Akademik

a heartbeat due to an impulse generated somewhere in the heart outside the sinoatrial node. Ectopic beats are generally premature in timing; they are classified as supraventricular if they originate in the atria and ventricular if they arise from a focus in the ventricles. They may be produced by any heart disease, by nicotine from smoking, or by caffeine from excessive tea or coffee consumption; they are common in normal individuals. The patient may be unaware of their presence or may feel that his heart has 'missed a beat'. Ectopic beats may be suppressed by drugs such as quinidine, propranolol, and lidocaine; avoidance of smoking and reduction in excessive tea or coffee intake may help. See arrhythmia.