Hemodynamic Effects Of Biventricular Pacing Research Articles

Mechanical and hemodynamic effects of left bundle branch area versus biventricular pacing in virtual heart failure patients with left bundle branch block

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The Dutch Research Council (NWO) Background Left bundle branch area pacing (LBBAP) has been introduced as an alternative, more physiological pacing strategy to biventricular pacing (BiVP). LBBAP can result in selective LBB pacing (sLBBP), non-selective LBB pacing (nsLBBP), or LV septal pacing (LVSP). Direct comparison between the different pacing strategies is challenging due to the practical implications of performing multiple pacing procedures within the same patients, as well as the large heterogeneity of underlying disease in patients. Computational models can be used to perform controlled in silico experiments and to compare all possible pacing modalities under the same conditions. Aim To investigate the effects of LBBAP strategies versus BiVP on cardiac mechanics and hemodynamics in a set of well-defined virtual heart failure patients. Methods An electrophysiological model was used to calculate biventricular electrical activation maps during LBBB and the different pacing strategies. The resulting regional activation times were imposed to the well-validated CircAdapt model of the human four-chamber heart and circulation. A set of virtual patients at different stages of heart failure are then defined within the CircAdapt framework, which is achieved by decreasing the contractility of the LV myocardium, such that LVEF≤35%. The CircAdapt model is then used to compute regional ventricular strain patterns and myocardial work as well as global ventricular pump function during LBBB, BiVP and the different LBBAP modalities. Results Selective LBBP is best at restoring mechanical homogeneity in LV contraction as evidenced by simulated wall strains waveforms (Fig 1, Left). NsLBBP increases septal dyssynchrony and introduces small pre-stretch in the LVfw (1.3±0.3%). This effect is more pronounced in LVSP (2.4±1.4%). In BiVP, pre-stretch occurs only in a single LV free wall (LVfw) segment, but all septal segments display a distinct oscillatory pattern. Work load homogeneity (Fig 1, Center) was best restored in sLBBP (4.9±1.1 kPa). NsLBBP lead to reduced homogeneity (4.9±1.8 kPa). LVSP reduced this further (4.8±2.6kPa), while BiVP performed similarly (4.6±2.6kPa) to LVSP. All modalities vastly improved on the baseline LBBB (4.06±5.6 kPa). Hemodynamically (Fig 1, Right), sLBBP showed greatest improvement in LV function (LVESV:-8.1%; LVEF:+6.8%; MLAP:-16.4%; LVdp/dtmax:+12.8%), followed by nsLBBP (LVESV:-7.2%; LVEF:+6.0%; MLAP:-14.5%; LVdp/dtmax:+12.5%), LVSP (LVESV:-5.6%; LVEF:+4.6%; MLAP:-11.7%; LVdp/dtmax:+12.358%) and finally BiVP (LVESV: -4.6%; LVEF:+3.8%; MLAP:-9.3%; LVdp/dtmax:+9.8%) Conclusion We were able to simulate LBBB and subsequent pacing strategies in virtual heart failure patients. This approach allowed direct comparison of mechanical and hemodynamic effects of BiVP and LBBAP modalities without confounding variables. Our results indicate that all LBBAP modalities perform at least similar to bi-ventricular pacing regardless of mechanical viability.

Acute hemodynamic effects of biventricular pacing studied during cardiovascular magnetic resonance imaging: the PICARIA Trial

Abstract Background Cardiac resynchronization therapy (CRT) is hampered by a relative high rate of non-response whereby device optimization could aid in improving benefit from CRT. Nonetheless, a non-invasive and reproducible clinical tool for device optimization is currently lacking. Recently introduced cardiovascular magnetic resonance (CMR) compatible CRT devices may allow for patient follow-up and device optimization as biventricular (BIV) pacing can be performed during the CMR exam. However, to date, CMR evaluation of acute pump function changes during CRT is limited. Purpose To assess the effects of BIV-pacing on change in left ventricular (LV) function and contraction patterns using CMR. Methods Ten patients were included in this prospective pilot study. All patients underwent CMR imaging (1.5T system) prior to device implantation (baseline), and 6 weeks after device implantation (CRT-on and CRT-off). LV end systolic volume (ESV), end diastolic volume (EDV), ejection fraction (LVEF), and measures of LV dyssynchrony and dyscoordination (septal systolic rebound stretch (SRSseptal)) were assessed on cine images. Results LV function and contraction patterns before and after device implantation are compared and displayed in the figure. LV ESV and EDV decreased in all patients during BIV-pacing as compared to intrinsic rhythm (CRT-off) (ESV; 161.4±36.3ml vs. 194.9±37.1ml, p<0.01 and EDV; 236.2±31.8ml vs. 268.1±42.3ml, p<0.01). A significant improvement in LVEF was observed during BIV-pacing (32.2±8.7% vs. 27.4±5.9%, p<0.01). Both, regional dyssynchrony and regional dyscoordination significantly improved during CRT-on compared to CRT-off (peakseptal-peaklateral; 57±46ms vs. 183±86ms, p<0.01 and SRSseptal; 2.1±2.6% vs. 6.0±3.0%, p<0.01). Conclusions Post-CRT implantation CMR assessing acute pump function changes to different CRT pacing settings is feasible and provides important insights in the effects of BIV-pacing on cardiac function and contraction patterns. LV assessment using CMR, potentially in combination with non-invasive pressure measurements, may constitute a future CRT optimization strategy. Funding Acknowledgement Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Biotronik (Berlin, Germany)

