SAN DIEGO -- With PET-guided lead placement, cardiac resynchronization therapy (CRT) can achieve significant clinical improvement in patients with severe ischemic heart failure, even in the presence of extensive scarring, investigators reported here.
SAN DIEGO, Sept. 17 -- With PET-guided lead placement, cardiac resynchronization therapy (CRT) can achieve significant clinical improvement in patients with severe ischemic heart failure, even in the presence of extensive scarring, investigators reported here.
Two-thirds of patients responded to therapy, despite evidence that CRT works only in patients with nonischemic heart failure, Lucie Riedlbauchova, M.D., of the Institute for Clinical and Experimental Medicine in Prague, Czech Republic, reported at the American Society of Nuclear Cardiology meeting.
Responders also lived significantly longer than nonresponders did, Dr. Riedlbauchova said.
"Our results show that CRT-associated reverse remodeling can be expected even in patients with extensive left ventricular scarring," said Dr. Riedlbauchova. "Using PET to place CRT leads remotely from the scar is associated with a more sizeable treatment effect."
The study involved 66 CRT patients with documented stenosis of 60% or more in at least one coronary artery (or a history of myocardial infarction). All the patients had PET exams that included both rubidium-82 perfusion imaging and 18F-FDG viability assessment prior to CRT implantation. No patient had a revascularization procedure after PET imaging and initiation of CRT.
CRT response was defined as:
The study had a mean follow-up of 18.5 months and a median of 16.0 months.
Dr. Riedlbauchova reported that lead placement and pacing remotely from scar area led to significant improvement in NYHA classification and to reverse remodeling. Myocardial hibernation or ischemia at the site of pacing did not affect the therapeutic impact of CRT.
The nonresponse rate was 35%, despite the presence of extensive left ventricular scarring in the patient population. Scar burden and the number of viable or scar segments had limited predictive value for discriminating responders from nonresponders, said Dr. Riedlbauchova.
Twenty patients died during follow-up, 14 of whom were nonresponders. Among the patients who died, the time from CRT implantation to death was significantly longer in patients who'd responded to resynchronization therapy (34 months versus 9 months in nonresponders, P=0.01) and in patients who had scarring that involved less than 25% of the left ventricle (P=0.01 versus more extensive scarring).
"We could identify no predictors of both responsivity and mortality," said Dr. Riedlbauchova.