Junctional Rhythm Clinical Presentation
- Author: Sean C Beinart, MD, FACC, FHRS; Chief Editor: Jeffrey N Rottman, MD more...
History
Junctional rhythms may be accompanied by symptoms or may be entirely asymptomatic.
- Palpitations, fatigue, or poor exercise tolerance: These may occur during a period of junctional rhythm in patients who are abnormally bradycardic for their level of activity.
- Dyspnea: Sudden onset of symptoms and sudden termination of symptoms may occur, especially in the setting of complete heart block.
- Presyncope (near syncope): The underlying cause of the junctional rhythm is the most significant predictor of symptoms. For instance, AV dissociation with complete heart block, defined as an atrial rate that is faster than the junctional escape rate, is more likely to cause symptoms than AV dissociation with a sinus rate slower than the competing junctional pacemaker. Additionally, syncope or presyncope may occur from an acute decrease in heart rate.
Physical
- A predominant junctional rhythm may be associated with structural heart disease, sick sinus syndrome, or both, during which the junctional escape rhythm supersedes the sinus rate and provides a safety mechanism.
- During a predominant junctional rhythm, the pulse usually is regular and the heart rate may be within reference range. Frequently, the junctional rhythm is 40-60 beats per minute.
- Prominent jugular venous pulsations (ie, cannon a waves) may be present due to the right atrium contracting with a closed tricuspid valve.
Causes
- Sick sinus syndrome (including drug-induced)
- Digoxin toxicity
- Ischemia of the AVN, especially with acute inferior infarction involving the posterior descending artery, the origin of the AV nodal artery branch.
- Acutely after cardiac surgery, especially in children within 4 days after surgery for congenital cardiac defects
- Acute inflammatory processes (eg, acute rheumatic fever, lyme disease), which may involve the conduction system
- Diphtheria
- Other drugs (eg, beta-blockers, calcium blockers, most antiarrhythmic agents) that cause sinus bradycardia
- Metabolic states with increased adrenergic tone
- Isoproterenol infusion
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Daubert JP, Rosero SZ, Corsello A. Tachycardias. In: Rakel RE, Bope ET, eds. Conn's Current Therapy. New York, NY: WB Saunders; 2001:286-95.
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