The heart beating hard after drinking alcohol is caused by sympathetic nerve excitation, the effect of alcohol metabolizing substances and low blood sugar. 1. Sympathetic excitation: alcohol will stimulate the body’s nervous system, resulting in increased excitability of the sympathetic nerves, in the sympathetic over-excitement of the increased tension, the patient will have a rapid heartbeat. 2. Metabolites: ethanol in alcohol will be converted into acetaldehyde, acetaldehyde in the case of capillary dilation, will reflexively cause tachycardia, for the past clear coronary heart disease or angina pectoris patients, especially in the drinking of alcohol after the tachycardia symptoms are particularly obvious. 3. Hypoglycemia: Consuming a large amount of alcohol will also block the absorption of glycogen by the liver, which may cause hypoglycemia and tachycardia. If your heart continues to beat faster after drinking alcohol, accompanied by discomfort in the precordial area, seek medical attention to rule out disease.