Warning signs are common in the days before cardiac arrest but are often ignored.

Warning signs frequently occur in the days and weeks before a sudden cardiac arrest but are mostly ignored, research published in the Annals of Internal Medicine has found. US researchers collected information about symptoms during the four weeks before a sudden cardiac arrest from 1099 people in the Portland, Oregon area. Information was gathered from survivors, family members, medical records, and emergency response records. The mean age of the patients was 52.6, and three quarters were men. Information about symptoms was not available from about a quarter of the patients. Of the 839 patients with information available, around half (430) had experienced warning symptoms during the four weeks before their sudden cardiac arrest. The main symptomwas chest pain, which was documented in 199 patients (46%), 151 of whom had intermittent typical angina. Dyspnoea was present in 78 patients, and syncope or palpitations were found in 22. In most symptomatic patients (93%), symptoms recurred within the 24 hours before their cardiac arrest. However, only 81 patients (19%) called emergencymedical services to report their symptoms. Those patients who did report their symptoms were more likely to have a history of heart disease (P<0.001) or continuous chest pain (P<0.001), probably because of better awareness of warning signs. And patients who called the 911 emergency number significantly increased their chances of survival: 32.1% (95% confidence interval 21.8% to 42.4%), compared with 6.0% (3.5% to 8.5%) in those who did not call emergency services (P<0.001). The study found that the overall frequency of symptoms was similar between men and women. However, the pattern of symptoms differed significantly: men experienced more chest pain than women, whereas women experienced more dyspnoea. The researchers said, “Our findings emphasise the need to encourage efforts that target public awareness of sudden cardiac arrest as a largely fatal event. It is important to reinforce knowledge of prodomal symptoms of sudden cardiac arrest in the general public and in patients affected by heart disease and their family members.”