DM / DNB Cardiology Entrance Mock Test 8
This study found that though it is often associated with coronary artery disease (CAD), it can also occur in those without significant CAD. It was not specifically associated with disease of right coronary artery disease.
This cardioinhibitory response may be a manifestation of the Bezold-Jarisch reflex. Bezold-Jarisch reflex inhibits sympathetic activity (sympathetic withdrawal) and increases parasympathetic activity, resulting in bradycardia, which may be associated with vasodilatation, nausea and hypotension. Bezold-Jarisch has been described in the setting of inferior wall infarction and coronary angiography. Original description of Bezold-Jarisch reflex was of experimentally induced bradycardia with injection of veratrum alkaloids.
Paradoxical sinus deceleration may cause under detection of coronary artery disease due to the lower heart rates achieved. In those without evidence of myocardial ischemia, atropine is useful to counter the deceleration as well as to improve the chance of detection of an ischemic response. Administration of atropine during dobutamine stress echocardiography is standard procedure even in the absence of paradoxical sinus deceleration, if the target heart rates are not being achieved by dobutamine infusion.
Reference
1. Attenhofer CH, Pellikka PA, McCully RB, Roger VL, Seward JB. Paradoxical sinus deceleration during dobutamine stress echocardiography: description and angiographic correlation. J Am Coll Cardiol. 1997 Apr;29(5):994-9.
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Source: Cardiophile MD - Category: Cardiology Authors: Prof. Dr. Johnson Francis, MD, DM, FACC, FRCP Edin, FRCP London Tags: Cardiology MCQ Cardiology X-ray Featured Source Type: blogs
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