© 2005 The European Society of Cardiology. Published by Elsevier Ltd. All rights reserved.
CP03: PERMANENT DIRECT HIS BUNDLE PACING DOESN'T INDUCE VENTRICULAR DYSSYNCHRONY AS OPPOSED TO CONVENTIONAL RIGHT VENTRICULAR APICAL DDD PACING
Cardiology Division – Ospedale S. Maria del Carmine – Rovereto (TN) – Italy
Beneficial effects of A-V synchrony due to DDD right ventricular apical (RVA) pacing could be neutralized by ventricular dyssynchrony(D).No data are reported about effects of direct his bundle pacing(DHP) on ventricular synchronism.
AIM: To assess the capability of DHP to prevent pacinginduced ventricular D as compared to DDD-RVA pacing in pts undergoing permanent DHP.
METHODS: 7 pts(2women,mean age 77+/–5)with normal HV were implanted for SSS(6 brady-tachy,1 LW II AVB) with a right atrium lead connected to the atrial channel of the device and a 4.1F screw-in hisian lead(Medtronic,Select Secure)connected to the ventricular channel.Two 4-polar leads through a femoral vein were used for DDD-RVA pacing. Fixation of permanent DHP lead was performed above the tricuspid valve using pacemapping and HB potentials. All pts underwent PW tissue Doppler imaging(TDI)analysis to assess inter- and intra-ventricular D. Interventricular mechanical delay(IVMD) between pulmonary and aortic systolic flow, septal to left posterior wall motion delay(SPWMD),and maximal difference between DTI systolic velocities of any 2 of the 4 left ventricle basal segments(maxmin DTI)were measured. DDD-RVA pacing was compared to DHP and to DHP+/–capture of right ventricular high inflow septum(RVHS)at the same atrial pacing rate after optimizing A-V interval.
RESULTS: Permanent DHP was safely obtained in 6 of 7 pts (only RVHS pacing in 1 pt). DHP and RVHS pacing thresholds, impedance and sensed potentials of DHP leads were 1.4+/–0.65 V and 1.7+/–0.8 V(x0.5 ms),611+/–162 ohm and 5.7+/–3.7mV respectively.In 5 of 6 pts DHP threshold was slightly inferior to RVHS capture threshold.Procedural and fluoroscopy times were 145 min (range 106-147) and 10.3+/–4.4 min respectively. Inter- and intra-ventricular D were reduced during DHP in comparison with DDD-RVA pacing: IVMD 198+/–36 ms vs 47+/–39 ms(cut-off value: 110; p<0.05); V-VD 45+/–18 vs 3+/–2.12 (cut-off value:30;p<0.05);max-min DTI 33.3+/–5.77 vs 19.2+/–12.5(cut-off value:10 ms).Similar data were obtained comparing DHP+RVHS and DDD-RVA pacing.No differences were observed between DHP and DHP+RVHS pacing.
CONCLUSION: DHP is feasible and safe. It prevents pacing-induced ventricular D as opposed to standard RVA DDD pacing. Longer follow-up is required to assess left ventricle remodelling prevention.