Introduction
What is CSP and how did we get here?
Early pacemaker - Revolutionary, life-saving, bulky - 1950s
More physiologic pacing
- AV synchrony
- Dual chamber pacemaker - 1970s
- Chronotropy
- Rate adaptive pacing - 1980s
- Ventricular synchrony
- Multi-site pacing
- Biventricular pacing - 1990s
Conduction system pacing
- A paradigm shift !
- Difficult to achieve synchrony with myocardial pacing
- Use the native conduction system to activate myocardium synchronously
Deshmukh P, Casavant DA, Romanyshyn M, Anderson K. Permanent, direct His-bundle pacing: a novel approach to cardiac pacing in patients with normal His-Purkinje activation. Circulation. 2000 Feb 29;101(8):869-77. doi: 10.1161/01.cir.101.8.869. PMID: 10694526.
Where we are today
What is CRT ?
What are the modes of CRT today ?
- Biventricular pacing
- Conduction system pacing - HBP, LBP
- Conduction system optimized BiV pacing - HOT, LOT
Modes of CRT today
In this talk
- Which mode of CRT for whom
- Evidence
- Guidelines
- How I choose
- Today
New therapy - How to approach
Situations discussed
- LV dysfunction, EF < 35%, wide QRS of LBBB morphology (Classic CRT indication)
- Bradycardia with significant ventricular pacing requirement, LVEF < 50% (Brady with high PICM likelihood)
- Bradycardia with significant ventricular pacing requirement, LVEF > 50% (Brady with low PICM likelihood)
- LV dysfunction, wide QRS of non LBBB morphology (Non classic CRT indication, non LBBB wide QRS)
Classic CRT indication
Illustrative case
- 54 year old male, non DM
- Severe LV dysfunction
- NYHA III on medical management
- Normal coronaries
ECG
Options
- BiV CRT
- HB CRT
- LB CRT
- HOT CRT / LOT CRT
Evidence - LB or HB ?
HBP - Intermediate term outcomes
- Pacing threshold > 2.5V at 1.0 ms - 28%
- Loss of HB capture - 9%
- Lead revision - 7.6%
- Median PG longevity - 5.8 years
Zanon F et al. Long term performance and safety of His bundle pacing: a multicenter experience. J Cardiovasc Electrophysiol. 2019; 30: 1594-1601
LBBAP - Intermediate term outcomes (1.5 yrs)
- Acute success - 97.8%
- Threshold - 0.7 mV at 0.4 ms
- Increase in threshold with loss of capture - 1%
- Dislodgement - 0.3 %
- Perforation - 0.3 %
- Long term complications - ?
Lan Su et al. Long-Term Safety and Feasibility of Left Bundle Branch Pacing in a Large Single-Center Study. Circulation: Arrhythmia and Electrophysiology. 2021;14:e009261. https://doi.org/10.1161/CIRCEP.120.009261
Evidence - BiV-CRT vs LB-CRT
RCT - BiV versus LB
Wang Y, Zhu H, Hou X, Wang Z, Zou F, Qian Z, Wei Y, Wang X, Zhang L, Li X, Liu Z, Xue S, Qin C, Zeng J, Li H, Wu H, Ma H, Ellenbogen KA, Gold MR, Fan X, Zou J; LBBP-RESYNC Investigators. Randomized Trial of Left Bundle Branch vs Biventricular Pacing for Cardiac Resynchronization Therapy. J Am Coll Cardiol. 2022 Sep 27;80(13):1205-1216. doi: 10.1016/j.jacc.2022.07.019.
Non RCT - BiV versus LB
Diaz JC, Sauer WH, Duque M, Koplan BA, Braunstein ED, Marín JE, Aristizabal J, Niño CD, Bastidas O, Martinez JM, Hoyos C, Matos CD, Lopez-Cabanillas N, Steiger NA, Kapur S, Tadros TM, Martin DT, Zei PC, Tedrow UB, Romero JE. Left Bundle Branch Area Pacing Versus Biventricular Pacing as Initial Strategy for Cardiac Resynchronization. JACC Clin Electrophysiol. 2023 Aug;9(8 Pt 2):1568-1581. doi: 10.1016/j.jacep.2023.04.015.
Evidence - LB versus LOT
QRS duration - LOT CRT
Jastrzębski M, Moskal P, Huybrechts W, Curila K, Sreekumar P, Rademakers LM, Ponnusamy SS, Herweg B, Sharma PS, Bednarek A, Rajzer M, Vijayaraman P. Left bundle branch-optimized cardiac resynchronization therapy (LOT-CRT): Results from an international LBBAP collaborative study group. Heart Rhythm. 2022 Jan;19(1):13-21. doi: 10.1016/j.hrthm.2021.07.057.
QRS duration - LOT CRT
Comparison of electrocardiographic parameters between left bundle optimized cardiac resynchronization therapy (LOT-CRT) and left bundle branch pacing—cardiac resynchronization therapy (LBBP-CRT). Chinmay Parale, Dinakar Bootla, Ashish Jain, Santhosh Satheesh, Avinash Anantharaj, Shaheer Ahmed, Suresh Kumar Sukumaran, Sridhar Balaguru and Raja Selvaraj. Pacing and Clinical Electrophysiology 2023; 46: 840-847
RCT
- 27 patients - NICMP, LBBB and LVEF < 35
- Randomised to LOT-CRT vs LB-CRT
- 80% successful LB capture
- Delta LVEF 14+-12.4 vs 11.4+-14.2
- Response (clinical and echo) - 82% vs 71.4%
- Super response - 27% vs 21%
Chinmay Parale … Raja Selvaraj. Unpublished data
Classic CRT indication - Summary of evidence
- Evidence for superiority of LB-CRT over BiV-CRT not strong
- However, it appears non inferior, likely superior
- LOT-CRT may not be better than LB-CRT in all
- However, in select patients may provide benefit
- Selection by QRSd or LVAT
What do the guidelines say ?
