In 1980 a cardiologist in Nottingham named Alan Cowley carried out a small clinical trial of a drug called Lorcainide. It was known at the time that heart attacks could cause irregular heartbeats in patients (known as arrhythmia), and these arrhythmias often lead to early death. Lorcainide had been shown to suppress arrhythmia, so it made sense that patients who came to hospital with a heart attack should be treated with the drug. Cowley and his colleagues carried out a small trial with 95 patients, and tested them to see whether they were getting more or fewer arrhythmias. The drug worked, lowering the frequency of serious arrhythmia.
The doctors noticed something else however. Of the 48 patients on the drug, 9 had died, compared to only 1 patient on the placebo. This was a very small trial, so the doctors weren’t overly alarmed. It’s not surprising that 10 patients died in the study; these are patients who are presenting with heart attacks after all. It was just worrying that there was such an imbalance between the groups. The doctors chalked it up to bad luck, and viewed their trial as a success.