RV Septal Versus Minimized RV Pacing in Sick Sinus Syndrome

Overview

Background: * Potential negative effects of pacing in the RV-apex are well documented * However, study results comparing septal / RVOT-pacing versus RV-apical pacing controversial. * The optimal pacing mode in SSS (DDDR versus AAIR) is unclear, as the DDD (R) mode with an AV delay ≤ 220 ms should be the preferred pacing mode, according to the DANPACE trial \[DANPACE, ESC 2010, Stockholm\]. Aim: \- to evaluate chronic effects of proven right ventricular septal compared to minimized right ventricular septal pacing in patients with SSS Inclusion criterion: -Pacemaker indication according to current guidelines: sick sinus syndrome (SSS) Exclusion criteria: * Life expectancy \< 2 years * Age \<18 years * Noncompliance with regard to participation in the study * Pregnancy * AV block ° 2 and higher * Permanent atrial fibrillation * Heart failure NYHA III and IV, reduced LV-EF \<40% * ICD indication * Acute coronary syndrome. PCI or CABG \<3 months * Heart transplant * Placement of septal RV electrode is not possible Study design: * Prospective, monocentric, randomized, double-blinded * Run-in phase: for weeks AAI \[R\]-DDD \[R\] * Randomization: two groups A) septal right ventricular chamber pacing: mode DDD \[R\] versus B) Reduction of unnecessary ventricular pacing: AAI \[R\]-DDD \[R\]. * FU: 6 and 12-months Primary endpoints: -LV ejection fraction and end-systolic LV volume after 12 months. Secondary endpoints: -LV end-diastolic volume, TAPSE, parameters of dyssynchrony (SPWMD, LV-PEP, IVMD), AF-burden, % ventricular pacing, CPX: peak oxygen consumption (peak VO2), VO2 AT, VO2/HR, VE/VCO2 slope; QoL scores (SF-36) after 12 months. Statistics/sample size estimation: In order to detect a difference in LVEF of 5% and for LV-ESV of 5 mL between the 2 groups after 12 months: * 90% power/alpha 5%: 84 patients per group * 80% power/alpha 5%: 63 patients per group * 10% for compensation of drop-outs / patients lost of follow-up. Two-sided 5% type 1 error Analysis intention-to-treat and based on the finally programmed pacing mode. Material * PG: market released dual chamber pacemakers with the ability to pace AAI(R) -DDD(R) * pacing leads: market-released standard active electrodes * RV electrode: septal verified under multi-level screening (RAO/LAO) and ECG (LBBB narrow \<150 ms / inferior axis)

Background: * Potential negative effects of pacing in the RV-apex are well documented * Asynchronous ventricular activation * reduction of systolic and diastolic LV function * Experimental data: histological changes * Asymmetric LV hypertrophy and thinning * However, study results comparing septal / RVOT-pacing versus RV-apical pacing controversial: * Acute versus chronic * Small number of cases, uncontrolled, unblinded, * Brief periods of observation in the cross-over design (3 months) * "RVOT" often summarizes different stimulation sites: high RVOT, lateral, septal. Actually only limited data with proven septal stimulation * No objective performance assessment (CPX) * Assessment of alternative stimulation site previously RVOT versus RV-apex, * ventricular pacing compared to ventricular pacing, then tested a potential harm to another * The question of the optimal pacing mode of patients with SSS (DDDR versus AAIR) appears to be open again. While in Germany, two-chamber systems with AAI \[R\] mode with ventricular back-up are used, should the DDD (R) mode with an AV delay ≤ 220 ms be the preferred pacing mode, according to the results of the DANPACE trial for patients with SSS \[DANPACE, ESC 2010, Stockholm\]. Aim: \- to evaluate chronic effects of proven right ventricular septal compared to minimized right ventricular septal pacing in patients with SSS Inclusion criterion: -Pacemaker indication according to current guidelines: sick sinus syndrome (SSS) Exclusion criteria: * Life expectancy \< 2 years * Age \<18 years * Noncompliance with regard to participation in the study * Pregnancy * AV block ° 2 and higher * Permanent atrial fibrillation * Heart failure NYHA III and IV, reduced LV-EF \<40% * ICD indication * Acute coronary syndrome. PCI or CABG \<3 months * Heart transplant * Placement of septal RV electrode is not possible Study design: * Prospective, monocentric, randomized, double-blinded * Run-in phase: 4 weeks AAI \[R\]-DDD \[R\] * ECG, PM-interrogation, echocardiography, performance diagnostics, CPX, QoL questionnaire * Randomization: two groups 4 weeks (between 3 to 6 weeks) after implant A) septal right ventricular chamber pacing: mode DDD \[R\] versus B) Reduction of unnecessary ventricular pacing: AAI \[R\]-DDD \[R\]. * FU: 6 and 12-months * ECG, Holter-ECG, PM-interrogation, echocardiography, performance diagnostics, CPX, QoL questionnaire * Extension of follow-up if possible Primary endpoints: -LV ejection fraction and end-systolic LV volume after 12 months. Secondary endpoints: -LV end-diastolic volume, TAPSE, parameters of dyssynchrony (SPWMD, LV-PEP, IVMD), AF-burden, % ventricular pacing, CPX: peak oxygen consumption (peak VO2), VO2 AT, VO2/HR, VE/VCO2 slope; QoL scores (SF-36) after 12 months. Blinding: * Patient compared to the pacing mode * Physician: offline analysis of echo and CPX blinded to the pacing mode Statistics/sample size estimation: In order to detect a difference in LVEF of 5% and for LV-ESV of 5 mL between the 2 groups after 12 months: * 90% power/alpha 5%: 84 patients per group * 80% power/alpha 5%: 63 patients per group * 10% for compensation of drop-outs / patients lost of follow-up. Two-sided 5% type 1 error Analysis intention-to-treat and based on the finally programmed pacing mode. Material * PG: market released dual chamber pacemakers with the ability to pace AAI(R) -DDD(R) * pacing leads: market-released standard active electrodes (eg. BSCI FineLine 4470 and 4471) Implantation * Transvenously * RA-electrode: if possible, short atrial conduction time * RV electrode: septal verified under multi-level screening (RAO/LAO) and ECG (LBBB narrow \<150 ms / inferior axis)