HRS 2023
2023 HRS/APHRS/LAHRS guideline on cardiac physiologic pacing for the avoidance and mitigation of heart failure. Heart Rhythm. Volume 20, Issue 9e17-e91September 2023
What do I do ?
CS venogram
CS lead through subselective catheter
Left bundle lead in place
Final position
Final ECG
What will I do in two years?
- LB lead first
- QRS duration / LVAT to decide on CS lead
- LB-CRT / LOT-CRT
Bradycardia with substantial pacing requirement
Substantial pacing requirement - MOST study
Sweeney MO, Hellkamp AS, Ellenbogen KA, Greenspon AJ, Freedman RA, Lee KL, Lamas GA; MOde Selection Trial Investigators. Adverse effect of ventricular pacing on heart failure and atrial fibrillation among patients with normal baseline QRS duration in a clinical trial of pacemaker therapy for sinus node dysfunction. Circulation. 2003 Jun 17;107(23):2932-7. doi: 10.1161/01.CIR.0000072769.17295.B1.
Deleterious effects of RV pacing
- Avoid RV pacing when possible
- High incidence of PICM with substantial pacing, more risk with reduced EF
- CRT may reduce PICMP
Biventricular pacing reduces PICMP
Yu CM, Chan JY, Zhang Q, Omar R, Yip GW, Hussin A, Fang F, Lam KH, Chan HC, Fung JW. Biventricular pacing in patients with bradycardia and normal ejection fraction. N Engl J Med. 2009 Nov 26;361(22):2123-34. doi: 10.1056/NEJMoa0907555. Epub 2009 Nov 15. PMID: 19915220.
HB pacing reduces PICMP
Vijayaraman P, Naperkowski A, Subzposh FA, Abdelrahman M, Sharma PS, Oren JW, Dandamudi G, Ellenbogen KA. Permanent His-bundle pacing: Long-term lead performance and clinical outcomes. Heart Rhythm. 2018 May;15(5):696-702. doi: 10.1016/j.hrthm.2017.12.022. Epub 2017 Dec 20. PMID: 29274474.
LB pacing reduces PICMP when pacing > 20%
Clinical outcomes of left bundle branch area pacing compared to right ventricular pacing: Results from the Geisinger-Rush Conduction System Pacing Registry. Sharma, Parikshit S. et al. Heart Rhythm, Volume 19, Issue 1, 3 - 11
BiV pacing in AV block with LV dysfunction
Curtis AB, Worley SJ, Adamson PB, Chung ES, Niazi I, Sherfesee L, Shinn T, Sutton MS; 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 Apr 25;368(17):1585-93. doi: 10.1056/NEJMoa1210356. PMID: 23614585.
Guidelines
2023 HRS/APHRS/LAHRS guideline on cardiac physiologic pacing for the avoidance and mitigation of heart failure. Heart Rhythm. Volume 20, Issue 9e17-e91September 2023
What I do
- All bradycardia patients
- Bradycardia with substantial pacing requirement
- Bradycardia, substantial pacing requirement and EF < 50
Non LBBB CRT indication
Evidence - BiV for non LBBB
Sipahi I, Chou JC, Hyden M, Rowland DY, Simon DI, Fang JC. Effect of QRS morphology on clinical event reduction with cardiac resynchronization therapy: meta-analysis of randomized controlled trials. Am Heart J. 2012 Feb;163(2):260-7.e3. doi: 10.1016/j.ahj.2011.11.014. PMID: 22305845; PMCID: PMC4113034.
Registry data - BiV for Non LBBB
Kawata H, Bao H, Curtis JP, Minges KE, Mitiku T, Birgersdotter-Green U, Feld GK, Hsu JC. Cardiac Resynchronization Defibrillator Therapy for Nonspecific Intraventricular Conduction Delay Versus Right Bundle Branch Block. J Am Coll Cardiol. 2019 Jun 25;73(24):3082-3099. doi: 10.1016/j.jacc.2019.04.025.
Evidence - HBP for RBBB
Sharma PS, Naperkowski A, Bauch TD, Chan JYS, Arnold AD, Whinnett ZI, Ellenbogen KA, Vijayaraman P. Permanent His Bundle Pacing for Cardiac Resynchronization Therapy in Patients With Heart Failure and Right Bundle Branch Block. Circ Arrhythm Electrophysiol. 2018 Sep;11(9):e006613. doi: 10.1161/CIRCEP.118.006613.
Personalised CRT
Personalized cardiac resynchronization therapy guided by real-time electrocardiographic imaging for patients with non–left bundle branch block. Tam, Mark T.K. et al. Heart Rhythm, Volume 21, Issue 7, 1047 - 1056
Personalised CRT
Personalized cardiac resynchronization therapy guided by real-time electrocardiographic imaging for patients with non–left bundle branch block. Tam, Mark T.K. et al. Heart Rhythm 2024, Volume 21, Issue 7, 1047 - 1056
Guidelines
2023 HRS/APHRS/LAHRS guideline on cardiac physiologic pacing for the avoidance and mitigation of heart failure. Heart Rhythm. Volume 20, Issue 9e17-e91September 2023
What I do ?
- Select patients - QRS duration, symptoms
- Understand and discuss lower chance of benefit
- Offer conduction system pacing alone or in combination with BiV
Summary
- CRT more common as therapeutic and prophylactic pacing therapy
- Multiple modalities of providing CRT
- CSP non inferior to BiV, most likely superior
- LB pacing preferred mode of CSP for most patients
- Use as first line therapy, rescue therapy and adjunctive therapy for CRT