Chapter 18: Radionuclide Imaging in Heart Failure

INTRODUCTION

Despite many advances in therapy, chronic heart failure remains a prevalent condition with a high mortality rate.¹ The successful treatment of heart failure patients requires establishing an accurate diagnosis, identifying potentially reversible etiologies, determining the optimal therapy, and reliable risk assessment for stratification of patients at high risk for worsening. Several of these aspects of heart failure care can be gainfully evaluated via radionuclide imaging. This chapter will review established applications of radionuclide imaging in heart failure.

The clinician has several goals when evaluating a heart failure patient. One potential work flow sequence for the evaluation of newly diagnosed heart failure is shown in Figure 18-1. Once a clinical diagnosis of the syndrome of heart failure is made, an initial step is often the determination of left ventricular (LV) systolic function. Approximately one-half of patients will have heart failure with preserved ejection fraction (HFpEF, EF ≥40%), while the remainder will have LV systolic dysfunction (heart failure with reduced ejection fraction HFrEF, EF <40%).² Radionuclide imaging methods including single-photon emission computed tomography (SPECT), radionuclide ventriculography (RVG), and positron emission tomography (PET) can all provide highly accurate and repeatable measures of LV systolic and diastolic function (Chapter 11). Despite being as prevalent as HFrRF, the treatment of HFpEF remains largely symptom based and empirical, with very little supportive data from clinical trials. For patients with systolic dysfunction, HFrEF, a critical next step is the determination of etiology. Etiology evaluation can include identifying specific and potentially remediable causes such as valvular disease, coronary artery disease (CAD), specific cardiomyopathies, and pericardial disease. When extensive CAD is found, testing for ischemia and viability is helpful to determine benefit from coronary revascularization. Radionuclide imaging has critical roles in the determination of heart failure etiology (see below), identifying patients for coronary revascularization (Chapter 21), and the evaluation for specific cardiomyopathies such as amyloidosis and sarcoidosis (Chapter 24). For patients with nonischemic cardiomyopathy (NICM), and those with persistent LV systolic dysfunction after specific intervention, a combination of guideline-directed medical therapy (GDMT), and device therapy in selected patients (implantable cardioverter defibrillator [ICD], and cardiac resynchronization therapy [CRT]), form the cornerstone of current recommendations. Evolving applications such as myocardial sympathetic neuronal function (Chapter 23) and dyssynchrony imaging (Chapter 11) may have relevance to the selection of patients for ICD and CRT. Furthermore, PET/CT imaging with F-18 fluorodeoxyglucose (FDG) has established utility in the challenging area of diagnosing device infections (Chapter 24). A minority of patients will receive advanced heart failure therapies, including left and right ventricular assist devices (LVAD and RVAD) and cardiac transplantation. In posttransplant patients, radionuclide imaging has important prognostic value, which may influence therapeutic options in patients with suspected allograft vasculopathy (see below).