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Literature Review

Incidence and Predictors of Right Ventricular Pacing-Induced Cardiomyopathy in Patients With Complete Atrioventricular Block and Preserved Left Ventricular Systolic Function

Kiehl EL, Makki T, Kumar R, et al.: Heart Rhythm. 2016;13(12):2272-2278.

Reviewers: Igor Zhukov, MD1

  1. Emory University, Atlanta, GA
Background

Pacemaker use is a lifesaving technique in patients with a complete heart block (CHB) as well as other cardiac rhythm disturbances. However, new evidence of pacing-induced cardiac dysfunction prompts a further search for best management strategy, rapid identification, and proper adjustment of care for patients at risk of cardiac dysfunction. 

Methods

This is a retrospective observational study of a cohort of 823 patients with a CHB in a setting of a preserved left ventricular (LV) function, defined as left ventricular ejection fraction (LVEF) >50%. The patients who received a primary pacemaker for their heart block were then followed to detect the pacing-induced cardiomyopathy (PIC), defined as LVEF <40% or upgrade to the dual chamber pacing system (cardiac resynchronization therapy, or CRT).

A statistical analysis of the subgroup with PIC and one without was undertaken to detect the parameters that may predispose patients for PIC development. Demographic and medical histories were compared as well as pacing parameters, echocardiographic results, and whether CHB was associated with a cardiac procedure (eg, transcatheter aortic valve replacement, ablation).

Results

One hundred one patients qualified for the definition of PIC, with effective incidence of 12.3%. Mean LVEF in the affected group was 33.7 ± 7.4% vs 57.6 ± 6.1% (P<.001). A univariate analysis with a threshold of P<.1 suggested that older age, male sex, having more atrial arrhythmia, hypertension, chronic kidney disease, lower preimplant LVEF, placement of nonapical right ventricular (RV) lead, wider preimplant QRS morphology, and higher postimplant RV pacing burden was associated with development of PIC. When a multivariate analysis was undertaken with the above parameters and a P<.05 threshold, RV pacing burden and preimplant LVEF were the only 2 statistically significant variables, with hazard ratio (HR) 1.047 per 1% decrease of LVEF, and HR 1.011 per 1% increase of RV pacing burden respectively.

RV pacing also was analyzed as a dichotomous variable, with >40% RV pacing burden threshold carrying PIC HR of 3.19, and >20% RV pacing burden carrying PIC HR of 6.76.

Twenty-nine patients of the PIC subgroup were referred for cardiac resynchronization therapy after the development of depressed LV function; 28 biventricular upgrades were performed. In 25 patients for whom postupgrade echocardiography data was available, 21 met criteria for CRT improvement, with LVEF increase 18.5 ± 8.1%. Referral for CRT was more common in patients who had a more dramatic initial decrease of LVEF, as well as higher RV pacing burden, the latter not reaching statistical significance in this study.

Discussion

Optimal pacing strategy does not lend itself to a one-size-fits-all treatment recipe, and this study was only focused on a small subgroup of pacemaker recipients. It does confirm that previously published incidence of PIC exists even in the population with preserved baseline LVEF and demonstrates the importance of the follow-up surveillance and referral for resynchronization treatment if indicated. 

Current guidelines indicate that in an absence of cardiac symptoms, a routine echocardiography is not warranted for post pacemaker implantation.1 It also appears reasonable to avoid dual-chamber pacing in patients with normal EF, given increased procedural difficulty, higher chance of complications,2 and uncertain benefit of resynchronization therapy. Nonetheless, there may be a subgroup of patients with high RV pacing burden that may warrant further scrutiny. Minimally intrusive device interrogation, often available without leaving one's home and transmitted wirelessly, can be used to trigger a follow-up echocardiographic assessment and potentially a PIC-preventative intervention.

References
  1. Douglas PS, Garcia MJ, Haines DE, et al. ACCF/ASE/AHA/ASNC/ HFSA/HRS/SCAI/SCCM/SCCT/SCMR2011 Appropriate use criteria for echocardiography: a report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, American Society of Echocardiography, American Heart Association, American Society of Nuclear Cardiology, Heart Failure Society of America, Heart Rhythm Society, Society for Cardiovascular Angiography and Interventions, Society of Critical Care Medicine, Society of Cardiovascular Computed Tomography, Society of Cardiovascular Magnetic Resonance, American College of Chest Physicians. J Am Soc Echocardiogr. 2011;24(3):229-267.
  2. Arenas IA, Jacobson J, Lamas GA. Routine use of biventricular pacing is not warranted for patients with heart block. Circ Arrhythm Electrophysiol. 2015;8(3):730-738.