Abstract 12569: Intrathoracic Impedance Change Reflects Reverse Left Ventricular Remodeling in Response to Cardiac Resynchronization Therapy in Chronic Heart Failure
Background: Intrathoracic impedance monitoring has been reported to be useful for prediction of worsening chronic heart failure. However, it is not revealed the relation between changes in intrathoracic impedance and improvement of cardiac function in chronic heart failure patients with cardiac resynchronization therapy (CRT) implantation. Therefore, we investigated whether intrathoracic impedance change reflects reverse left ventricular (LV) remodeling in response to CRT in patients with chronic heart failure.
Methods: The study subjects consisted of 25 chronic heart failure patients (18 males, mean age 66±11 years) with CRT-defibrillator (CRT-D) implantation. The patients were divided into two groups based on whether intrathoracic impedance fluid index reached over 60 ohms (group A, n=6) or not (group B, n=19) within 6 months observation after CRT-D implantation. Levels of plasma BNP, serum total bilirubin, LV end-diastolic volume (LVEDV), LV end-systolic volume (LVESV) and LV ejection fraction (LVEF) were measured before and 6 months after CRT-D implantation. The numbers of patients with ventricular arrhythmias requiring appropriate shock therapy were examined during 6 months in each group.
Results: In group B, BNP (595±106 pg/ml vs. 332±91 pg/ml, P<0.05), total bilirubin (1.2±0.2 mg/dl vs. 0.8±0.1 mg/dl, P<0.05), LVEDV (191±16 ml vs. 149±13 ml, P<0.05) and LVESV (140±12 ml vs. 102±11 ml, P<0.05) were significantly decreased 6 months after CRT-D implantation. LVEF (28±2% vs. 33±2%, P<0.05) was significantly increased after CRT-D implantation. On the other hand, no significant changes were detected in any parameters in group A. The numbers of patients with ventricular arrhythmias requiring appropriate shock therapy were not different between 2 groups (1 (17%) in group A vs. 2 (10%) in group B, NS).
Conclusion: These data suggested that intrathoracic impedance change reflects reverse left ventricular remodeling in response to CRT in patients with chronic heart failure. Therefore, the monitoring of changes in intrathoracic impedance is useful for predicting CRT responder in chronic heart failure patients.
- © 2010 by American Heart Association, Inc.