Blackouts and faints are the temporary loss of consciousness. This may be due to a sudden loss of blood supply to the brain, known as ’syncope’, and can be due to a problem with blood pressure or heart function. Evaluation by a cardiologist is critical, and will include investigation of possible arrhythmias, congenital heart disease or cardiomyopathy. A syncope specialist will do a physical exam and a careful review of your medical history, and may assess your heart rate and blood pressure while you’re in different positions. Other tests may also be required such as an ECG and echocardiogram.