Inappropriate Shocks After Mitraclip Placement: Should Reassessment of Post-Procedural ICD Sensitivity Be Routine Practice?

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Case Description: A 53 year old African American woman with non-ischemic cardiomyopathy (EF 10%) with intolerance to GDMT (allergies) and severe secondary MR. An ICD was placed years ago. Given LBBB and QRS 146ms, she underwent a BiV(biventricular pacing)-ICD upgrade with symptomatic improvement, but persisting exertional intolerance. TEE showed a favorable anatomic profile for transcatheter edge-to-edge MV repair and a MitraClip™ was placed. Post-procedure, the severity of MR decreased significantly (from severe to mild), however there was no sizable improvement in LV EF. Also, there were no significant EKG changes. Three months later, she experienced multiple inappropriate shocks (IAS). Device interrogation revealed T-wave oversensing (TWOS). TWOS was noted on multiple vectors with LV only pacing, but was solely associated with fusion complexes on BiV pacing. R wave sensing threshold was increased. Patient was switched to BiV only pacing and AV delay(paced and sensed) was decreased to avoid fusion beats. Patient did well and no further IAS were noted at 4 months follow-up.

Discussion: ICDs (+/- CRT) are vital in preventing SCD in advanced CHF. Currently, transvenous technology is excellent at avoiding TWOS, however our case represents a challenging dilemma where repolarization may have changed post-operatively after MitraClip™ placement. T wave amplitude is dynamic and real time monitoring of sensing threshold is needed. This becomes especially important after structural heart procedures like MV TEER that can induce subclinical electroanatomic changes. While MitraClip™ can reduce ventricular arrhythmias with favorable remodeling, inappropriate sensing of devices is a small but real risk. Consequently, there are no established guidelines on routine post-procedural device interrogation. Preemptive reassessment of T wave safety margin and monitoring of sensing thresholds and lead placement may be useful following structural heart interventions.




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American Heart Association Scientific Sessions, November 11-13, 2023, Philadelphia, PA