Laboratory Studies
Blood tests
Obtain levels of troponin, CK and CK-MB for the diagnosis of myocardial infraction.
Obtain BUN and creatinine measurements to assess renal function in patients with suspected digoxin toxicity.
Other laboratory tests
Obtain levels of digoxin and electrolytes.
Imaging Studies
Obtain echocardiography to evaluate structural heart diseases.
Nuclear perfusion scanning is used to evaluate myocardial ischemia.
Coronary angiography is used to evaluate coronary artery patency.
Other Tests
Electrocardiography is the most important method for the diagnosis of accelerated idioventricular rhythm (AIVR); AIVR can be distinguished from complete heart block on ECG. [27] Although both show AV dissociation, in complete heart block, P waves are present preceding the QRS complex, but fail to conduct to the ventricle.
Telemetry monitoring, Holter study, event recorder, and loop recorder are often the electrocardiographic modalities from which AIVR diagnosis is established.
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Accelerated Idioventricular Rhythm. 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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Accelerated Idioventricular Rhythm. 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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Accelerated Idioventricular Rhythm. 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.