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A novel electrocardiographic predictor of clinical response to cardiac resynchronization therapy
Roberto Mollo1, Alessandro Cosenza, Ilaria Coviello
1Istituto di Cardiologia, Università Cattolica del Sacro Cuore, Largo A. Gemelli, 8, Rome 00168, Italy.
Insights
Detailed QRS analysis, specifically the R-wave peak to S-wave nadir interval in lead V1 (RS-V1), can predict cardiac resynchronization therapy (CRT) success in dilated cardiomyopathy patients. An RS-V1 duration of ≥45 ms or a reduction of ≥10 ms post-CRT indicates a higher likelihood of positive response.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Diagnostics
Background:
- Cardiac resynchronization therapy (CRT) is indicated for heart failure patients with dilated cardiomyopathy and a wide QRS complex, typically with a left bundle branch block pattern.
- However, a significant portion of patients (approximately 30%) do not achieve a beneficial response to CRT, necessitating improved patient selection strategies.
Purpose of the Study:
- To investigate whether detailed electrocardiogram (ECG) analysis of the QRS complex, beyond standard criteria, can enhance the prediction of CRT response in patients with dilated cardiomyopathy.
- To identify specific QRS parameters that correlate with successful CRT outcomes.
Main Methods:
- A cohort of 51 patients with dilated cardiomyopathy indicated for CRT underwent detailed ECG analysis before and 3 months after therapy.
- Key ECG intervals, including the R-wave peak to S-wave nadir in V1 (RS-V1) and V6, were meticulously measured.
- CRT responders were defined by a ≥5% increase in left ventricular ejection fraction (LVEF) and a ≥1 class improvement in New York Heart Association (NYHA) functional class.
Main Results:
- The basal RS-V1 interval was significantly longer in CRT responders (52.9 ± 11.8 ms) compared to non-responders (44.0 ± 12.6 ms) (P = 0.021).
- Patients with a basal RS-V1 ≥ 45 ms demonstrated an 83% response rate to CRT, versus 33% in those with RS-V1 < 45 ms (P < 0.001).
- A reduction in RS-V1 by ≥ 10 ms after CRT also significantly predicted clinical response and correlated with improvements in LVEF and NYHA class.
Conclusions:
- The RS-V1 interval, both at baseline and its change following CRT, serves as a valuable predictor for identifying patients likely to benefit from CRT.
- This detailed ECG analysis offers a non-invasive method to optimize patient selection for CRT, potentially improving therapeutic efficacy.
Aims:
A wide QRS with left bundle branch block pattern is usually required for cardiac resynchronization therapy (CRT) in patients with dilated cardiomyopathy. However, ∼30% of patients do not benefit from CRT. We evaluated whether a detailed analysis of QRS complex can improve prediction of CRT success.
Methods And Results:
We studied 51 patients (67.3 + 9.5 years, 36 males) with classical indication to CRT. Twelve-lead electrocardiogram (ECG) (50 mm/s, 0.05 mV/mm) was obtained before and 3 months after CRT. The following ECG intervals were measured in leads V1 and V6: (i) total QRS duration; (ii) QRS onset-R wave peak; (iii) R wave peak-S wave peak (RS-V1 and RS-V6); (iv) S wave peak-QRS end; and (v) difference between QR in V6 and in V1. Patients were considered as responder when left ventricular ejection fraction (LVEF) increased by ≥5% and New York Heart Association class by ≥1 after 3 months of CRT. Of ECG intervals, only basal RS-V1 was longer in responders (n = 36) compared with non-responders (52.9 ± 11.8 vs. 44.0 ± 12.6 ms, P = 0.021). Among patients with RS-V1 ≥45 ms 83% responded to CRT vs. 33% of those with RS-V1 < 45 ms (P < 0.001). RS-V1 ≥ 45 ms was independently associated with response to CRT in multivariable analysis (odds ratio 9.8; P = 0.002). A reduction of RS-V1 ≥ 10 ms by CRT also significantly predicted clinical response. RS-V1 shortening correlated with improvement in LVEF (r = -0.45; P < 0.001) and in MS (r = 0.46; P < 0.001).
Conclusion:
Our data point out that RS-V1 interval and its changes with CRT may help to identify patients who are most likely to benefit from CRT.
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