Nuclear Cardiology in Congestion Heart Failure

Heart failure is increasing worldwide at epidemic proportions, resulting in considerable disability, mortality and increase in healthcare costs. Gated Single Photon Emission Computed Tomography - Myocardial Perfusion Imaging (GSPECT MPI) is the most prominent imaging modality capable of providing information on the global and regional ventricular function, the presence of intraventricular synchronism and myocardial perfusion and viability with the same test. Since most heart failure patients will undergo a GSPECT MPI study as part of the work-up, and the technique is widely available, these patients can benefit from the simple additional phase analysis to measure left ventricular dyssynchrony as a mean to better assess those who will be submitted to cardiac resynchronization therapy (CRT).  CRT is an important new treatment for symptoms associated with congestive heart failure (CHF) caused by the weakening of the heart muscle (cardiomyopathy). Cardiomyopathy is most commonly caused by irreversible damage from coronary artery disease (CAD), but may also be the result of genetic factors, viral infections, or toxins (such as alcohol).  Many patients with cardiomyopathy and CHF also have an abnormality of the heart’s electrical system resulting in an uncoordinated (asynchronous) contraction pattern of the heart muscle. This further reduces the pumping ability of a weakened heart muscle. The idea behind CRT is simple: Restoration of the normal coordinated pumping action of the ventricles; this is accomplished through a unique type of cardiac pacemaker. Unfortunately 20%–40% of patients submitted to this expensive and with morbidity-associated therapy do not show response. It is of critical importance to better evaluate, properly select the candidates and guide this therapy.  The present protocol is proposed with the overall objective of improving the outcomes of heart failure patients by properly predicting response to CRT therapy and help guide the optimal placement of the left ventricular lead by using nuclear medicine techniques.