Pacing In Heart Failure Patients Research Articles

Benefits of upgrading right ventricular to biventricular pacing in heart failure patients with atrial fibrillation.

Recommendations on cardiac resynchronization therapy (CRT) in patients with atrial fibrillation or flutter (AF) are based on less robust evidence than those in sinus rhythm (SR). We aimed to assess the efficacy of CRT upgrade in the BUDAPEST-CRT Upgrade trial population by their baseline rhythm. Heart failure patients with reduced ejection fraction (HFrEF) and previously implanted pacemaker (PM) or implantable cardioverter defibrillator (ICD) and ≥20% right ventricular (RV) pacing burden were randomized to CRT with defibrillator (CRT-D) upgrade (n = 215) or ICD (n = 145). Primary [HF hospitalization (HFH), all-cause mortality, or <15% reduction of left ventricular end-systolic volume] and secondary outcomes were investigated. At enrolment, 131 (36%) patients had AF, who had an increased risk for HFH as compared with those with SR [adjusted hazard ratio (aHR) 2.99; 95% confidence interval (CI) 1.26-7.13; P = 0.013]. The effect of CRT-D upgrade was similar in patients with AF as in those with SR [AF adjusted odds ratio (aOR) 0.06; 95% CI 0.02-0.17; P < 0.001; SR aOR 0.13; 95% CI 0.07-0.27; P < 0.001; interaction P = 0.29] during the mean follow-up time of 12.4 months. Also, it decreased the risk of HFH or all-cause mortality (aHR 0.33; 95% CI 0.16-0.70; P = 0.003; interaction P = 0.17) and improved the echocardiographic response (left ventricular end-diastolic volume difference -49.21 mL; 95% CI -69.10 to -29.32; P < 0.001; interaction P = 0.21). In HFrEF patients with AF and PM/ICD with high RV pacing burden, CRT-D upgrade decreased the risk of HFH and improved reverse remodelling when compared with ICD, similar to that seen in patients in SR.

Assessment of left ventricular activation conduction during left bundle branch area pacing in heart failure patients: A novel criterion to determine left bundle branch capture

Assessment of left ventricular activation conduction during left bundle branch area pacing in heart failure patients: A novel criterion to determine left bundle branch capture

Both LBBP and LVSP significantly improve ventricular dyssynchrony and effectivity of LV performance compared to RV apical pacing in heart failure patients with LBBB and an indication to CRT

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Supported by the Ministry of Health of the Czech Republic, grant number NU21-02-00584 and by the project National Institute for Research of Metabolic and Cardiovascular Diseases (Programme EXCELES, ID Project No. LX22NPO5104) - Funded by the European Union – Next Generation EU. Background Left bundle branch pacing and left septal myocardial pacing (LVSP) are novel methods of CRT in patients with heart failure. However, their exact impact on ventricular synchrony visualized by noninvasive assessment and the LV performance effectivity is unknown. Aims To compare ventricular synchrony and a change in blood pressure values between nonselective left bundle branch pacing (nsLBBP), LVSP, and RV apical pacing (RVAP) in heart failure patients. Methods In patients with CRT indication and LBBB, a lead was placed in the left septal area, where the transition between nsLBBP and LVSP was observed during decremental output pacing. Another lead was placed in the RV apex. UHF-ECG was used to assess ventricular synchrony during RVAP, nsLBBP, and LVSP. Dyssynchrony parameter e-DYS was calculated as an absolute value of the time difference between the first and last activation. Systolic blood pressure measurements were obtained invasively from the radial artery during VVI pacing at rates ten beats/minute higher than spontaneous rhythm. The protocol included multiple transitions between RVAP, nsLBBP, and LVSP. Results The study protocol was finalized in six patients; mean age 67 years, LVEF 33%, 3 had ischemic cardiomyopathy, and QRSd during spontaneous LBBB was 172±8 ms. QRSd was prolonged to 182±10ms during RVAP and shortened to 145±12 ms and 149±13 ms during nsLBBP and LVSP, respectively. The dyssynchrony parameter e-DYS shortened from 46±18 ms during RVAP to 1±16 ms during nsLBBP and 12±13 ms during LVSP, p &amp;lt; 0.05 for RVAP vs. nsLBBP and LVSP, and p = 0.4 for nsLBBP vs. LVSP. Both nsLBBP and LVSP led to a significant increase in the systolic blood pressure compared to RVAP (9±1 mmHg and 10±1 mmHg for nsLBBp and LVSP vs. RVAP, p &amp;lt; 0.001, respectively. nsLBBP produced slightly higher systolic blood pressure than LVSP (mean difference 2±1 mmHg, p = 0.005. Conclusion In patients with LBBB and CRT indication, both nsLBBp and LVSP significantly reduce ventricular dyssynchrony and lead to better effectivity of the LV performance compared to RV apical pacing.

