Device-based Optimization of Cardiac Resynchronization—One Size Does Not Fit All

Wasim Rashid, Asim Kichloo, Khalil Kanjwal

Research output: Contribution to journalArticlepeer-review


We report on a 72-year-old female patient who was sent to our clinic for evaluation of a biventricular intracardiac defibrillator (BIV-ICD). The patient was diagnosed with ischemic cardiomyopathy and showed a persistently low ejection fraction in the range of 20%–25% with New York Heart Association class III heart failure symptoms despite being on guideline-directed medical therapy, including a β-blocker and a combination of sacubitril and valsartan, for >3 months. In addition, the patient had underlying right bundle branch block (RBBB) with a QRS duration of 160 ms. The device was programmed with a Sync-AV algorithm on with nominal settings (delta of −50 ms). The thresholds and lead impedances were acceptable. Electrocardiography was performed in the postoperative period, showing persistent RBBB similar to the baseline electrocardiogram without much QRS narrowing. In this report, we discuss the mechanism and troubleshooting of this problem.

Original languageEnglish
Pages (from-to)4936-4940
Number of pages5
JournalJournal of Innovations in Cardiac Rhythm Management
Issue number3
StatePublished - Mar 2022


  • Cardiac resynchronization therapy
  • Sync-AV
  • cardiomyopathy
  • defibrillator
  • right bundle branch block


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