Left Ventricular Versus Biventricular for Cardiac Resynchronization Therapy
2011; Lippincott Williams & Wilkins; Volume: 124; Issue: 25 Linguagem: Inglês
10.1161/circulationaha.111.070763
ISSN1524-4539
Autores Tópico(s)Neurological disorders and treatments
ResumoHomeCirculationVol. 124, No. 25Left Ventricular Versus Biventricular for Cardiac Resynchronization Therapy Free AccessEditorialPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessEditorialPDF/EPUBLeft Ventricular Versus Biventricular for Cardiac Resynchronization TherapyComparable But Not Equal Leslie A. Saxon, MD Leslie A. SaxonLeslie A. Saxon From the University of Southern California, Los Angeles. Originally published20 Dec 2011https://doi.org/10.1161/CIRCULATIONAHA.111.070763Circulation. 2011;124:2803–2804The primary mechanism of benefit associated with cardiac resynchronization therapy (CRT) is attributed to improvement in left ventricular (LV) function resulting from restoration of LV contractile synchrony.1,2 The vast majority of implanted CRT-capable devices are programmed to provide the therapy by simultaneous pacing of the right ventricle and LV (biventricular stimulation). This mode of CRT delivery has been the mode best tested in large-scale clinical trials that have demonstrated improvement in functional, anatomic, and event-driven outcomes.3–6 The reasons for the more thorough evaluation of biventricular stimulation compared with LV stimulation alone are largely practical in nature. Early studies of CRT systems were designed to demonstrate the safety and efficacy of CRT. Long-term transvenous epicardial LV stimulation was not an established therapy, and LV lead performance was unknown. Biventricular stimulation allowed backup pacing and sensing if the LV lead failed. Additionally, all bradycardia pacing and defibrillating lead timing and therapy delivery are determined by right ventricular lead–based sensing. These considerations necessitated the presence of a right ventricular lead in long-term studies of CRT. There was also the early short-term observation that short-term stimulation results in similar mechanical synchrony with LV or biventricular stimulation, but electric dispersion appears to be increased with LV stimulation. This finding raised concern that LV stimulation alone could create a more favorable milieu for the occurrence of ventricular proarrhythmia.1,7Article see p 2874The left ventricular versus simultaneous biventricular pacing in patients with heart failure and a QRS complex greater or equal to 120 milliseconds study (GREATER-EARTH) investigators report 6-month data collected in 103 patients prospectively randomized in a double-blind multicenter crossover trial of LV versus biventricular CRT.8 Consistent with other long-term studies (Table9–12), LV stimulation was not reported to be superior to biventricular stimulation for CRT, although it appears to be safe and effective. A novel finding of the study is that patients not responding to either LV or biventricular stimulation have the potential to improve (31% and 17% of nonresponders, respectively) if stimulated in the other mode. The GREATER-EARTH trial enrolled a very well medically treated group of patients with LV dysfunction, advanced symptom class heart failure, and QRS delay. The investigators report a >94% and 99% use of β-receptor blocker and angiotensin-converting enzyme inhibitor or receptor blocker therapy before initiating CRT in all study patients. This was due to the study requirement of a 2- to 8-week medication stabilization period after implantation and before randomization. This requirement differentiates this trial and helps ensure that the findings are a true assessment of CRT and not of other confounding factors, such as functional or structural improvement resulting from medical therapy or exercise training effect. The functional and anatomic end points used in GREATER-EARTH are similar to those used in other long-term studies comparing LV and biventricular CRT and show similar magnitude of improvements. Unlike one other trial that also studied LV or biventricular stimulation delivered for 6 months that reported a greater reduction in LV end-diastolic volumes with biventricular CRT, the GREATER-EARTH trial indicates similar reductions in LV volumes regardless of CRT mode.10 There also was no difference in the incidence of sustained atrial or ventricular arrhythmias according to CRT mode in the GREATER-EARTH trial. However, these data cannot be considered definitive, relative to arrhythmia risk, because the follow-up was limited to 6 months and there was no assessment of mortality or hospitalization.Table. Clinical