Biventricular or left univentricular pacing in heart failure patients: is there a better strategy

Abstract Background Cardiac resynchronization therapy (CRT) is a cornerstone in treatment of heart failure (HF) with reduced left ventricular ejection fraction (LVEF) and ventricular dyssynchrony. Biventricular (BiV) pacing is often the preferred method and corrects electrical and mechanical dyssynchrony but Left ventricular (LV) preferential pacing is may preserve conduction via the right bundle branch, preventing deleterious effects from right ventricular. The evidence is sparse and there is doubts whether which programming strategy is better. Purpose We hypothesized that BiV is non-inferior to preferential LV pacing in HF patients with reduced LVEF and CRT devices in cardiovascular death and HF hospitalizations. Methods We retrospectively evaluated 147 patients with HF patients with reduced LVEF and CRT devices. Two groups were defined: LV pacing (group 1) and BiV pacing (group 2). Primary outcome was defined as cardiovascular death and secondary outcome as HF hospitalizations and NYHA class after CRT. Results Mean age was 70,26±10,6 years, 68,1% were males and follow-up was 52,22±44,51 months. One hundred and twenty six (85,7%) patients had implantable cardiac resynchronization therapy (CRT) defibrillator (CRT-D) and 21 (14,3%) CRT pacemaker (CRT-P). Mean LVEF was 31,1±8,5% and mean QRS duration before CRT implantation was 149,5±48,6 ms. Thirty-nine (36,4%) patients were in NYHA III–IV. HF aetiology was idiopathic in 51 (47,2%), ischemic in 36 (33,3%) and alcoholic cardiomyopathy in 9 (8,3%). Forty-five (40,5%) patients had atrial fibrillation and 37 (35,6%) coronary disease. Patients in group 2 were more frequently males than group 1 patients (46 (78,0%) vs 32 (56,1%) respectively, p=0,012). There were no differences in regard to age, LVEF, HF aetiology or other comorbidities between groups. In 57 (49,1%) CRT was programming in preferential LV pacing and 50 (50,9%) in BiV pacing. There were 2 deaths in group 1 and 3 in group 2 (OR 0.80, 95% CI 0.27–2.40). There were 0,98±3,17 hospitalizations per patient and there were no differences in HF hospitalizations between groups (OR 1.01, 95% CI 0.92–1.18) or NYHA after 6 months of CRT (p=0,364). Conclusion BiV pacing was not inferior to LV-only pacing in regard to cardiovascular death, HF hospitalizations and NYHA class improvement. There was no clear advantage for one pacing strategy over the other but more studies are still required. Funding Acknowledgement Type of funding sources: None.

Acute Hemodynamic Effects of Simultaneous and Sequential Multi-Point Pacing in Heart Failure Patients With an Expected Higher Rate of Sub-response to Cardiac Resynchronization Therapy: Results of Multicenter SYNSEQ Study.

