A normal person who has a heart attack will not die. Because normal people may experience cardiac arrest when they smoke, drink alcohol or coffee, or when they are emotionally disturbed, it is usually caused by premature beats and will not be a problem, as long as they quit or reduce the amount. It is not a problem if there is no organic heart disease, but if it occurs with organic heart disease, myocardial ischemia or acute myocardial infarction, it can be life-threatening and may induce malignant arrhythmia and sudden death. If it is accompanied by sudden loss of consciousness during cardiac arrest, it may be the occurrence of A-Syndrome, which is also dangerous. If the cardiac arrest occurs during digitalis, it may be due to digitalis toxicity and should be stopped and treated with potassium supplementation, otherwise it may also be life-threatening.