Does presence of left ventricular contractile reserve improve response to cardiac resynchronization therapy? An
Nikolaos Papageorgiou1, Rui Providência2, Pier D Lambiase3
1Echocardiography Laboratory, Barts Heart Centre, St Bartholomew's Hospital, London, UK; Electrophysiology Department, Barts Heart Centre, St Bartholomew's Hospital, London, UK.
Insights
Contractile reserve (CR) predicts better response to cardiac resynchronization therapy (CRT). Identifying CR improves CRT outcomes, especially in patients with narrower QRS complexes, potentially reducing non-response rates.
Area of Science:
- Cardiology
- Medical Technology
- Heart Failure Management
Background:
- Cardiac resynchronization therapy (CRT) is a treatment for heart failure.
- A significant portion of patients (up to one-third) do not respond to CRT.
- Predictors of CRT response, such as contractile reserve (CR), require further investigation.
Purpose of the Study:
- To determine if the presence of contractile reserve (CR) improves response to cardiac resynchronization therapy (CRT).
- To investigate whether clinical factors modulate the relationship between CR and CRT response.
Main Methods:
- A meta-analysis was conducted, searching PubMed, EMBASE, and Cochrane databases.
- Studies examining CRT response stratified by the presence or absence of CR were included.
- Response was classified as clinical or echocardiographic, comparing outcomes between patients with and without CR.
Main Results:
- The analysis included 824 patients from 12 studies.
- Presence of left ventricular CR significantly reduced both echocardiographic and clinical non-responders to CRT (OR < 0.33, p < 0.00001).
- Meta-regression indicated CR was associated with lower non-responder rates, more pronounced with narrower QRS complexes.
Conclusions:
- Identifying contractile reserve (CR) is linked to improved cardiac resynchronization therapy (CRT) response.
- QRS width may moderate CRT response heterogeneity.
- Combining CR assessment with QRS width could optimize patient selection and predict CRT outcomes.
Background:
Up to a third of patients undergoing cardiac resynchronization therapy (CRT) do not have a clinical or echocardiographic response. It is also unclear, whether contractile reserve (CR) could predict CRT response. This meta-analysis examines whether the presence of CR improves response to CRT and whether this is modulated by other clinical factors.
Methods:
Search of PubMed/EMBASE/Cochrane databases for articles examining response to CRT stratified by the presence or not of CR. End-point classified as clinical or echocardiographic response. The analysis compared response to CRT (echocardiographic or clinical) between patients with or without CR.
Results:
824 patients in 12 studies were included. The presence of left ventricular CR was associated with a significant reduction in echocardiographic non-responders to CRT compared to patients without CR (OR: 0.16, 95% CI 0.08-0.33, p<0.00001). The presence of left ventricular CR was associated with a significant reduction in clinical non-responders to CRT compared to patients without CR (OR: 0.23, 95% CI 0.14-0.37, p<0.00001). Sensitivity analysis showed no difference in response when pooling studies using left ventricular ejection fraction (LVEF) or non-LVEF markers of CR. Meta-regression showed that CR was associated with lower rates of non-responders and this was more pronounced in patients with a narrower mean QRS complex.
Conclusions:
Identification of CR is associated with improved response to CRT. Importantly, QRS width is a potential moderator variable which can explain part of the heterogeneity in echo response. The combination of CR and QRS width may modulate the response to CRT.
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