The aim of the SYNSEQ (Left Ventricular Synchronous vs. Sequential MultiSpot Pacing for CRT) study was to evaluate the acute hemodynamic response (AHR) of simultaneous (3P-MPP syn) or sequential (3P-MPP seq) multi-3-point-left-ventricular (LV) pacing vs. single point pacing (SPP) in a group of patients at risk of a suboptimal response to cardiac resynchronization therapy (CRT). Twenty five patients with myocardial scar or QRS ≤ 150 or the absence of LBBB (age: 66 ± 12 years, QRS: 159 ± 12 ms, NYHA class II/III, LVEF ≤ 35%) underwent acute hemodynamic assessment by LV + dP/dtmax with a variety of LV pacing configurations at an optimized AV delay. The change in LV + dP/dt max (%ΔLV + dP/dt max) with 3P-MPP syn (15.6%, 95% CI: 8.8%-22.5%) was neither statistically significantly different to 3P-MPP seq (11.8%, 95% CI: 7.6-16.0%) nor to SPP basal (11.5%, 95% CI:7.1-15.9%) or SPP mid (12.2%, 95% CI:7.9-16.5%), but higher than SPP apical (10.6%, 95% CI:5.3-15.9%, p = 0.03). AHR (defined as a %ΔLV + dP/dt max ≥ 10%) varied between pacing configurations: 36% (9/25) for SPP apical, 44% (11/25) for SPP basal, 54% (13/24) for SPP mid, 56% (14/25) for 3P-MPP syn and 48% (11/23) for 3P-MPP seq.Fifteen patients (15/25, 60%) had an AHR in at least one pacing configuration. AHR was observed in 10/13 (77%) patients with a LBBB but only in 5/12 (42%) patients with a non-LBBB (p = 0.11). To conclude, simultaneous or sequential multipoint pacing compared to single point pacing did not improve the acute hemodynamic effect in a suboptimal CRT response population.Clinical Trial RegistrationClinicalTrials.gov, identifier: NCT02914457.

PO-688-01 ATRIOVENTRICULAR RESTORATION BY BIVENTRICULAR PACING FOR PATIENTS WITH PROLONGED PR INTERVAL: USE OF ECHOCARDIOGRAPHIC MEASUREMENTS

PR prolongation is associated with poor hemodynamic performance and may contribute to heart failure (HF). Previous research showed beneficial hemodynamic effects by invasive measurement of restoring atrioventricular (AV) coupling using biventricular (BiV) pacing in HF patients with AV dromotropathy (evidenced by PR interval prolongation), and no clear indication for cardiac resynchronization therapy (CRT).

Left bundle branch pacing in heart failure patients with left bundle branch block: A systematic review and meta-analysis.

The clinical benefit of cardiac resynchronization therapy (CRT) in heart failure patients with left bundle branch block (LBBB) has been demonstrated. However, a nonresponse rate of CRT nearly 1/3. Recent studies have reported left bundle branch pacing (LBBP) has achieved remarkable effect in CRT. This study aim to explore the efficacy and safety of LBBP in heart failure patients with LBBB. We searched PubMed, Cochrane Library, Web of science, and CNKI databases for studies about LBBP in heart failure patients with LBBB. QRS duration (QRSd), New York Heart Association (NYHA) classification, B-type natriuretic peptide (BNP) concentration, left ventricular ejection fraction (LVEF), left ventricular end-diastolic diameter (LVEDD), pacing threshold and other related data were extracted and summarized. A total of 6 studies were included, and the success rate of LBBP was 93.2%. Compared with baseline, LBBP could shorten QRSd (MD=61.23, 95% CI: 58.21-64.25, p<.01). Echocardiographic parameters including LVEF and LVEDD significantly improved (both with p<.01). Clinical outcomes including NYHA classification and BNP dramatically reduced (both with p<.01). Compared with biventricular pacing (BVP), LBBP could further improve QRSd, LVEF, LVEDD, and NYHA classification (all with p<.01). However, the pacing threshold at follow-up was 0.06 V higher than that at baseline (p<.01), and the incidence of complications was 2.4%. LBBP is effective and safe in heart failure patients with LBBB, whether it is better than BVP needs to be verified by randomized controlled trials.

