) were considered eligible if an ambulatory electrocardiographic read obtained 4 to 90 days after an acute myocardial infarct demonstrated at least six ventricular previous depolarizations per hour and if the left ventricular ejection divide was ≤0.40. The phase of long-run therapy in CAST-II included 1374 patients whose arrhythmias were suppressed or partially suppressed by moricizine. The patients came from four alike groups : 320 patients had been treated with moricizine or its placebo in CAST-I and simply continued their put treatment in CAST-II ; 40 patients in whom the acid of antiarrhythmic-drug treatment was being titrated when CAST-I was stopped completed the serve of titration with moricizine and consented to randomization ; 216 patients who had been assigned in CAST-I to receive encainide, flecainide, or placebo and whose arrhythmias persisted after the discontinuance of their assigned treatment were subsequently enrolled in CAST-II, given moricizine to determine whether it would suppress the cardiac arrhythmia, and randomly assigned to receive moricizine or its placebo ; and 798 new patients who met the criteria for CAST-II, and after titration of the drug acid, were randomly assigned to receive moricizine or its placebo.

The short-run test included 897 patients ( 887 new patients a well as 10 patients from CAST-I who had been receiving encainide, flecainide, or placebo and who qualified for CAST-II ) who were randomly assigned to receive either low-dose moricizine ( 200 magnesium every eight hours ) or its equal placebo for two weeks. The effects of short-run discussion with moricizine were assessed in an extra 428 patients ( enrolled after April 19, 1989, but before the versatile institutional review boards had approved a change to a placebo-controlled two-week trial ) by randomly assigning 211 of the patients to begin immediate assessment receiving moricizine and 217 to receive neither moricizine nor placebo for two weeks. After two weeks, the treatment assignments were unblinded ( if placebo-controlled ) and patients who had been treated with moricizine were evaluated by ambulant electrocardiographic recording to determine whether ventricular premature depolarizations were adequately suppressed. Patients who had received placebo or in whom the initiation of therapy was delayed began to have the venereal disease of moricizine titrated and were subsequently evaluated by ambulatory electrocardiographic record. suppression of cardiac arrhythmia was deemed adequate if at least 80 percentage of ventricular premature depolarizations were suppressed and if at least 90 percentage of the runs of nonsustained ventricular tachycardia were suppressed. titration had to be accomplished within 90 days of the qualifying ambulatory electrocardiographic record and began with a dose of 200 mg three times casual. If the initial dose did not produce adequate inhibition, a second dose ( 750 mg per day ) and, if necessity, a third drug ( 900 mg per day ) were used arsenic long as they were not accompanied by disqualifying adverse effects or symptoms. Patients in whom ventricular premature depolarizations and runs of nonsustained ventricular tachycardia were adequately suppressed were randomly assigned to receive moricizine or its match placebo in the chief study. Patients in whom cardiac arrhythmia were entirely partially suppressed were enrolled in a substudy and randomly assigned to receive moricizine or placebo. Patients in whom arrhythmias either were not suppressed or were increased were not assigned to a study group, although they were still followed. The basal end point for the short-run, low-dose study was death or cardiac check within the two-week period. The basal end point of CAST-II for the independent analyze and the substudy was death due to arrhythmia or cardiac arrest due to arrhythmia requiring resuscitation. 7 8 9 10 All events were reviewed by a subcommittee of investigators who were unaware of the treatment-group assignments.

All patients gave informed consent for this sketch. The research protocol was approved by each center ‘s institutional review board.

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Statistical Analysis

statistical analyses were performed independently for the low-dose, short-run phase and for the long-run treatment phase in order to determine the risk associated with the trigger of therapy and the benefit or hazard associated with long-run therapy. Analyses were conducted according to the principle of intention to treat. Though patients given moricizine or its placebo came from the four subgroups outlined above, their data were pooled because the general characteristics of the groups were similar ( all had a history of myocardial infarct, ectopic beats, and reduce ejection fractions ), and randomization was stratified according to subgroups. The two-week, low-dose trial was evaluated with a one-tailed trial with an α flat of 0.05 ( during this menstruation, patients were monitored only for the occurrence of harmful effects ; testify of profit would not in itself have been a rationality for stopping the trial ). The results of two-tailed tests are besides reported. A permutation test based on the randomization assignment ( with the chi-square statistic ) was employed. 11

During the long-run phase of the CAST-II study, separate evaluations assessed the effects of moricizine and placebo in patients with adequate suppression of cardiac arrhythmia and the effects of moricizine and placebo in patients with only partial derivative suppression of cardiac arrhythmia. The long-run learn was monitored for both injury ( α tied, 0.05 ) and benefit ( α level, 0.025 ). A permutation trial based on the randomization grant ( with the log-rank statistic ) was employed. 12 The permutation quiz took into account the assorted strata imposed by the protocol and by the changes in the protocol from CAST-I to CAST-II. Both phases of the survey used consecutive monitoring techniques, and the final P values considered to indicate statistical significance were adjusted accordingly. 13 The conditional world power of the tests was besides evaluated regularly to assist in monitoring the progress of the analyze and the advisability of continuing the trial. 14 An independent Data and Safety Monitoring Board reviewed the data at six-month intervals. They evaluated the potential benefit of and injury from the therapy and the likelihood that the test would yield meaningful and statistically meaning data, based on progress of the report. Decisions were based in contribution on analyses of conditional power — that is, the gamble of observing profit given the accumulate information. 12 13 14 At its April 1991 meeting, the circuit board decided, on the footing of the evolving trends in the datum, to schedule a suffer in three, quite than six, months. This meet occurred in July 1991.

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