- Email: [email protected]
A CASE OF DEFIBRILLATION THRESHOLD TESTING FAILURE WITH SUBCUTANEOUS IMPLANTABLE DEFIBRILLATOR IMPLANTATION IN A HYPERTROPHIC CARDIOMYOPATHY PATIENT
2294 JACC March 21, 2017 Volume 69, Issue 11
FIT Clinical Decision Making A CASE OF DEFIBRILLATION THRESHOLD TESTING FAILURE WITH SUBCUTANEOUS IMPLANTABLE DEFIBRILLATOR IMPLANTATION IN A HYPERTROPHIC CARDIOMYOPATHY PATIENT Poster Contributions Poster Hall, Hall C Saturday, March 18, 2017, 9:45 a.m.-10:30 a.m. Session Title: FIT Clinical Decision‐Making: Arrhythmias and Electrophysiology Abstract Category: Arrhythmias and Clinical EP Presentation Number: 1206-382 Authors: Sonia Samtani, Hiro Kawata, Govind Rajan, Matthew Dolich, Anjan Batra, Teferi Mitiku, University of California, Irvine, Orange, CA, USA
Background: The subcutaneous implantable defibrillators (S-ICD) were designed to avert risks associated with transvenous leads, which is often seen in the younger population including those suffering from hypertrophic cardiomyopathy (HCM).
Case: A 14-year-old male with HCM and morbid obesity underwent exercise echocardiogram, which showed a markedly increased Left Ventricle Outflow Tract gradient at submaximal exercise associated with hypotension. He underwent consideration for S-ICD implantation. During implantation, defibrillation threshold testing (DFT) was conducted. The patient went into Ventricular Fibrillation (VF). The S-ICD delivered an 80J shock but failed. External rescue defibrillation at 200J was attempted without success. Three different machines were used simultaneously with a total shock of 600J but still failed. CPR had been initiated within 1 minute of the VF. Emergent lateral thoracotomy was conducted with intracardiac massage for one minute. Internal defibrillator paddles of 50J were initially used but only after 100J was administered did the arrhythmia terminate. The S-ICD was returned to Boston Scientific where the pulse generator lead, and software were found to function normally. Decision‐Making: This case demonstrated several clinical concerns, including the efficacy of S-ICDs within the HCM population, and the necessity of DFT. S-ICD represents an exciting option in ICD therapy given that the lead is placed in the subcutaneous layer of the thoracic cage, which avoids potential complications related to wear of transvenous leads. DFT in HCM may be higher than in other cardiomyopathies and may increase over time. It has also been noted that QRS and T wave over-sensing may be more common in hypertrophic cardiomyopathy. In transvenous ICD systems, body habitus is not a predictor for high DFT, since the lead touches the endocardium. Our patient underwent dual coil transvenous ICD implantation 5 days after his initial S-ICD implantation.
Conclusions: HCM is a diverse and unpredictable disease, thus it is recommended that those patients undergoing ICD implantation for primary prevention be screened carefully for various factors that impact the DFT.
FIT Clinical Decision Making A CASE OF DEFIBRILLATION THRESHOLD TESTING FAILURE WITH SUBCUTANEOUS IMPLANTABLE DEFIBRILLATOR IMPLANTATION IN A HYPERTROPHIC CARDIOMYOPATHY PATIENT Poster Contributions Poster Hall, Hall C Saturday, March 18, 2017, 9:45 a.m.-10:30 a.m. Session Title: FIT Clinical Decision‐Making: Arrhythmias and Electrophysiology Abstract Category: Arrhythmias and Clinical EP Presentation Number: 1206-382 Authors: Sonia Samtani, Hiro Kawata, Govind Rajan, Matthew Dolich, Anjan Batra, Teferi Mitiku, University of California, Irvine, Orange, CA, USA
Background: The subcutaneous implantable defibrillators (S-ICD) were designed to avert risks associated with transvenous leads, which is often seen in the younger population including those suffering from hypertrophic cardiomyopathy (HCM).
Case: A 14-year-old male with HCM and morbid obesity underwent exercise echocardiogram, which showed a markedly increased Left Ventricle Outflow Tract gradient at submaximal exercise associated with hypotension. He underwent consideration for S-ICD implantation. During implantation, defibrillation threshold testing (DFT) was conducted. The patient went into Ventricular Fibrillation (VF). The S-ICD delivered an 80J shock but failed. External rescue defibrillation at 200J was attempted without success. Three different machines were used simultaneously with a total shock of 600J but still failed. CPR had been initiated within 1 minute of the VF. Emergent lateral thoracotomy was conducted with intracardiac massage for one minute. Internal defibrillator paddles of 50J were initially used but only after 100J was administered did the arrhythmia terminate. The S-ICD was returned to Boston Scientific where the pulse generator lead, and software were found to function normally. Decision‐Making: This case demonstrated several clinical concerns, including the efficacy of S-ICDs within the HCM population, and the necessity of DFT. S-ICD represents an exciting option in ICD therapy given that the lead is placed in the subcutaneous layer of the thoracic cage, which avoids potential complications related to wear of transvenous leads. DFT in HCM may be higher than in other cardiomyopathies and may increase over time. It has also been noted that QRS and T wave over-sensing may be more common in hypertrophic cardiomyopathy. In transvenous ICD systems, body habitus is not a predictor for high DFT, since the lead touches the endocardium. Our patient underwent dual coil transvenous ICD implantation 5 days after his initial S-ICD implantation.
Conclusions: HCM is a diverse and unpredictable disease, thus it is recommended that those patients undergoing ICD implantation for primary prevention be screened carefully for various factors that impact the DFT.