Conduction system pacing in heart failure patients

Direct conduction system pacing delivers more physiological cardiac activation and can potentially correct intraventricular conduction disturbances and restore normal activation pathways. Permanent pacing that maintains cardiac electromechanical synchrony is essential in heart failure and reduced left ventricular ejection fraction. Conduction system pacing has recently emerged as an alternative to right ventricular pacing and biventricular resynchronization therapy. In this article, we review conduction system pacing in heart failure patients.

Impact of closed loop stimulation on prognostic cardiopulmonary variables in patients with chronic heart failure and severe chronotropic incompetence: a pilot, randomized, crossover study.

AimsClinical effects of rate-adaptive pacing in heart failure patients with chronotropic incompetence (CI) undergoing cardiac resynchronization therapy (CRT) remain unclear. Closed loop stimulation (CLS) is a new rate-adaptive sensor in CRT devices. We evaluated the effectiveness of CLS in CRT patients with severe CI, focusing primarily on key prognostic variables assessed by cardiopulmonary exercise (CPX) testing.Methods and resultsIn the randomized, crossover, multicentre BIO|CREATE study, 20 CRT patients with severe CI and NYHA Class II/III (60%/40%) were randomized 1:1 to the sequence DDD-40 mode to DDD-CLS mode, or the sequence DDD-CLS mode to DDD-40 mode (1 month in each mode). Patients underwent symptom-limited treadmill-based CPX test in each mode. An improvement (decrease) of the ventilatory efficiency (VE) slope of ≥5% during CLS was regarded as positive response to CLS. Seventeen patients with full data sets had a mean intra-individual VE slope change of −1.8 ± 3.0 (−4.1%) with CLS (P = 0.23). Eight patients (47%) were CLS responders, with a −6.1 ± 2.7 (−16.4%) slope change (P = 0.029). Compared to non-responders, CLS responders had a higher left ventricular (LV) ejection fraction (46 ± 3 vs. 36 ± 9%; P = 0.0070), smaller end-diastolic LV volume (121 ± 34 vs. 181 ± 41 mL; P = 0.0085), smaller end-systolic LV volume (65 ± 23 vs. 114 ± 39 mL; P = 0.0076), and were predominantly in NYHA Class II (P = 0.0498).ConclusionThe data of the present pilot study are compatible with the notion that CLS activation may improve VE slope in CRT patients with severe CI and less advanced heart failure. Further research is needed to determine the long-term clinical outcomes of CLS.

Efficacy of upgrading to left bundle branch pacing in patients with heart failure after right ventricular pacing.

Chronic right ventricular (RV) pacing is associated with an increased incidence of heart failure and mortality. Left bundle branch (LBB) pacing could produce near-physiological electrical activation and mechanical synchrony. We aimed to report the effects of upgrading to LBB pacing in heart failure patients after chronic RV pacing. The indications included pacing-induced cardiomyopathy (PICM) in Group 1 and heart failure after RV pacing with left ventricular ejection fraction (LVEF) ≥ 50% in Group 2. LBB pacing was achieved by penetrating the pacing lead to the subendocardium of left-sided interventricular septum through the venous access. Left ventricular activation time (LVAT) was measured from the pacing stimulus to the ascending peak of lead V5 or V6. All patients underwent clinical and echocardiographic evaluations before and after upgrading. Totally 27 patients (13 in Group 1 and 14 in Group 2) were consecutively enrolled. The mean follow-up time after upgrade was 10.4 ± 6.1 months. Paced QRS duration was significantly shortened from 174.1 ± 15.8milliseconds to 116.6 ± 11.7milliseconds (p<.0001). The mean LVAT was 83.2 ± 11.7milliseconds. LVEF increased from 40.3 ± 5.2% before upgrading to 48.1 ± 9.5% at follow-up in patients with PICM. Serum N-terminal probrain natriuretic peptide levels decreased and New York Heart Association classification improved in both groups. No upgrade-related complications were observed. Upgrading to LBB pacing was feasible and effective with improved cardiac function in heart failure patients with both reduced and preserved LVEF after RV pacing.

