Reciprocal impulses in patients with extrasystolia

In 300 patients with extrasystolia and 36 patients with parasystolia a systematic search for reciprocal impulses was conducted with the aid of oesophageal ECG leads. Within 10-min periods, reciprocal impulses were detected in 13 patients (3.9 per cent). Reciprocal impulses occurred in extrasystolias of both functional and organic origin. Exercise contributes to the appearance of postextrasystolic reciprocal impulses. After intravenous injection of 10 mg Obsidan (propranolol hydrochloride) the phenomenon was less marked; in two patients, Obsidan oral medication (40 mg three times daily) led to the disappearance of reciprocal supraventricular paroxysmal tachycardia elicited by ventricular extrasystolia.