Studies of Left Ventricular Versus Biventricular Stimulation for Cardiac Resynchronization TherapyStudy AuthorsReferenceYearPatients Studied, nStudy DesignPrimary End PointsFindingsThibault et al (GREATER-EARTH)820111036-mo crossover BiV/LV CRTExercise durationLV not superior to BiV CRTBoriani et al (B-LEFT)920101766-mo 2-arm BiV/LV CRTFunctional class, reverse remodelingLV noninferior to BiV CRTRao et al (DECREASE HF)1020073066-mo 3-arm LV BIV/LV offset CRTEchocardiographic measures of reverse modelingBiV resulted in greater reduction in LV volume than LV CRTBlanc et al (none)112004226-mo single-arm LV CRTFunctional class, 6-min walk, peak V̇O2Significant improvement with LV CRT vs baselineGasparini et al (BELIEVE)1220066612-mo single-arm LV/BiV CRTLV ejection fraction, 6-min walkSimilar benefit for LV and BiV CRTBiV indicates biventricular; arrhythmias; LV, left ventricular; CRT, cardiac resynchronization therapy; B-LEFT, Biventricular Versus Left Univentricular Pacing With ICD Back-Up in Heart Failure Patients; DECREASE HF, a randomized trial comparing simultaneous biventricular pacing, sequential biventricular pacing, and left ventricular pacing; and BELIEVE, Bi vs Left Ventricular Pacing: An International Pilot Evaluation on Heart Failure Patients With Ventricular Arrhythmias.The well-conducted GREATER-EARTH trial has significance because it provides some rationale for initiating a programming change to an alternative mode for a CRT device recipient who does not demonstrate clinical improvement. The data also provide indirect support for changing modes in a CRT recipient who demonstrates clinical worsening of heart failure status, a very significant clinical issue associated with long-term CRT device therapy.8–12It is unclear whether LV CRT offers any advantage to the future development of CRT LV leads or devices beyond biventricular CRT. For the foreseeable future, sensing and treating bradyarrhythmias and tachyarrhythmias will require a right ventricular lead. The investment in clinical science required to establish the epicardial transvenous LV lead for these purposes is unlikely to occur. Current transvenous LV lead development is directed more toward solving clinical issues like high capture thresholds and phrenic nerve stimulation as part of a biventricular system. There may a greater interest in LV CRT with stimulation technologies that do not require a transvenous lead such as ultrasound-mediated pacing because leadless CRT may offer distinct advantages by reducing lead-related complications and may offer a more site-specific option to placement of the LV lead.13It should be noted that the total number of patients studied with LV CRT over a nearly 10-year interval and with no more than 6 to 12 months of follow-up is <500. In addition, unlike the confluence of consistent data from 2 large-scale clinical trials on biventricular CRT, no study that has evaluated LV CRT has been powered to assess hospitalization and mortality outcomes.2–6 This is important because the mechanisms of mortality benefit with biventricular CRT may extend beyond the establishment of mechanical synchrony with LV stimulation and may be right ventricular lead dependent. Therefore, the major impact of the GREATER-EARTH trial is that it provides clinicians with some confidence that reprogramming a CRT device to LV only, in cases in which the response to therapy is suboptimal or has attenuated over time, is a reasonable and safe option.13DisclosuresDr Saxon has received research grants from and also serves as consultant to or on the advisory board for St Jude Medical, Medtronic Inc, and Boston Scientific Corp.FootnotesThe opinions expressed in this article are not necessarily those of the editors or of the American Heart Association.Correspondence to Leslie A. Saxon, MD, University of Southern California, Keck School of Medicine, Cardiovascular and Thoracic Institute, 1510 San Pablo St, Ste 322, Los Angeles, CA 90033. E-mail [email protected]eduReferences1. Leclercq C, Faris O, Tunin R, Johnson J, Kato R, Evans F, Spinelli J, Halperin H, McVeigh E, Kass DA. Systolic improvement and mechanical resynchronization does not require electrical synchrony in the dilated failing heart with left bundle-branch block. Circulation. 2002; 106:1760–1763.LinkGoogle Scholar2. Saxon LA, Boehmer JP, Hummel J, Kacet S, De Marco T, Naccarelli G, Daoud E; VIGOR CHF and VENTAK CHF Investigators. Biventricular pacing in patients with congestive heart failure: two prospective randomized trials. Am J Cardiol. 