Efficacy and safety of left bundle branch area pacing versus biventricular pacing in heart failure patients with left bundle branch block: study protocol for a randomised controlled trial

IntroductionLeft bundle branch area pacing (LBBaP) has been accepted as a physiological pacing method that can yield narrow paced QRS waves. For patients with failed biventricular pacing (Bi-V), LBBaP is...

Economic value and cost-effectiveness of biventricular versus right ventricular pacing: results from the BLOCK-HF study

Aims: The Biventricular vs Right Ventricular Pacing in Heart Failure Patients with Atrioventricular Block (BLOCK-HF) demonstrated that biventricular (BiV) pacing resulted in better clinical and structural outcomes compared to right ventricular (RV) pacing in patients with atrioventricular (AV) block and reduced left ventricular ejection fraction (LVEF; ≤50%). This study investigated the cost-effectiveness of BiV vs RV pacing in the patient population enrolled in the BLOCK-HF trial.Methods: All-cause mortality, New York Heart Association (NYHA) Class distribution over time, and NYHA-specific heart failure (HF)-related healthcare utilization rates were predicted using statistical models based on BLOCK-HF patient data. A proportion-in-state model calculated cost-effectiveness from the Medicare payer perspective.Results: The predicted patient survival was 6.78 years with RV and 7.52 years with BiV pacing, a 10.9% increase over lifetime. BiV pacing resulted in 0.41 more quality-adjusted life years (QALYs) compared to RV pacing, at an additional cost of $12,537. The “base-case” incremental cost-effectiveness ratio (ICER) was $30,860/QALY gained. Within the clinical sub-groups, the highest observed ICER was $43,687 (NYHA Class I). Patients receiving combined BiV pacing and defibrillation (BiV-D) devices were projected to benefit more (0.84 years gained) than BiV pacemaker (BiV-P) recipients (0.49 years gained), compared to dual-chamber pacemakers.Conclusions: BiV pacing in AV block patients improves survival and attenuates HF progression compared to RV pacing. ICERs were consistently below the US acceptability threshold ($50,000/QALY). From a US Medicare perspective, the additional up-front cost associated with offering BiV pacing to the BLOCK-HF patient population appears justified.

Should His Bundle Pacing Be Preferred over Cardiac Resynchronization Therapy Following Atrioventricular Junction Ablation?

Atrial fibrillation (AF) and heart failure (HF) are associated with high morbidity and mortality, which is particularly detrimental when patients develop rapid ventricular rates (RVR). Atrioventricular junction (AVJ) ablation with pacemaker implantation has been used as a method of achieving rate control in patients with incessant AF with RVR. Right ventricular only pacing is known to be harmful in the setting of HF. His bundle pacing (HBP) and biventricular (BiV) pacing both offer durable pacing solutions that offer more physiologic activation. This review describes the benefits and drawbacks of HBP and BiV pacing in HF patients after AVJ ablation.

GW29-e1457 Long Term Outcomes of His Bundle Pacing in Heart Failure Patients with Left Bundle Branch Block

His bundle pacing (HBP) can potentially correct left bundle branch block (LBBB). We aimed to assess the efficacy of HBP to correct LBBB and long term clinical outcomes with HBP in heart failure (HF) patients. This is an observational study of HF patients with typical LBBB who were indicated for

Will His Bundle Pacing Make Cardiac Resynchronization Therapy Obsolete?

