This study was designed to examine the importance of the underlying cardiac pathology on outcome of cardiac resynchronization therapy (CRT), hypothesizing that myocardial infarction scar and other noncontractile segments represent limitations to the ability to resynchronize cardiac contraction in patients with congestive heart failure associated with dilated cardiomyopathy. From October 1999 to April 2002, 158 patients (mean age 65 years, 121 men) were included in a single center, longitudinal, comparative study. All patients had dilated cardiomyopathy and indications for CRT with a mean QRS duration of 174 ms. The patient population was divided into a coronary artery disease (CAD) group that included patients with significant CAD, and no indication, or a contraindication for revascularization, and a non-CAD group that included patients with nonischemic dilated cardiomypopathy. Follow-up data were collected at 3, 6, and 12 months, and yearly thereafter. The median follow-up was 11.2 months. In the CAD group, the LVEF increased from 0.29 to 0.34 (P < 0.0001), the 6-minute walk test distance increased from 310 to 463 m (P < 0.0001), and the percentage of patients in NYHA functional Class III-IV decreased from 83% to 23% (P = 0.04). In the non-CAD group, LVEF increased from 29% to 42% (P < 0.0001), the 6-minute walk test distance increased from 332 to 471 m (P < 0.0001), and the percentage of patients in NYHA functional Class III-IV decreased from 79% to 5%, (P < 0.0001). Comparison of the two groups showed that patients in the non-CAD group had a significantly greater increase in LVEF (P = 0.007) and decrease in NYHA class (P < 0.05). Patients with CAD or non-CAD significantly improved clinically during CRT. Non-CAD patients had a greater increase in LVEF and decrease in NYHA functional class than patients with CAD.
Short-term hemodynamic studies consistently report greater effects of cardiac resynchronization therapy (CRT) in patients stimulated from a LV lateral coronary sinus tributary (CST) compared to a septal site. The aim of the study was to compare the long-term efficacy of CRT when performed from different LV stimulation sites. From October 1999 to April 2002, 158 patients (mean age 65 years, mean LVEF 0.29, mean QRS width 174 ms) underwent successful CRT, from the anterior (A) CST in 21 patients, the anterolateral (AL) CST in 37 patients, the lateral (L) CST in 57 patients, the posterolateral (PL) CST in 40 patients, and the middle cardiac vein (MCV) CST in 3 patients. NYHA functional class, 6-minute walk test, and echocardiographic measurements were examined at baseline, and at 3, 6, and 12 months. Comparisons were made among all pacing sites or between lateral and septal sites by grouping AL + L + PL CST as lateral site (134 patients, 85%) and A + MC CST as septal site (24 patients, 15%). In patients stimulated from lateral sites, LVEF increased from 0.30 to 0.39 (P < 0.0001), 6-minute walk test from 323 to 458 m (P < 0.0001), and the proportion of NYHA Class III-IV patients decreased from 82% to 10% (P < 0.0001). In patients stimulated from septal sites, LVEF increased from 0.28 to 0.41 (P < 0.0001), 6-minute walk test from 314 to 494 m (P < 0.0001), and the proportion of NYHA Class III-IV patients decreased from 75% to 23% (P < 0.0001). A significant improvement in cardiac function and increase in exercise capacity were observed over time regardless of the LV stimulation sites, either considered singly or grouped as lateral versus septal sites.
Normal resting wall motion at echocardiography coupled to normal stress myocardial perfusion, rules out the presence of significant coronary allograft vasculopathy in many heart transplant recipients. Conversely, resting wall motion abnormalities and perfusion defects strongly predict cardiac events. Therefore, a strategy which reserves angiography for patients with resting wall motion abnormalities and/or perfusion defects may be safe and cost-effective.
Insulin-treated diabetes is associated with a worse functional recovery and a higher mortality in patients with advanced heart failure after CRT. While cardiac death accounts for the majority of deaths in nondiabetic patients, a relevant proportion of the mortality in diabetic patients seem to result from noncardiac causes.
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