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Published on: December 11, 2017
QRS Area Before and After Upgrading to Cardiac Resynchronization Therapy Is Not Sufficient to Predict Outcome
Fenna Daniëls1, Frederieke Eerenberg2, Mariëlle Kloosterman1
1Department of Cardiology, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands.
QRS area, a measure of ventricular electrical dyssynchrony, did not predict the primary outcome in patients upgraded to cardiac resynchronization therapy (CRT). However, higher baseline QRS area correlated with better echocardiographic response, and a significant change in QRS area was linked to fewer heart failure hospitalizations.
Area of Science:
- Cardiology
- Electrophysiology
- Heart Failure Management
Background:
- QRS area is a key indicator of ventricular electrical dyssynchrony.
- Its predictive value for cardiac resynchronization therapy (CRT) outcomes surpasses QRS duration/morphology.
- Limited data exists on QRS area in patients upgraded from right ventricular pacing to CRT.
Purpose of the Study:
- To evaluate the association between QRS area and the difference in biventricular paced QRS area (ΔQRS) with clinical outcomes and echocardiographic response in CRT-upgraded patients.
- To determine if baseline QRS area and ΔQRS area predict mortality, heart transplantation, left ventricular assist device implantation, heart failure hospitalization (HFH), and echocardiographic response.
- To investigate the clinical significance of QRS area changes following CRT upgrade.
Main Methods:
- Retrospective multicenter study including 303 patients upgraded to CRT.
- Median values of baseline QRS area and ΔQRS area were used as cut-offs.
- Primary outcome: all-cause mortality, heart transplantation, or LVAD. Secondary outcomes: HFH and ≥15% reduction in LV end-systolic volume.
Main Results:
- The primary composite outcome occurred in 34.3% of patients, with no significant difference based on baseline or ΔQRS area.
- Patients with a large ΔQRS area (≥35 µVs) experienced fewer HFHs (6.7% vs. 15.4%, p=0.012).
- Baseline QRS area >132 µVs was associated with improved echocardiographic response (OR 2.23, p=0.026) but not HFH (p=0.832). ΔQRS area >35 µVs was not linked to echocardiographic response (p=0.203).
Conclusions:
- QRS area and ΔQRS area were not associated with the primary composite outcome in CRT-upgraded patients.
- Baseline QRS area >132 µVs may predict better echocardiographic response to CRT.
- A larger ΔQRS area (≥35 µVs) might be associated with a reduced risk of heart failure hospitalization.