Although permanent cardiac pacing successfully restores a physiological heart rate in patients with atrioventricular block, it has become apparent in recent years that chronic right ventricular (RV) pacing can lead to serious adverse consequences such as adverse ventricular remodeling and heart failure. Algorithms that minimize RV pacing for patients with sinus node dysfunction or intermittent atrioventricular block are in widespread use to avoid the problems associated with chronic RV pacing. However, in patients with advanced atrioventricular block, high percentages of ventricular pacing are unavoidable. One approach to this problem is cardiac resynchronization therapy (CRT), in which a left ventricular lead in the coronary sinus paces simultaneously or near-simultaneously with an RV lead to allow more coordinated activation of the ventricles and avoid dyssynchrony. The BLOCK HF study (Biventricular versus Right Ventricular Pacing in Heart Failure Patients with Atrioventricular Block) showed that such an approach in patients with atrioventricular block and baseline left ventricular dysfunction (left ventricular ejection fraction [EF] ≤50% and New York Heart Association [NYHA] class I–III) led to better outcomes than RV pacing, including less adverse ventricular remodeling, a lower incidence of heart failure events, and better clinical composite scores.1 CRT has also proven to be valuable in patients with systolic heart failure without atrioventricular block but with evidence of conduction system disease manifested as a prolonged QRS duration, usually left bundle-branch block. Multiple trials …

8Pre-existing right ventricular paced heart failure patients upgraded to cardiac resynchronisation therapy devices: a retrospective assessment of the functional and clinical benefits

8Pre-existing right ventricular paced heart failure patients upgraded to cardiac resynchronisation therapy devices: a retrospective assessment of the functional and clinical benefits

Right Ventricular Versus Biventricular Pacing for Heart Failure and Atrioventricular Block.

The use of cardiac resynchronization therapy (CRT) is well accepted as an important option for the treatment of patients with systolic heart failure and prolonged QRS duration. CRT for patients with narrow QRS complexes is reserved for patients who are undergoing implantation of new or replacement pacemakers or implantable cardioverter defibrillators with an anticipated significant requirement for ventricular pacing. The Biventricular versus Right Ventricular Pacing in Heart Failure Patients with Atrioventricular Block (BLOCK HF) Trial examined the role of CRT in heart failure patients with atrioventricular block and demonstrated significantly better outcomes with CRT compared to right ventricular pacing. On the other hand, conflicting preliminary data were reported by the Biventricular Pacing for Atrioventricular Block to Prevent Cardiac Desynchronization (BioPace) Trial investigators. In this review, we will discuss the adverse consequences of chronic right ventricular pacing, the options of alternate pacing sites in the right ventricle versus biventricular pacing, and the findings from the BLOCK HF Trial as well as the preliminary data from the BioPace Trial. Our goal is to explore the role of biventricular pacing in patients with atrioventricular block.

Improvement in Clinical Outcomes With Biventricular Versus Right Ventricular Pacing: The BLOCK HF Study

BackgroundSustained right ventricular (RV) apical pacing may lead to deterioration in ventricular function and an increased risk of heart failure, especially in patients with pre-existing systolic dysfunction. The BLOCK HF (Biventricular Versus Right Ventricular Pacing in Heart Failure Patients With Atrioventricular Block) trial demonstrated that biventricular-paced patients had a reduced incidence of a composite endpoint of death, heart failure–related urgent care, and adverse left ventricular remodeling. ObjectivesIn a pre-specified analysis, this study examined clinical outcomes, including clinical composite score, quality of life (QOL), and change in New York Heart Association (NYHA) functional classification. MethodsThe BLOCK HF trial randomized patients with atrioventricular block, NYHA symptom class I to III heart failure, and left ventricular ejection fraction ≤50% to biventricular or RV pacing. NYHA functional classification, QOL, and clinical composite score were assessed at 6, 12, 18, and 24 months. Bayesian statistical methods were used, with the pre-specified metric of benefit being a posterior probability ≥0.95. ResultsPatients with biventricular pacing showed greater improvement in NYHA functional class at 12 months, with 19% improved, 61% unchanged, and 17% worsened, compared with 12%/62%/23% in the RV arm. QOL was improved through 12 months. At 6 months, clinical composite score was improved/unchanged/worsened in 53%/24%/24% in the biventricular arm compared with 39%/33%/28% in the RV arm. This improvement in clinical composite score was sustained through 24 months. ConclusionsFor patients with atrioventricular block and systolic dysfunction, biventricular pacing not only reduces the risk of mortality/morbidity, but also leads to better clinical outcomes, including improved QOL and heart failure status, compared with RV pacing. (Biventricular Versus Right Ventricular Pacing in Heart Failure Patients With Atrioventricular Block [BLOCK HF]; NCT00267098)