1999; 83:120D–123D.CrossrefMedlineGoogle Scholar3. Saxon LA, Hayes DL, Gilliam FR, Heidenreich PA, Day JD, Seth M, Meyer T, Jones PW, Boehmer JP. Long-term outcome after ICD and CRT implant and the influence of remote device follow-up: the ALTITUDE Survival Study. Circulation. 2010; 122:2359–2367.LinkGoogle Scholar4. Abraham WT, Fisher WG, Smith AL, Delurgio DB, Leon AR, Loh E, Kocovic DZ, Packer M, Clavell AL, Hayes DL, Ellestad M, Trupp RJ, Underwood J, Pickering F, Truex C, McAtee P, Messenger J. Cardiac resynchronization in chronic heart failure. N Engl J Med. 2002; 346:1845–1853.CrossrefMedlineGoogle Scholar5. Bristow MR, Saxon LA, Boehmer J, Krueger S, Kass DA, De Marco T, Carson P, DiCarlo L, DeMets D, White BG, DeVries DW, Feldman AM. Cardiac-resynchronization therapy with or without an implantable defibrillator in advanced chronic heart failure. N Eng J Med. 2004; 350:2140–2150.CrossrefMedlineGoogle Scholar6. Cleland JG, Daubert JC, Erdmann E, Freemantle N, Gras D, Kappenberger L, Tavazzi L; Cardiac Resynchronization-Heart Failure (CARE-HF) Study. The effect of cardiac resynchronization on morbidity and mortality in heart failure. N Engl J Med. 2005; 352:1539–1549.CrossrefMedlineGoogle Scholar7. Auricchio A, Stellbrink C, Block M, Sack S, Vogt J, Bakker P, Klein H, Kramer A, Ding J, Salo R, Tockman B, Pochet T, Spinelli J. Effect of pacing chamber and atrioventricular delay on acute systolic function of paced patients with congestive heart failure: the Pacing Therapies for Congestive Heart Failure Study Group; the Guidant Congestive Heart Failure Research Group. Circulation. 1999; 99:2993–3001.LinkGoogle Scholar8. Thibault B, Ducharme A, Harel F, White M, O'Meara E, Guertin M-C, Lavoie J, Frasure-Smith N, Dubuc M, Guerra P, Macle L, Rivard L, Roy D, Talajic M, Khairy P. Left ventricular versus simultaneous biventricular pacing in patients with heart failure and a QRS complex ≥120 milliseconds. Circulation. 2011; 124:2874–2881.LinkGoogle Scholar9. Boriani G, Kranig W, Donal E, Calo L, Casella M, Delarche N, Lozano IF, Ansalone G, Biffi M, Boulogne E, Leclercq C. A randomized double-blind comparison of biventricular versus left ventricular stimulation for cardiac resynchronization therapy: the Biventricular Versus Left Univentricular Pacing With ICD Back-Up in Heart Failure Patients (B-LEFT HF) trial. Am Heart J. 2010; 159:1052–1058.CrossrefMedlineGoogle Scholar10. Rao RK, Kumar UN, Schafer J, Viloria E, De Lurgio D, Foster E. Reduced ventricular volumes and improved systolic function with cardiac resynchronization therapy: a randomized trial comparing simultaneous biventricular pacing, sequential biventricular pacing, and left ventricular pacing. Circulation. 2007; 115:2136–2144.LinkGoogle Scholar11. Blanc JJ, Bertault-Valls V, Fatemi M, Gilard M, Pennec PY, Etienne Y. Midterm benefits of left univentricular pacing in patients with congestive heart failure. Circulation. 2004; 109:1741–1744.LinkGoogle Scholar12. Gasparini M, Bocchiardo M, Lunati M, Ravazzi PA, Santini M, Zardini M, Signorelli S, Passardi M, Klersy C. Comparison of 1-year effects of left ventricular and biventricular pacing in patients with heart failure who have ventricular arrhythmias and left bundle-branch block: the Bi vs Left Ventricular Pacing: An International Pilot Evaluation on Heart Failure Patients With Ventricular Arrhythmias (BELIEVE) multicenter prospective randomized pilot study. Am Heart J. 2006; 152:155.e1–155.e7.Google Scholar13. Lee KL, Tse HF, Echt DS, Lau CP, Temporary leadless pacing in heart failure patients with ultrasound-mediated stimulation energy and effects on acoustic window. Heart Rhythm. 2009; 6:742–748.CrossrefMedlineGoogle Scholar Previous Back to top Next FiguresReferencesRelatedDetailsCited By Zacà V, Murphy T and Biffi M (2018) Electrical manipulation of the failing heart, Heart Failure Reviews, 10.1007/s10741-018-9732-x, 23:6, (885-896), Online publication date: 1-Nov-2018. Vyas A and Lokhandwala Y (2017) When limited by cost in CRT-be a leftist!, Indian Pacing and Electrophysiology Journal, 10.1016/j.ipej.2017.05.003, 17:3, (70-71), Online publication date: 1-May-2017. Capucci A, Luzi M, Cipolletta L and Molini S (2016) Health economic concerns on cardiac rhythm management devices longevity and how to overcome them, Expert Review of Medical Devices, 10.1586/17434440.2016.1142871, 13:3, (297-303), Online publication date: 3-Mar-2016. December 1, 2011Vol 124, Issue 25 Advertisement Article InformationMetrics © 2011 American Heart Association, Inc.https://doi.org/10.1161/CIRCULATIONAHA.111.070763PMID: 22184041 Originally publishedDecember 20, 2011 KeywordsEditorialscardiac resynchronization therapyPDF download Advertisement SubjectsArrhythmiasPacemaker
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