Abstract 12785: In Patients Supported by a Left Ventricular Assist Device, Bi-Ventricular Pacing does not Offer Hemodynamic Improvement over Right Ventricular Pacing

Hypothesis: The benefit of biventricular (BiV) pacing in patients supported by a left ventricular assist device (LVAD) is unknown. This pilot study aimed to assess the acute hemodynamic effects of biventricular pacing compared to right ventricular (RV) pacing in patients supported by LVADs and to determine appropriate pacing rate. Methods: We studied 7 patients (age 65±7, 100% males) supported by Heartmate II (HM2) LVAD who underwent biventricular (BiV) pacemaker (PM) implant prior to LVAD. All patients underwent a ramp echo study for speed optimization prior to enrollment. Two patients were in sinus rhythm and 5 were in chronic atrial fibrillation (AF) and pacemaker dependent due to complete atrioventricular block (AVB). Results: A total of 42 complete sets of hemodynamics were obtained during BiV and RV pacing at various pacing rates ranging from 50 to 110 bpm. There were no significant differences in right atrial(RA) pressure, mean pulmonary artery(mPA) pressure, cardiac index(CI), PA saturation(PASat) and right ventricular stroke work index(RVSWI) between BiV and RV pacing (table). There was a trend for higher stroke volume index (SVI) and RVSWI at lower heart rates for each individual patient. Conclusion: BiV pacing does not appear to have any acute hemodynamic benefit compared to RV pacing in patients supported by HM2-LVAD. At lower heart rate, whether BiV or RV, may confer better RV efficiency.

A Clinical Phenotype of Adverse Response to Biventricular Pacing: A Case Series

Biventricular pacing is an established therapy for patients with heart failure with reduced left ventricular ejection fraction and prolonged QRS duration. However, there are few reports on the adverse effects of biventricular pacing. Three patients who deteriorated rapidly following biventricular pacing (heart transplantation/ventricular assist device within 3 months of device implantation) were identified. The clinical, echocardiographic, and functional characteristics before and after device implantation were evaluated. The acute hemodynamic effects of biventricular pacing were assessed by cardiac catheterization. Preimplant assessment showed biventricular dysfunction, pulmonary hypertension, and relatively narrow QRS duration. The time from device implantation to assessment was 62, 58, and 42 days. All three patients developed right bundle branch block (RBBB)-type QRS morphology, deterioration in right ventricular (RV) function, and functional capacity in association with rapid clinical decline. Acutely, biventricular pacing resulted in higher right atrial pressure, pulmonary wedge pressure, lower cardiac output, and RV stroke work in all three patients. A phenotype of adverse response to biventricular pacing is characterized by relatively narrow QRS duration, RV dysfunction, and pulmonary hypertension. Clinical decline is rapid and associated with the development of RBBB-type morphology, worsening of pulmonary hemodynamics, and RV dysfunction with biventricular pacing.

Acute and Chronic Hemodynamic Effects of Biventricular Pacing in Patients with Coronary Artery Disease and Lateral LV Wall Infarct

Acute and Chronic Hemodynamic Effects of Biventricular Pacing in Patients with Coronary Artery Disease and Lateral LV Wall Infarct

Tailored echocardiographic interventricular delay programming further optimizes left ventricular performance after cardiac resynchronization therapy

The aim of cardiac resynchronization therapy is correction of left ventricular (LV) dyssynchrony. However, little is known about the optimal timing of LV and right ventricular (RV) stimulation. The purpose of this study was to evaluate the acute hemodynamic effects of biventricular pacing, using a range of interventricular delays in patients with advanced heart failure. Twenty patients with dilated ischemic (n = 12) and idiopathic (n = 8) cardiomyopathy (age 66 +/- 6 years, New York Heart Association class III-IV, LV end-diastolic diameter >55 mm, ejection fraction 22% +/- 18%, and QRS 200 +/- 32 ms) were implanted with a biventricular resynchronization device with sequential RV and LV timing (VV) capabilities. Tissue Doppler echocardiographic parameters were measured during sinus rhythm before implantation and following an optimal AV interval with both simultaneous and sequential biventricular pacing. The interventricular interval was modified by advancing the LV stimulus (LV first) or RV stimulus (RV first) up to 60 ms. For each stimulation protocol, standard echocardiographic Doppler and tissue Doppler imaging (TDI) echo were used to measure the LV outflow tract velocity-time integral, LV filling time, intraventricular delay, and interventricular delay. The highest velocity-time integral was found in 12 patients with LV first stimulation, 5 patients with RV first stimulation, and 3 patients with simultaneous biventricular activation. Compared with simultaneous biventricular pacing, the optimized sequential biventricular pacing significantly increased the velocity-time integral (P <.001) and LV filling time (P = .001) and decreased interventricular delay (P = .013) and intraventricular delay (P = .010). The optimal VV interval could not be predicted by any clinical nor echocardiographic parameter. At 6-month follow-up, the incidence of nonresponders was 10%. Optimal timing of the interventricular interval results in prolongation of the LV filling time, reduction of interventricular asynchrony, and an increase in stroke volume. In patients with advanced heart failure undergoing cardiac resynchronization therapy, LV hemodynamics may be further improved by optimizing LV-RV delay.