Diagnostic criteria of atrial standstill

  Absent P waves both on surface and intracardiac ECG.

  Junctional bradycardia.

  Lack of response of the atria to direct electrical stimulation.




Atrial standstill may be observed in patients with

  Coronary artery disease

  Acute myocardial infarction

  Congestive heart failure

  Amyloidosis

  Drug intoxication (digitalis, verapamil, quinidine, proscillaridin)

  Isolated noncompaction of right ventricular myocardium

  Hypoxia

  SCN5A mutation

  Ebstein's anomaly

  Idiopathic right atrial dilatation

  Emery-Dreyfuss muscular dystrophy

  Kugelberg-Welander syndrome (spinal muscular atrophy Type III)

  Myocarditis




Atrial standstill

  Atrial standstill may be partial or complete.

  Partial atrial standstill
: failure of atrial activity either spontaneously or in response to electrical

      stimulation
in restricted site of atria (diagnosed by electrophysiological study).

  On surface ECG, left atrial standstill may be obscured by the right and left atrial electrical dissociation.

  Atrial standstill may be persistent or reversible.

      Prolonged, but reversible atrial electrical silence may follow abrupt termination of

      chronic atrial tachycardias (atrial flutter, ectopic atrial tachycardia)

  It has been suggested that
endocrinologic silence (disturbed secretion of atrial natriuretic peptide)

      accompanies electrical and mechanical silence of the atria during atrial standstill.

  It must be differentiated from fine atrial fibrillation.

      Unlike atrial fibrillation, there is no oscillating baseline in atrial standstill.




Arrhythmia syndromes associated with mutations in the SCN5A gene (encoding the major
sodium channel in heart) are


  Long-QT syndrome type 3 (LQTS3)

  Brugada syndrome

  Sinus node dysfunction

  Conduction disease

  Atrial standstill




References

  PACE 2007;30:1311-1315.

  Journal of Electrocardiology 2005;38:252-255.

  Pacing Clin Electrophysiol 2002;25:217-219.

  PACE 2008;31:509-512.

  Europace 2002;4:451-454.

  J Am Coll Cardiol 1991;18:459-463.

  Trends Cardiovasc Med 2008;18:78-87.

  International Journal of Cardiology 2008;131:e14-e16.

  International Journal of Cardiology 1999;70:207-210.

  Progress in Cardiovascular Diseases 2010;52:347-361.

  Journal of Cardiology Cases 2010;2:e52-e54.

  Jpn Circ J 1996;60:382-388.