Cardiac Resynchronization Therapy in Heart Failure: Do Evidence-Based Guidelines Follow the Evidence?

Coronary Artery Disease and Heart Failure: Medical Management and Future Direction

Coronary artery disease (CAD) is a leading etiology of heart failure (HF) and serves as a significant therapeutic target to ameliorate HF-associated morbidity and mortality. Key management considerations include pharmacologic treatment, electrophysiological devices, and coronary revascularization, aimed toward preventing CAD progression, left ventricular remodeling, sudden death, and reinfarction. The optimal revascularization strategy for patients with CAD and HF who are surgical candidates requires careful assessment of each patients' unique risk/benefit profile and individual preferences. Several novel pharmacologic agents are in development with hopes of adding to the armamentarium of treatment of CAD and HF.

QRS area as a predictor of cardiac resynchronization therapy response: a systematic review and meta-analysis

BACKGROUND

QRS area, a three-dimensional QRS complex, is a novel vectorcardiography method of measuring the magnitude of electrical forces in the heart. Hypothetically, a greater QRS area denotes higher dyssynchrony and indicates potential benefits from cardiac resynchronization therapy (CRT). Previous studies suggest a positive correlation between QRS area and the degree of response to CRT, but its clinical use remains unclear. We performed a meta-analysis of the relationship between QRS area and survival benefit following CRT.

METHODS

We comprehensively searched the MEDLINE, EMBASE, and Cochrane databases from inception to August 2021. We included studies with prospective and retrospective cohort designs that reported QRS area before CRT and total mortality. Data from each study were analyzed using a random-effects model. The results were reported as a hazard ratio (HR) and 95% confidence intervals.

RESULTS

Five observational studies including 4,931 patients were identified. The cut-off values between large and small QRS areas ranged from 102-116 μVs. Our analysis showed a larger QRS area was statistically associated with increased 5-year survival in patients implanted with CRT (HR pooled 0.48, 95% CI 0.46-0.51, I² = 54%, P < 0.0001). Greater QRS area reduction (pre- and post-implantation) were associated with a lower total mortality rate (HR pooled 0.45, 95% CI 0.38-0.52, I² = 0%, P < 0.0001).

CONCLUSION

Larger pre-implantation QRS area was associated with increased survival after CRT. QRS area reduction following CRT implantation was also associated with lower mortality. QRS area may potentially become an additional selection criterion for CRT implantations. This article is protected by copyright. All rights reserved.

The stricter criteria for Class I CRT indication suggested by the 2016 ESC Guidelines reliably exclude patients with a worse prognosis in comparison with the 2013 ESC indication criteria

BACKGROUND

The European Society of Cardiology (ESC) Guidelines published in 2016 modified indications for cardiac resynchronization therapy (CRT) in comparison with the 2013 ESC Guidelines. The aim of this analysis was to evaluate the impact of the stricter criteria suggested by the 2016 ESC Guidelines on patient outcome in a real-world population.

METHODS

We collected data on 930 consecutive patients with complete outcome information who had undergone CRT implantation from 2011 to 2013 from the CRT-MORE registry. Patients were classified according to 2013 (Reference) and 2016 (Current) ESC Guidelines. The primary end-point of the study was death from any cause and heart failure hospitalization.

RESULTS

According to the Reference Guidelines, 650 (69.9%) patients met Class I indications, 190 (20.4%) Class IIa, 39 (4.2%) Class IIb and 51 (5.5%) Class III. According to the Current Guidelines, 563 (60.5%) patients met Class I indications, 145 (15.6%) Class IIa, 108 (11.6%) Class IIb and 114 (12.3%) Class III. On comparing the Reference and Current Guidelines, the 538 patients who confirmed their Class I indication had a better outcome in terms of freedom from the combined end-point of heart failure (HF) hospitalization or death from any cause (hazard ratio (HR) of 0.64; 95% CI 0.42 to 0.99; p = 0.0436) when compared to the 112 patients who lost their class I indication (84 moved to class IIb and 28 moved to class III).

CONCLUSIONS

The stricter criteria for Class I CRT indication suggested by the 2016 ESC Guidelines excluded about 20% of patients with a worse prognosis.

CLINICAL TRIAL REGISTRATION

CRT MORE: Cardiac Resynchronization Therapy Modular Registry URL: http://clinicaltrials.gov/Identifier:NCT01573091.