Clinical Investigations
Echocardiographic Assessment of Risk for Ventricular Arrhythmias
Burden of Ventricular Arrhythmias in Cardiac Resynchronization Therapy Defibrillation and Implantable Cardioverter-Defibrillator Recipients with Recovered Left Ventricular Ejection Fraction: The Additive Role of Speckle-Tracking Echocardiography

https://doi.org/10.1016/j.echo.2021.09.009Get rights and content

Highlights

  • LVEF may markedly improve in CRT-D recipients.

  • LV MD is a predictor of VAs.

  • MD improvement is inversely related to VAs risk, independently of LVEF improvement.

  • VA risk is not negligible in patients with LVEF improvement to >35% but elevated MD.

Background

Patients with heart failure undergoing cardiac resynchronization therapy with or without defibrillator function may exhibit recovery of left ventricular ejection fraction (LVEF) during follow-up. Mechanical dispersion (MD; the SD of time to peak longitudinal strain by two-dimensional speckle-tracking echocardiography) is a known predictor of life-threatening ventricular arrhythmias (VAs). Relationships among LVEF recovery, changes in MD, and incidence of VA are still not extensively investigated.

Methods

In this retrospective study, recipients of cardiac resynchronization therapy defibrillation (n = 183) or implantable cardioverter-defibrillators only (n = 87) underwent conventional and speckle-tracking echocardiography, both at baseline and after 10 to 12 months, and were followed clinically. Both a ≥10% increase in LVEF and a final LVEF > 35% defined echocardiographic response (EchoResp). Reduction in MD ≥10 msec defined MD response (MDResp). Risk for appropriate implantable cardioverter-defibrillator therapy for VAs was assessed using a multivariable Cox hazard model.

Results

The prevalence of EchoResp+ and MDResp+ was 39% and 46%, respectively. During follow-up (49.8 ± 33.5 months), 74 VA events occurred. The incidence rate (per 100 patient-years) of VAs was lowest in the EchoResp+/MDResp+ group (1.66%; 95% CI, 0.69%-3.99%), highest in the EchoResp−/MDResp− group (12.8%; 95% CI, 9.53%-17.2%; P < .0001), and intermediate in the EchoResp−/MDResp+ (5.5%; 95% CI, 3.3%-9.4%) or EchoResp+/MDResp− (5.3%; 95% CI, 3.0%-9.4%) group. Multivariable analysis showed that higher MD at follow-up (>71.4 msec) was associated with VAs independent of whether final LVEF was below or above the guideline-reported cutoff of 35% (P < .05).

Conclusions

Among ICD recipients, improvements in both left ventricular function and MD are associated with reduced risk for VAs. In patients whose follow-up LVEFs improved to >35%, risk for VAs, although substantially decreased, remained elevated in the presence of still elevated MD.

Section snippets

Population

Consecutive patients with HF with reduced ejection fraction with LVEFs ≤ 35%, QRS duration ≤ 130 msec, either ischemic or nonischemic cardiomyopathy, and New York Heart Association functional class ≥ II, for whom CRT-D device implantation was planned according to current guidelines1,2 were enrolled in this observational retrospective study. A further cohort of patients undergoing ICD therapy according to primary prevention criteria (nonischemic etiology and persistent LVEF ≤ 35% after ≥3 months

Results

From January 2008 to December 2018, 361 patients were initially screened. Of these, 40 did not met the inclusion criteria, and eight were lost to follow-up. Another 33 patients were excluded because they underwent follow-up echocardiography outside the permitted window, and 10 were excluded because of incomplete echocardiographic examinations. Therefore, the final study population consisted of 270 patients. Baseline clinical and echocardiographic characteristics of the overall study population

Discussion

In the present study, we assessed the relationships among changes in MD, improvement in LVEF at follow-up, and subsequent risk for life-threatening VAs requiring ICD intervention in patients with LV dysfunction treated with either CRT-D or ICD only. We found that (1) among candidates for primary prevention ICD, LVEF significantly improved over time, and as expected, this improvement was evident only in CRT-D patients; (2) the risk for VA occurrence during follow-up decreased in parallel with

Conclusion

Among CRT-D and ICD candidates, the risk for VAs requiring appropriate shock progressively decreased with improvement in LV function and reduction in MD. In patients whose follow-up LVEFs improved to >35%, the risk for VAs, although markedly decreased, remained high in the presence of persistently high values of MD at follow-up.

References (28)

Cited by (6)

Conflicts of Interest: None.

This work has been funded in part by Ministero della Salute NET-016-02363853 and by Basic Research fund from the Department of Medicine, University of Perugia, D.D. 295/19.

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