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AV junctional tachycardia

A non paroxysmal condition with narrow complex & regular rhythm @ 60-130/min thought to arise from increased automaticity of the AV node. Etiology: 1) myocardial infarction 2) catecholamine excess 3) digitalis toxicity 4) post cardiac surgery 5) rheumatic fever Special laboratory: - electrocardiogram: a) atrial rate generally 60-130/min b) intact retrograde conduction - p-waves a] inverted b] occur during or immediately after the QRS complex c) retrograde conduction block 1] competitive AV dissociation 2] normal p-waves non-conducted at a rate slower than ventricular rate d) ventricular rate 60-130/min 1] QRS may be normal 2] QRS may reflect bundle-branch block secondary to increased rate Management: 1) arrhythmia generally resolves with correction of underlying precipitating factors - discontinue offending pharmacologic agents a) exogenous catecholamines b) digitalis 2) anti-arrhythmic agents a) phenytoin or lidocaine for digitalis toxicity b) beta blocker, Ca+2 channel blocker c) amiodarone is drug of choice is LCEF < 40% 3) NO DC cardioversion 4) K+ for digitalis toxicity 5) Mg+2 supplementation 6) atrial overdrive pacing in patients with hemodynamic compromise in setting of competitive AV dissociation 7) catheter ablation

General

AV junctional rhythm narrow complex tachycardia

Figures/Diagrams

EKG: junctional tachycardia

References

  1. Manual of Medical Therapeutics, 28th ed, Ewald & McKenzie (eds), Little, Brown & Co, Boston, 1995, pg 142
  2. Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 273
  3. American Heart Association