Selection of patient for cardiac resynchronization therapy: role of QT corrected dispersion.

AIMS: About 30 to 50% of patients undergoing cardiac resynchronization therapy (CRT) may not show clinical or echocardiographic improvement, despite fulfilling guidelines recommendations for CRT. For this reason, we need a more accurate method to assess CRT eligibility. The aims of this study were to verify, on a 12-month follow-up, the usefulness of QT corrected dispersion (QTcD) in a patient's selection for CRT. METHODS: We stratified 53 patients who underwent CRT, into two groups based on the estimation of QTcD, that is, QTcD > 60 ms and QTcD ≤ 60 ms. In all patients were performed New York Heart Association (NYHA) class determination, six-minute walking test, QtcD, and QRS measurements, and complete echocardiographic assessment at 1, 3, 6, and 12 months after implantation. RESULTS: At baseline, there were no significant differences in clinical, echocardiographic, and electrocardiographic parameters duration between two groups. At 12-month follow-up between the two groups, there were significant differences in NYHA (1.2 ± 0.4 vs 2 ± 0.6; P < 0.01), six-minute walking distance (422 ± 68 vs 364 ± 68; P < 0.01), left ventricular (LV) ejection fraction (34 ± 7% vs 28 ± 6%; P < 0.01), LV end-diastolic diameter (57 ± 7 vs 63 ± 8; P < 0.01), and LV intraventricular dyssynchrony (24 ± 14 vs 39 ± 23; P < 0.01). CONCLUSION: This study suggests that QTc dispersion in addition to QRS duration could improve the sensitivity of electrocardiogram in a patient's selection for CRT.

Functional and clinical implications of cardiac resynchronization therapy on outcomes of diabetic patients with heart failure.

AIMS: To compare functional and structural changes of the left ventricle and long-term clinical outcomes in diabetic and nondiabetic patients with heart failure undergoing cardiac resynchronization therapy (CRT). METHODS: Sixty-eight patients with heart failure undergoing CRT were included: 18 were diabetic patients and 50 nondiabetic patients. The CRT eligibility was established by echocardiographic assessments. RESULTS: CRT improved ventricular geometry and dyssynchrony in both diabetic and nondiabetic patients, with no significant difference in the magnitude of the effects on the left ventricular function. Over a median follow-up of 30.6 ± 6.2 months, there were no significant differences in the rates of any cause death (16.7 vs. 14.0%, P = 0.72), cardiac death (11.1 vs. 8.0%, P = 0.65) and heart rehospitalization (5.6 vs. 6.0%, P = 1.0), between diabetic and nondiabetic patients, respectively. Diabetes was not found to be an independent factor associated with worse clinical outcome. CONCLUSION: Resynchronization therapy provided significant functional and hemodynamic improvements in both diabetic and nondiabetic patients. Long-term prognosis in heart failure patients with diabetes was comparable with that in those without diabetes.