QRS Index as a Predictor of Response to Cardiac Resynchronization Therapy: A Systematic Review and Meta-Analysis

Area of Science:

• Cardiology
• Heart Failure Management
• Electrophysiology

Background:

• Cardiac resynchronization therapy (CRT) benefits heart failure (HF) patients with reduced ejection fraction and wide QRS, but 30-50% do not respond.
• The QRS Index, measuring QRS shortening post-CRT, is a potential response predictor.
• This study systematically evaluates the association between QRS Index and CRT response.

Purpose of the Study:

• To conduct a systematic review and meta-analysis.
• To evaluate the association between the QRS Index and CRT response.
• To explore predictors of CRT response using the QRS Index.

Main Methods:

• Systematic literature search of PubMed, Scopus, and Cochrane databases.
• Inclusion of studies reporting QRS Index in CRT responders and non-responders.
• Meta-analysis using a random-effects model; meta-regression for baseline parameters.

Main Results:

• Nine studies (1274 patients) analyzed; 760 responders (59%), 514 non-responders (41%).
• QRS Index significantly higher in responders (16.14 ± 13.19) vs. non-responders (7.22 ± 14.96) (mean difference: 8.76; p < 0.00001).
• Lower left ventricular end-systolic volume (LVESV) associated with higher QRS Index in responders (β = -0.0483; p = 0.0372).

Conclusions:

• The QRS Index is significantly elevated in CRT responders, indicating its utility as a response predictor.
• Findings support the QRS Index's role in predicting CRT success.
• Further research is needed to standardize clinical use and assess prognostic impact.