Clinical and Electrophysiological Characteristics of Atrial Standstill

Abstract

To clarify the clinical and electrophysiological characteristics of atrial standstill (AS) we studied 11 patients (7 males and 4 females), whose average age was 62 years and who were followed over a period of 4-179 months. Underlying heart disease was present in nine patients and two cases were idiopathic. Major clinical symptoms in the 11 cases included Adams-Stokes attacks, and dyspnea on exertion. In the standard 12-lead ECGs obtained on admission, the P wave was absent in six cases. Atrial flutter (AF) was noted in 3, atrial fibrillation (Af) in 1, and multifocal atrial tachycardia in 1. In some cases, the ECG initially showed AF or Af, and was transformed after several years into ectopic atrial tachycardia or an ectopic atrial rhythm with a markedly decreased amplitude of the P wave. Finally, the P wave disappeared over a prolonged period. When intracardiac mapping was performed, the atrial electrograms tended to diminish at the site of high, mid-lateral right atrium (RA). Electrograms were remained present in the vicinity of the tricuspid valve (TV) annulus. A repeated mapping and pacing study conducted in two patients revealed that the "silent" area spread toward the lower site of RA. During the average follow-up period of 64 months, four patients died. The interval until death in one patient with myocarditis was 6 months, and in another with dilated cardiomyopathy (DCM) it was 8 months. It appears that the atrial muscular lesion starts in the high lateral RA and progresses toward the lower RA, then to the vicinity of the TV annulus. A diffuse and progressive disturbance may occur not only in the atrial muscle, but also in the atrioventricular conduction system in patients with AS who had progressive myocarditis or DCM.

Atrial Standstill with Subnodal Conduction Defect and Diffuse Ventricular Fibrosis Managed with Low Right Atrial Pacing

“…1−6 Similarly, the coexistence of atrial standstill with serious AV conduction abnormalities has also been described. 4,5 This collection of electrophysiological abnormalities, namely the presence of atrial standstill with localized electrical activity in a small low right atrial region along with the delayed AV node, Hisbundle and infra-His conduction defects underlined the bradyarrhythmia symptomatology of the patient with the history of surgically repaired single atrium and pulmonary valvuloplasty.…”

Ebstein's anomaly, atrial paralysis and atrio-ventricular block: an uncommon association

“…Other series have demonstrated 'mechanical atrial failure' as a specific entity with some persistent electrical but no mechanical activity. This phenomenon has been associated with ventricular dysfunction or with surgical procedures [5] . The presence of mechanical atrial failure with sporadic electrical activity could be a feature of cardiomyopathy, but the lack of heart failure symptoms in this patient makes it an unlikely possibility.…”

Autosomal Recessive Atrial Dilated Cardiomyopathy With Standstill Evolution Associated With Mutation of Natriuretic Peptide Precursor A

“…Complete AS was defined as absence of atrial electric activity on surface ECG, with junctional bradycardia, absence of atrial activity in endocavitary recordings, no response to stimulation during electrophysiological study, and absence of A wave by echocardiography. 9,14 Partial AS was defined as absence of atrial electric activity on surface ECG, but with still irregular junctional rhythm and only localized absence of endocavitary atrial activity and no response to stimulation. Carto electroanatomic mapping was performed in 5 patients (Biosense-Welbster, Diamond Bar, CA): the areas displaying electric atrial activity <0.05 mV at bipolar mapping were considered scars.…”