Shengjie Wu

Benefits of Permanent His Bundle Pacing Combined With Atrioventricular Node Ablation in Atrial Fibrillation Patients With Heart Failure With Both Preserved and Reduced Left Ventricular Ejection Fraction

Background Clinical benefits from His bundle pacing (HBP) in heart failure patients with preserved and reduced left ventricular ejection fraction are still inconclusive. This study evaluated clinical outcomes of permanent HBP in atrial fibrillation patients with narrow QRS who underwent atrioventricular node ablation for heart failure symptoms despite rate control by medication. Methods and Results The study enrolled 52 consecutive heart failure patients who underwent attempted atrioventricular node ablation and HBP for symptomatic atrial fibrillation. Echocardiographic left ventricular ejection fraction and left ventricular end‐diastolic dimension, New York Heart Association classification and use of diuretics for heart failure were assessed during follow‐up visits after permanent HBP. Of 52 patients, 42 patients (80.8%) received permanent HBP and atrioventricular node ablation with a median 20‐month follow‐up. There was no significant change between native and paced QRS duration (107.1±25.8 versus 105.3±23.9 milliseconds, P=0.07). Left ventricular end‐diastolic dimension decreased from the baseline (P<0.001), and left ventricular ejection fraction increased from baseline (P<0.001) in patients with a greater improvement in heart failure with reduced ejection fraction patients (N=20) than in heart failure with preserved ejection fraction patients (N=22). New York Heart Association classification improved from a baseline 2.9±0.6 to 1.4±0.4 after HBP in heart failure with reduced ejection fraction patients and from a baseline 2.7±0.6 to 1.4±0.5 after HBP in heart failure with preserved ejection fraction patients. After 1 year of HBP, the numbers of patients who used diuretics for heart failure decreased significantly (P<0.001) when compared to the baseline diuretics use. Conclusions Permanent HBP post–atrioventricular node ablation significantly improved echocardiographic measurements and New York Heart Association classification and reduced diuretics use for heart failure management in atrial fibrillation patients with narrow QRS who suffered from heart failure with preserved or reduced ejection fraction.

MicroRNA‐21 protects against cardiac hypoxia/reoxygenation injury by inhibiting excessive autophagy in H9c2 cells via the Akt/mTOR pathway

MicroRNAs and autophagy play critical roles in cardiac hypoxia/reoxygenation (H/R)‐induced injury. Here, we investigated the function of miR‐21 in regulating autophagy and identified the potential molecular mechanisms involved. To determine the role of miR‐21 in regulating autophagy, H9c2 cells were divided into the following six groups: control group, H/R group, (miR‐21+ H/R) group, (miR‐21‐negative control + H/R) group, (BEZ235+ H/R) group and (miR‐21+ BEZ235+ H/R) group. The cells underwent hypoxia for 1 hr and reoxygenation for 3 hrs. Cell count kit‐8 was used to evaluate cell function and apoptosis was analysed by Western blotting. Western blotting and transmission electron microscopy were used to investigate autophagy. We found that miR‐21 expression was down‐regulated, and autophagy was remarkably increased in H9c2 cells during H/R injury. Overexpression of miR‐21 with a miR‐21 precursor significantly inhibited autophagic activity and decreased apoptosis, accompanied by the activation of the AKT/mTOR pathway. In addition, treatment with BEZ235, a novel dual Akt/mTOR inhibitor, resulted in a significant increase in autophagy and apoptosis. However, we found that miR‐21‐mediated inhibition of apoptosis and autophagy was partly independent of Akt/mTOR activation, as demonstrated in cells treated with both miR‐21 and BEZ235. We showed that miR‐21 could inhibit H/R‐induced autophagy and apoptosis, which may be at least partially mediated by the Akt/mTOR signalling pathway.

A Novel Pacing Strategy With Low and Stable Output: Pacing the Left Bundle Branch Immediately Beyond the Conduction Block

This report demonstrates the feasibility of pacing the left bundle branch (LBB) immediately beyond the conduction block to functionally restore the impaired His-Purkinje conduction system in a patient with heart failure and left bundle branch block (LBBB). The pacing required only a low pacing output (0.5 volts/0.5 ms) to correct the LBBB with accompanying right BBB on the electrocardiogram. Over 1-year of follow-up, the patient had a significant improvement in clinical outcome and echocardiographic measurements. The case shows a novel pacing strategy for patients with BBB that affects many patients with heart failure.

Long-term outcomes of His bundle pacing in patients with heart failure with left bundle branch block

Objectives His bundle pacing (HBP) can potentially correct left bundle branch block (LBBB). We aimed to assess the efficacy of HBP to correct LBBB and long-term clinical outcomes with HBP in patients with heart failure (HF). Methods This is an observational study of patients with HF with typical LBBB who were indicated for pacing therapy and were consecutively enrolled from one centre. Permanent HBP leads were implanted if the LBBB correction threshold was <3.5V/0.5 ms or 3.0 V/1.0 ms. Pacing parameters, left ventricular ejection fraction (LVEF), left ventricular end-systolic volume (LVESV) and New York Heart Association (NYHA) Class were assessed during follow-up. Results In 74 enrolled patients (69.6±9.2 years and 43 men), LBBB correction was acutely achieved in 72 (97.3%) patients, and 56 (75.7%) patients received permanent HBP (pHBP) while 18 patients did not receive permanent HBP (non-permanent HBP), due to no LBBB correction (n=2), high LBBB correction thresholds (n=10) and fixation failure (n=6). The median follow-up period of pHBP was 37.1 (range 15.0–48.7) months. Thirty patients with pHBP had completed 3-year follow-up, with LVEF increased from baseline 32.4±8.9% to 55.9±10.7% (p<0.001), LVESV decreased from a baseline of 137.9±64.1 mL to 52.4±32.6 mL (p<0.001) and NYHA Class improvement from baseline 2.73±0.58 to 1.03±0.18 (p<0.001). LBBB correction threshold remained stable with acute threshold of 2.13±1.19 V/0.5 ms to 2.29±0.92 V/0.5 ms at 3-year follow-up (p>0.05). Conclusions pHBP improved LVEF, LVESV and NYHA Class in patients with HF with typical LBBB.

Pacing Treatment of Atrial Fibrillation Patients with Heart Failure: His Bundle Pacing Combined with Atrioventricular Node Ablation

As an alternative to antiarrhythmic drugs and catheter ablation of atrial fibrillation (AF) for rate and rhythm control, pacing combined with atrioventricular node (AVN) ablation is suitable for many AF patients with heart failure (HF) who suffer from symptoms despite optimal medical therapy or have failed AF ablation. Studies have demonstrated His bundle pacing in conjunction with AVN ablation to treat refractory AF patients with HF provide long-term clinical benefits. Here we introduce the clinical application and procedures of His bundle pacing and AVN ablation.