Heart attack, by definition, is when there is damage to the heart muscle; as in someone is ‘attacking’ the heart. The most common cause is blockages to blood vessels that supply blood to the heart. Depending on the severity of the blockage and extent of muscle damage, a heart attack can be classified as minor or major; although it may be argued that every heart problem is a major problem. The symptoms of a Heart attack may includes chest or jaw discomfort, breathing difficulty etc. Anyone with such symptoms should seek prompt medical attention. Treatment of heart attack is aimed towards restoring the blood flow to the heart, which is best achieved by urgent angioplasty.
Cardiac arrest, by definition, is when there is a loss of meaningful heart activity. A person with cardiac arrest will be unconscious without any pulse and likely without any spontaneous breathing. If no immediate life-saving measure is undertaken, a person with cardiac arrest will not survive beyond a few minutes. Cardiac Arrest occurs when there is an electrical dysfunction of the heart. The heart rate may go exceedingly fast (typically more than 180 beats per minute) rendering each heartbeat ineffective or extremely slow (less than 30 beats per minute) leading to insufficient blood flow out of the heart. The most common scenario leading to cardiac arrest is when the heart is beating too fast, a condition called Ventricular Tachycardia (VT) or Ventricular Fibrillation (VF), and is usually due to a heart attack. Treatment of cardiac arrest is to perform an immediate bystander Cardio-Pulmonary Resuscitation (CPR). CPR involves chest compressions, external breathing support (for example mouth to mouth breathing), and delivering an electrical shock to the heart (defibrillation) using an Automated External Defibrillator (AED). Once spontaneous heart activity and breathing are restored, further treatment is aimed at finding and treating the cause of the cardiac arrest.
In summary, a heart attack is a blood flow problem. Usually, the patient is awake and there is enough time that the patient can be brought to the nearest emergency room. Treatment is an urgent angioplasty. With quick and efficient treatment, survival can reach up to 90%. Cardiac arrest is an electrical problem. The patient is always unconscious and cardio-pulmonary resuscitation needs to be started immediately. Even with the best of the efforts, the overall survival is less than 10%.