History
History is helpful for identifying the underlying etiology for AIVR. The presence of the following conditions supports a potential diagnosis of AIVR:
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Most patients with AIVR have chest pain or shortness of breath, symptoms related to myocardial ischemia. They often have recent history of myocardial reperfusion with drugs or coronary artery interventions. [16]
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Some patients with AIVR have chest discomfort, shortness of breath, peripheral edema, cyanosis, clubbing, symptoms related to cardiomyopathy, myocarditis, and congenital heart diseases.
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Occasionally, patients with AIVR have history of using digoxin, some anesthetic agents, or illicit drugs such as cocaine.
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Rarely, AIVR can occur in people without apparent heart disease and no identifiable triggers.
Physical
There are no specific physical findings for AIVR. The following physical signs may be present:
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Slow (< 55 bpm) or fast (>100 bpm) pulse rate.
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Variable heart sound intensity and cannon A waves related to atrioventricular dissociation.
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Some irregularity of heart rate/pulse rate due to competing sinus rhythm and AIVR.
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Rarely, hypotension related to either AV asynchrony or relatively rapid ventricular heart rate during AIVR.
Causes
The AIVR can occur in people with and without apparent heart diseases. [17] The most common cause of AIVR is myocardial ischemia-reperfusion. Other causes include the following:
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Buerger disease [18]
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Congenital heart disease [19]
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Dilated cardiomyopathy [4]
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Myocarditis [10]
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Electrolyte abnormality
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Postresuscitation [15]
Beach et al reported on the case of a boy aged 4 years who appeared to have developed AIVR from the administration of inhaled albuterol to treat his status asthmaticus. [23]
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AIVR and sinus rhythm: AIVR starts and terminates gradually, competing with sinus rhythm. A possible ventricular fusion beat (arrow) and isoarrhythmic AV dissociation (arrowheads: sinus P waves) are present. During AIVR, ectopic ventricular rate is just faster than sinus rate. AIVR has a wide QRS morphology different from the QRS morphology in sinus rhythm.
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AIVR in atrial fibrillation: AIVR starts and terminates gradually, competing with the ventricular capture beats (arrow) from atrial fibrillation. Ventricular fusion beat (arrowhead) is present. AIVR has a wide QRS morphology different from the QRS morphology of ventricular capture beats.
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Complete heart block with escaped junctional rhythm: The AV dissociation in complete heart block is not isoarrhythmic AV dissociation, because the atrial rate is much faster than the escaped junctional ventricular rate.
