Role of Strauss ECG criteria as predictor of response in patients undergoing cardiac resynchronization therapy

Abstract Background Cardiac resynchronization therapy( CRT) is a standard treatment in patients with heart failure, however, approximately 20–40% of recipients of (CRT) do not respond to it based on the current patients’ election criteria. The purpose of this study was to identify the baseline parameters that predict the CRT response and how the ECG morphology can affect the outcome. Objective To evaluate the Strauss ECG criteria as predictor of response in patients undergoing Cardiac resynchronization therapy. Material and Methods From March 2020 to March 2022, 70 patients underwent CRT or CRT-D insertion with LBBB morphology in Ain Shams university hospitals, Cardiology department were enrolled in the study. All patients subjected to history, clinical examination, Electrocardiogram and echocardiography before CRT insertion and after 6 months. We analyzed the QRS morphology of the patients with LBBB-like pattern as we classified patients in two groups, Strauss LBBB criteria (SLBBB) which was (a QRS duration of < 140 ms for men and <130 ms for women, along with mid-QRS notching or slurring in at least 2 of the leads V1, V2, V5, V6, I, or aVL and also rS or QS morphology in lead V1 patients) and the other group that was not meeting the previous criteria as non-strauss LBBB (non-SLBBB), also all patients subjected to echocardiography ( conventional 2D and speckle tracking “global longitudinal strain and global circumferential strain), Ejection fraction was assessed together with LV volumes and speckle tracking to assess response to CRT. Results Out of 70 patients, 3 patients missed the 6 months follow up after CRT implantation, so the study enrolled 67 patients that have been classified according to ECG morphology of LBBB to 37 patients with non-Strauss ECG criteria- one of whom died after 4 months- and 30 patients with Strauss ECG criteria. The number of responders in the study was 50 patients with percentage 75.8%, 52% of CRT responder (26 patients) had non Strauss ECG criteria while 48% of CRT responders (24 patients) had Strauss ECG criteria with P value=0.463. While there was no statistical significance of overall CRT response nor 6 months hospitalization and mortality between patients of Strauss and non-Strauss ECG criteria, there was a significant improvement in NYHA class, EF assessed by biplane Simpson’s, End- systolic volume, Global longitudinal strain and Global circumferential strain by speckle tracking echocardiography in patients with Strauss ECG criteria of LBBB. Conclusion There is no statistical significance in overall CRT response nor the 6 months hospitalization and mortality after 6 months of follow up between patients with Strauss and non-Strauss ECG criteria of LBBB, however, patients with Strauss ECG criteria have better improvement in NYHA class, echocardiographic parameters such as EF and ESV and speckle tracking parameters (GLS and GCS).