Po-05-018 giant intraseptal hematoma complicating left bundle branch pacing: an unusual clinical challenge

Left bundle branch pacing (LBBP) is an excellent alternative to His bundle pacing (HBP). Due to its non-traditional intraseptal lead placement, rare but unusual complications have been described. We present the case of a unique complication of a very large septal hematoma following LBBP. n/a An 88-year-old female with Coronary disease, renal insufficiency, and uncontrolled atrial fibrillation was referred for AV node ablation and conduction system pacing. Due to high HBP thresholds, a LBBP lead was implanted in proximal location (Stim-V6 peak=70ms, QRSd=135ms) with a backup second LBBP lead at a slightly distal location (Stim-V6 peak=61ms, QRSd=121ms) with low capture thresholds. She was discharged home the same day. She was readmitted a-day later with nausea, weakness, and significant dyspnea. Echocardiogram revealed a very large septal hematoma (61mm x 40mm) with complete obliteration of right ventricle cavity and no pericardial effusion (Figure 1A). IV fluid bolus was given, and Apixaban/Clopidogrel/ASA were held. Angiography and possible embolization of bleeding septal perforator was considered but not performed due to her CKD and hemodynamic stability. Serial echo revealed improved RV filling, stable hematoma and absent effusion. She was discharged on day 7 in stable condition. Anticoagulation was resumed after 2 weeks. Repeat echo at 6 weeks showed complete resolution of interventricular septal hematoma and lead parameters were stable (Figure 1B). This is a unique and rare case of a giant interventricular septal hematoma post LBBP, successfully managed with conservative management. Given rarity of complication, maintaining a broad differential for early recognition and treatment remains paramount. Avoiding a very proximal and anterior left bundle area, if possible, can be considered to avoid a major septal perforator. Repeat imaging and close hemodynamic monitoring is recommended in such patients. Angiography to localize the bleeding septal perforator and possible embolization may be considered for hemodynamic instability. This was deferred in our patient due to severe renal insufficiency, as well as lack of pericardial effusion and improving hemodynamics not requiring inotropic support. However, we recommend a multidisciplinary heart team and critical care approach, as was used in this case, to help personalize management.