The pacemaker syndrome is a complex of symptoms consisting of heart failure, near fainting, sensations of pulsation in the neck or abdomen or cough which develop or are aggravated after cardiac pacing. Objectively, a fall in systolic blood pressure is observed in the majority of cases and also canon waves in the neck veins, signs of heart failure, retrograde arterial activation and possibly canon-a-awaves in the central venous pressure. The syndrome occurs in approximately 15% of the patients with ventricular pacing. The condition is most probably caused by lack of atrioventricular synchrony with resultant distension of the atria which results in a reflex mediated decrease or defective increase in the total peripheral resistance and, thus, a fall in systolic blood pressure. Treatment consists of establishing normal atrioventricular synchrony either by implantation of an atrial or AV-sequential pacemaker or by re-programming so that the patient has, primarily, his own rhythm. Ensuring normal atrioventricular synchrony has also other advantages as several investigations have shown that 60-80% of the patients prefer this form of pacing rather than ventricular pacing. The working capacity improves and the patients feel subjectively better and the risk for development of chronic atrial fibrillation and heart failure decreases.