Editor—Freemantle et al show good evidence that long term β blockade is an effective and well tolerated treatment that reduces mortality and morbidity in unselected patients after myocardial infarction.1 They present data for the end points all cause mortality and non-fatal reinfarction but make no specific reference to sudden death. They quote the results of 31 long term trials; we have been able to find data on sudden death in only 13 of these.
Sudden death is common and an important cause of death in the major long term trials after myocardial infarction. In the 13 trials that included data on sudden death the average incidence of sudden death in the placebo treated group was 51% (table). The corresponding figure in the groups treated with a β blocker was 43%. Although this suggests that β blockers do reduce the risk of sudden death, these mean figures probably grossly underestimate the potential impact of β blockers.
For interest, the table also shows results from the two largest trials, the Norwegian trial2 and the β blocker heart attack trial.3 The two drugs used in these trials, timolol and propranolol, are lipophilic non-selective β blockers and seemed to reduce the risk of sudden death. In the two recently reported β blocker heart failure studies the reduction in sudden death rates was even greater. Bisoprolol (in the cardiac insufficiency bisoprolol study II4) and metoprolol (in the metoprolol CR/XL randomised intervention trial in congestive heart failure5) decreased sudden death rates by 42% and 41% respectively.
Therefore we agree that β blockers have a key role in reducing the morbidity and mortality after myocardial infarction. There is also an important but less well recognised role for these agents in reducing the incidence of sudden death, which may account for half of the deaths in such patients.