A yearlong review of 406 cardiac arrest cases indicates that most patients experience symptoms, lasting between 5 minutes and 2 hours, before 90% of arrests. Although 25% of patients surveyed reported no warning signs, 22% said their arrests were preceded by chest pain, 15% had difficulty breathing, 12% experienced nausea or dizziness, and 8% reported other symptoms. The majority of patients observed had a history of cardiac risk factors, such as diabetes, smoking, or pulmonary disease. Researchers also concluded that 67% of arrests occur in view or hearing of another person, usually a member of the patient's family. However, patients and witnesses often don't realize the significance of the warning symptoms. Cardiopulmonary resuscitation (CPR) was initiated in 57 cases, of which 23% survived. In the 349 cases where no CPR was performed, only 4% of patients survived. Researchers recommend that all at-risk patients and their relatives be given education about symptoms that precede cardiac arrest and basic life support training to increase the likelihood of recognizing and surviving an arrest.

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