BLOCK HF: how far does it extend indications for cardiac resynchronization therapy?

The Biventricular versus Right Ventricular Pacing in Heart Failure Patients with Atrioventricular Block (BLOCK HF) trial, published in April 2013 [Curtis AB, Worley SJ, Adamson PB, et al; Biventricular versus Right Ventricular Pacing in Heart Failure Patients with Atrioventricular Block (BLOCK HF) Trial Investigators. Biventricular pacing for atrioventricular block and systolic dysfunction. N Engl J Med 2013; 368:1585-1593], explored whether cardiac resynchronization therapy (CRT) was superior to conventional pacing in patients with conventional indications for pacing, left ventricular dysfunction and NYHA (New York Heart Association) class I-III. The trial took 8 years and a source of concern is selection bias, because participating centers had an average of two patients enrolled per center, per year. Both the internal and external validity of the trial merit some comments. BLOCK HF showed a relatively low treatment effect of CRT as compared with other CRT trials. As a matter of fact, the absolute risk reduction for death or hospitalization because of heart failure was 4.8%, in a relatively long follow-up, with a number needed to treat (NNT) of 21, much higher than the NNT of other CRT trials. We estimate that at least one third of patients in BLOCK HF could meet current indications for CRT. Moreover, the study did not consider the additional risks and costs of CRT versus conventional pacing, both having important implications for cost-effectiveness estimates. For these and other reasons, uncertainties arise as to how far BLOCK HF extends current recommendations for CRT and how much it should be implemented in daily clinical practice.

Acute Effects of Biventricular Pacing in Heart Failure Patients with a Normal Ejection Fraction and Mechanical Dyssynchrony

Objectives: We tested the acute effects of resynchronization in heart failure patients with a normal (>50%) left ventricular (LV) ejection fraction (HFNEF) and mechanical dyssynchrony. Methods: Twenty-four HFNEF patients (72 ± 6 years, 5 male) with mechanical dyssynchrony (standard deviation of electromechanical time delay among 12 LV segments >35 ms) were studied with temporary pacing catheters in the right atrium, LV, and right ventricle (RV), and high-fidelity catheters for pressure recording. Using selected atrioventricular (AV) intervals of 60, 90, 120, 150, and 180 ms to optimize transmitral flow during simultaneous biventricular pacing, the RV-LV (VV) interval was then evaluated at RV30, RV15, 0, LV15, LV30, and LV45 (RV or LV indicates which ventricle was paced first, the number indicates by how many ms). Results: During simultaneous pacing, longer AV intervals were associated with improved LV pressure-derivative minimums and increased aortic pressures (p < 0.05 vs. normal sinus rhythm). In the VV interval from RV30 to LV45, there was a graded increase in the aortic velocity time integral and a decrease in dyssynchrony during simultaneous or LV-first pacing (p < 0.05 vs. normal sinus rhythm). Conclusions: For HFNEF patients with mechanical dyssynchrony, acute simultaneous biventricular or LV-first pacing with longer AV intervals reduced mechanical dyssynchrony and improved diastolic and systolic hemodynamics.