Use of 3-D Blood Pool Scintigraphy to Guide Left Ventricular Pacing Lead Placement in Patients Requiring Cardiac Resynchronization Therapy (MUGA CRT)

Use of 3-D Blood Pool Scintigraphy to Guide Left Ventricular Pacing Lead Placement in Patients Requiring Cardiac Resynchronization Therapy

Use of 3-D Blood Pool Scintigraphy to Guide Left Ventricular Pacing Lead Placement in Patients Requiring Cardiac Resynchronization Therapy (MUGA-CRT)

The purpose of this study is to determine whether multiple gated acquisition (MUGA) guided lead placement improves clinical outcomes for patients needing cardiac resynchronization therapy (CRT) compared to traditional posterolateral left ventricular lead placement.

Heart failure (HF) has a prevalence of five million individuals in the United States. Approximately 25-30% of patients with HF due to left ventricular (LV) systolic dysfunction have prolonged QRS. Prolonged QRS duration (>120ms) on ECG in HF patients is associated with increased morbidity and mortality. Delayed electrical activation of the LV translates to temporal delay in ventricular contraction. This is referred to as mechanical dyssynchrony. Patients with advanced HF, low ejection fraction (EF) of less than 35% and QRS of more than 120ms are indicated for cardiac resynchronization therapy (CRT). While most patients undergoing CRT implantation show dramatic improvement in HF symptoms, 30-40% of the HF patients undergoing CRT placement do not show a clinical response. The site of placement of the LV lead has been shown to be an important determinant of the effects of CRT. Measurement of left ventricular ejection fraction (LVEF) is performed using non-invasive measures such as the MUGA. By using the available information on left ventricular systolic function the investigators plan on investigating the effects of MUGA-guided versus traditional LV lead placement for CRT.

This test measures the distance that a patient can quickly walk on a flat, hard surface in a period of 6 minutes.

Minnesota Living with Heart Failure Questionnaire: To measure the effects of symptoms, functional limitations, psychological distress on an individual's quality of life, the MLHF questionnaire asks each person to indicate using a 6-point, zero to five, Likert scale how much each of 21 facets prevented them from living as they desired.

Echo is a type of ultrasound test that takes pictures of the heart. These pictures will be used to assess whether there are any improvements in left ventricular function.

Inclusion Criteria: Male or female, 18 years or older Must have an approved indication for CRT implantation Must have ischemic or nonischemic dilated cardiomyopathy Must have symptomatic HF with a New York Association (NYHA) Classification of III or IV Must be on optimal pharmacological therapy (this should include at the minimum, ACE inhibitor and beta-blocker therapy as tolerated. Must have left ventricular ejection fraction (LVEF) of ≤35% Must have ventricular conduction delay manifested as a QRS duration of >120msec Must be able to provide informed consent for study participation and be willing to comply with follow-up tests and scheduled visits Exclusion Criteria: HF diagnosis for less than 3 months Physical limitations to ambulation Life expectancy of less than six months Pregnant or planning for pregnancy in the next 6 months (must have a negative pregnancy test 7 days prior to enrollment)