In this paper the cardiac actions of
adenosine, as well as its therapeutic and diagnostic applications are reviewed.
Adenosine has been demonstrated to be useful in the assessment of
coronary artery disease in conjunction with perfusion SPECT scintigraphy, PET imaging and two-dimensional echocardiography. The reported sensitivities and specificities of
adenosine in these settings are high and similar to those of imaging after exercise or
dipyridamole induced coronary
hyperemia. Minor side effects are commonly associated with
adenosine infusion, however they are transient, generally well tolerated, and rarely require test termination or the administration of
aminophylline.
Adenosine has proven very useful in the noninvasive diagnosis of
Wolff-Parkinson-White syndrome and in the localization of the ventricular insertion of the accessory pathway. As a provocative test,
adenosine 12.0 mg rapid bolus has a sensitivity and specificity of 100% for identifying anterograde atrioventricular accessory pathway conduction. The use of
adenosine is particularly well suited to the technique of echocardiographic phase analysis and cine-loop inspection as image acquisition is rapid and may be obtained on-line. Although the only approved
therapeutic use of
adenosine is in the
emergency treatment of
paroxysmal supraventricular tachycardia, several other clinical applications are suggested by the agents specific cardiovascular and electrophysiologic properties. These include 1. post-
thrombolytic therapy to reduce
reperfusion injury, 2. as an afterload reduction agent in
malignant hypertension and
congestive heart failure, 3. to produce
controlled hypotension intraoperatively during vascular procedures, and 4. to terminate
catecholamine and exercise mediated
ventricular tachycardia. Furthermore, the technique of
adenosine echocardiographic phase analysis offers the potential for precise subsegmental localization of accessory pathways which has never been achieved by any noninvasive technique, and
adenosine augmentation of preexcitation obviates the need for invasive cardiac pacing. Future applications of
adenosine scintigraphic and echocardiographic methods will undoubtedly involve newer imaging modalities, such as multiplanar transesophageal and magnetic resonance imaging, which may improve our current abilities to localize accessory pathways and noninvasively diagnose
coronary artery disease.