Noninvasive Identification of ATTRwt Cardiac Amyloid: The Re-emergence of Nuclear Cardiology.

More than half of all subjects with chronic heart failure are older adults with preserved ejection fraction (HFpEF). Effective therapy for this condition is yet to be delineated by clinical trials, suggesting that a greater understanding of underlying biologic mechanisms is needed, especially for the purpose of clinical intervention and future clinical trials. Amyloid infiltration of the myocardium is an underappreciated contributing factor to HFpEF that is often caused by misfolded monomers or oligomers of the protein transthyretin. While previously called senile cardiac amyloidosis and traditionally requiring endomyocardial biopsy for diagnosis, advances in our pathophysiologic understanding of this condition, coupled with nuclear imaging techniques using bone isotopes that can diagnose this condition noninvasively and the development of potential therapies, have resulted in a renewed interest in this previously considered "rare" condition. This reviewer focuses on the re-emergence of nuclear cardiology using pyrophosphate agents that hold promise for early, noninvasive identification of affected individuals.