ABSTRACT
AIMS: To evaluate the clinical implication of right ventricular (RV) to left ventricular (LV) interlead sensed electrical delay (RV-LVs) and the relation to ventricular lead position in cardiac resynchronization therapy (CRT). METHODS AND RESULTS: Eighty-five consecutive CRT patients (mean age 66 ± 11 years) received LV lead prospectively targeted to the latest mechanical activated segment (concordant), assessed by two-dimensional speckle tracking radial strain (ST-RS) echocardiography. The RV lead was randomized to RV apex (n= 43) or RV high posterior septum (n= 42). Right ventricular to left ventricular interlead sensed electrical delay was obtained during the CRT implant procedure. Intraventricular dyssynchrony was evaluated by ST-RS echocardiography. Interventricular mechanical delay (IVMD) was measured by using pulse-wave Doppler. Separated by the median RV-LVs (82 ms), a long RV-LVs demonstrated more LV end-systolic volume (LVESV) reduction than a short RV-LVs (-27 ± 20 vs. -16 ± 22%; P= 0.02), 6 months after CRT (6FU). Right ventricular to left ventricular interlead sensed electrical delay correlated to IVMD (r = 0.50; P< 0.001) and intraventricular dyssynchrony (r = 0.25; P= 0.02) at baseline. Concordant LV leads (n= 61) demonstrated superior reduction of LVESV (P= 0.005) 6 months after CRT; however, both RV lead positions had similar effects. Right ventricular to left ventricular interlead sensed electrical delay was irrespective to LV lead concordance and RV lead position (P= ns). Independent predictors to reverse remodelling (reduction of LVESV ≥ 15%) at 6FU were concordant LV lead (odds ratio, 3.210; P= 0.029) and IVMD (odds ratio, 1.028; P= 0.026). CONCLUSION: Right ventricular to left ventricular interlead sensed electrical delay was not predictive to LV reverse remodelling affected by CRT at 6FU. Concordant LV leads demonstrated superior LV reverse remodelling at 6FU. Right ventricular to left ventricular interlead sensed electrical delay was irrespective of ventricular lead position and might be insufficient to target optimal LV lead position in CRT. TRIAL REGISTRATION: http://clinicaltrials.gov. Unique identifier: NCT01035489.
Subject(s)
Cardiac Resynchronization Therapy/methods , Electroencephalography/methods , Heart Failure/diagnosis , Heart Failure/prevention & control , Ventricular Dysfunction, Left/diagnosis , Ventricular Dysfunction, Left/prevention & control , Ventricular Dysfunction, Right/diagnosis , Aged , Electrodes, Implanted , Female , Heart Failure/complications , Humans , Male , Prosthesis Implantation/methods , Reproducibility of Results , Sensitivity and Specificity , Treatment Outcome , Ventricular Dysfunction, Left/etiology , Ventricular Dysfunction, Right/etiology , Ventricular Dysfunction, Right/prevention & controlABSTRACT
BACKGROUND: Cardiac resynchronization therapy (CRT) is an established method for treatment of patients with severe congestive heart failure and asynchronous left ventricular contraction. Its clinical and haemodynamic benefits are well documented. We have retrospectively reviewed CRT performed at our centre. MATERIAL AND METHODS: Our department treated 150 patients with CRT according to accepted indications from 1999-2006. The patients were observed for two years and one third reached two-year follow-up. We reviewed operative complications, lead re-implantations, clinical benefits, pacing thresholds, electrogram amplitudes and lead impedance.. RESULTS: There were 20% lead re-implantations after two years of follow-up and a significant improvement in NYHA functional capacity. For the coronary venous lead the average stimulation threshold was stable at 1.2-1.3 V at 0.5 ms, the sensing electrogram amplitude was 10-18 mV and the impedance was 600 ohm at 5.0 V during follow-up. Similar stable electrophysiological values were measured for the right ventricular lead and the atrial lead. INTERPRETATION: There were in general few peroperative complications. All implanted leads in CRT showed stable- and low threshold values during a two-year follow-up period.
