Familial endemic persistent atrial standstill in a small mountain community: review of eight cases.

Familial persistent atrial standstill (PAS) has been rarely documented. Five patients, three male and two female (mean age 46 years at first observation), with familial 'complete' PAS, all from a small mountain community (900 residents) have been studied. Diagnostic criteria were: absence of P wave in any lead of the standard electrocardiogram; no electrical activity of the atria with extremely slow junctional escape rhythm on the endocavitary recordings; lack of atrial excitability; absence of atrial wall movement at fluoroscopy; no mitral A wave on the echocardiogram. All patients had marked cardiac enlargement primarily due to atrial enlargement and all had impaired functional class. Some had bradycardia for many years but none had syncope. Permanent cardiac pacing was carried out in all. Two had cerebral embolism. In the same community there were three patients, one male and two female (mean age 34 years at first observation), with 'partial' atrial standstill characterized by absence of P waves in any lead of the standard electrocardiogram and by endocavitary recording of electrical activity limited to a localized region of the atrium. These three patients also had cardiac enlargement primarily due to atrial enlargement but to a lesser degree than the patients with complete PAS. One patient had cerebral embolism. The familial and endemic character of the disease is stressed. Cardiac enlargement due primarily to atrial enlargement seems to be a common feature of both the complete and partial form of the PAS syndrome.