Global Myocardial Work Index Predicts Response to Biventricular Pacing in Patients with Non-Left Bundle Branch Block

Figure 1. (A) Example of the estimated LV pressure curve (left upper) and the corresponding LV strain trace (left lower). The estimated LV pressure curve was adjusted according to the opening and closing timing of the aortic and mitral valves and non‐invasive systolic blood pressure obtained using a brachial artery sphygmomanometer. Based on these data, the LV pressure–strain loop was automatically created (right). (B) Representative case with the response to CRT. The LV pressure–strain loop (left) and bull's‐eye images of GWI (right) before (upper) and 6 months after CRT (lower). The baseline GWI was 1153 mmHg%, which was higher than the cut‐off value of 456 mmHg% for responders in our study. After 6 months of CRT, the GWI increased from 1153 mmHg% to 1729 mmHg%. AVC, aortic valve; AVO, aortic valve opening; CRT, cardiac resynchronization therapy; GWI, global work index; LV, left ventricular; MVC, mitral valve closure; MVO, mitral valve opening.

Figure 2. Flowchart diagram of patient selection. AVB, atrioventricular block; CRT, cardiac resynchronization therapy; LBBB, left bundle branch block; NICD, non‐specific intraventricular conduction delay; RBBB, right bundle branch block; RVP, right ventricular pacing.

Figure 3. ROC curve analysis of GWI for the response to CRT. AUC, area under the curve; CI, confidence interval; CRT, cardiac resynchronization therapy; GWI, global work index; ROC, receiver operating characteristic.

Figure 4. Kaplan–Meier survival curves. (A) all‐cause death, (B) cardiac death, (C) HF hospitalization, and (D) composite event (death or HF hospitalization) according to the GWI cut‐off of 456 mmHg% at baseline. GWI, global work index; HF, heart failure.