Abnormal heart rate response with vasodilator stress myocardial perfusion imaging: Relevance to clinical practice

Excerpt

Myocardial perfusion imaging (MPI) is a commonly used test in the evaluation of patients with suspected or known coronary artery disease. Over the past two decades, it has emerged from a simple diagnostic test to assess the presence or absence of obstructive coronary stenosis into a much more powerful test with multiple applications. Its prognostic power in different patient populations has now been established in multiple studies.1,2 Furthermore, it is now also commonly used to assess and quantify the efficacy of medical or invasive interventions.3 Although the presence and extent of perfusion defects have been the standard prognostic variables in MPI, several other non-perfusion variables were also shown to add to its prognostic power. When done in conjunction with exercise, the exercise duration and associated ischemic changes become significant added prognostic variables. When done in conjunction with pharmacologic stress, other variables have also been shown to add prognostic power to the test. Just recently, Bajaj et al4 published in the journal an extensive review on the non-perfusion prognostic variables in vasodilator stress MPI. These include left ventricular (LV) ejection fraction, LV wall motion score, LV volume, ST segment changes, lung-heart ratio, transient ischemic dilation, and heart rate response (HRR). …