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Acute effects of RV pacing on cardiac hemodynamics and transvalvular impedance. M .Ta borsky, M.Fedorco, T.Skala, E.Kocianova, D.Richter, D.Marek, J.Ostransky Dept. of Internal Medicine - Cardiology, University Hospital, Olomouc, Czech Republic.
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Acute effects of RV pacingon cardiac hemodynamicsand transvalvular impedance M.Taborsky, M.Fedorco, T.Skala, E.Kocianova, D.Richter, D.Marek, J.Ostransky Dept. of Internal Medicine - Cardiology, University Hospital, Olomouc, Czech Republic
Chronic right-ventricular apical pacing can affect the cardiac function • Electrical and mechanical desynchronization • Reduced myocardial performancewith increased stress • Increased risk of AF and CHF
Open questions • Does right-ventricular pacing (RVP) also produce acute effects on cardiac hemodynamics ? • Can the RVP long-term consequences be predicted from the acute effects ? • What are the most sensitive indicatorsof pacing-induced hemodynamic troubles ? • Is the hemodynamic impact of RVP dependent on the pacing site ? • Can the risk be reduced by individual pacing site selection ?
Study design • During dual-chamber implantation procedures for SSS or AVB, the ventricular lead was sequentially positioned in RV apex and mid-septum. Measurements: • left-ventricular pressure and dP/dt; • systolic and diastolic hemodynamic parameters assessed by 2D echocardiography and by echo and tissue Doppler; • Transvalvular impedance (TVI). Recording conditions: • intrinsic activity; AAI pacing at 90 bpm; • VDD and DDD pacing at 90 bpm with apical and septal stimulation.
AEGM VEGM ECG I LVP 150 mmHg dP/dt 2000 mmHg/s TVI (Vring) 50 Ohm Set of tracings
Paired Student t-test (n=29) The increase in QRS duration induced by ventricular pacingdepends on the pacing site
The increase in QRS duration induced by ventricular pacingdepends on the pacing site Paired Student t-test (n=29)
AEGM VEGM 2:1 AVB QRS 110 ms ECG II LVP VDD in RVA QRS 180 ms VDD in RVS QRS 120 ms RV septal stimulation improves QRS axis and duration with respect to apical pacing
ECG I LVP dP/dt VDD; 80 ms AV delay IAVC dP/dtmax is reduced by RV pacing at either site
Was there individual preference for a specific pacing site? y = x Septal pacing was better Apical pacing was better
ECG II LVP dP/dt IAVC VDD; 80 ms AV delay LVP decrease is affected
LVP sys is not modified by VDD pacing LVP dias is significantly increased
Rate increase to 90 bpm produced by: • AAI pacing • DDD pacing (80 ms AV delay) in RV apex • DDD pacing (80 ms AV delay) in mid-septum
Effects of cardiac rate on dP/dtmax and LVP sys
Effects of RV pacing on echocardiographic systolic parameters
TVI 60 Ohm VEGM AAI 60 bpm AEGM ECG II LVP 100 mmHg TVI DDD 60 bpm RV lead in mid septum In some cases, RV pacing induced virtually no change in TVI waveform
AEGM Sinus rhythm VEGM ECG I ESTVI 460 Ohm TVI EDTVI 421 Ohm VDD ESTVI 461 Ohm TVI EDTVI 434 Ohm RV lead in mid septum In some cases, RV pacing affected TVI amplitude
AEGM VEGM I LVP TVI 60 Ohm transition from AAI to VDD RV lead in apex In other cases, RV pacing induced morphological changes in TVI
TVI was measured in both RV apex and septum in 32 patients. The success frequency was not significantly different at the two recording sites. TVI recording can be performed in RV septum as well as in apex
Right ventricular pacing affects TVI properties The frequency of substantial morphological alterations was much higher in RV apex than septum
OK = no morphological alteration OK = no morphological alteration and amplitude 75% With intrinsic rhythm, the TVI signal was appropriate at both RV apex and septum in 25 cases. The frequency of cases featuring unaltered TVI waveform with VDD pacing was significantly higher in RV septum than apex.
OK = no morphological alteration OK = no morphological alteration and amplitude 75% DDD was tested in 18 cases featuring appropriate TVI at both RV apex and septum with intrinsic rhythm. The frequency of cases with unaltered TVI waveform in 90 bpmDDD was significantly higher in RV septum than apex.
CONCLUSIONS • Right ventricular pacing applied in apex or mid-septum acutely affected both systolic and diastolic function. • The QRS duration was longer and the proportion of cases featuring deep alterations in TVI waveform was higher with apical than septal pacing. • Left ventricular pressure and echocardiographic parameters were similarly affected by RV pacing applied at either site. • Septal stimulation might produce a shorter electrical interventricular delay and milder mechanical modifications in RV with respect to apical pacing,while LV hemodynamic indices dependent on the intraventricular synchronization seem to be less sensitive to the position of the pacing lead.