Abstract 652: Prevention Of Inappropriate ICD Therapy Due To Supraventricular Tachycardia In Patients With Brugada Syndrome - A Prospective Study
Implantable cardioverter-defibrillators (ICD) are implanted for primary and secondary prevention in patients with Brugada syndrome who are at high risk for sudden cardiac death. It has been reported, that supraventricular tachycardia (SVT) occur in up to 20% of patients diagnosed with Brugada syndrome. Recently it has been shown, that ICD therapy in patients with Brugada syndrome is associated with inappropriate ICD shocks due to SVT in 10–30% of the patients. The aim of this study was to investigate the efficacy and safety of a high VF cut-off rate in order to avoid inappropriate ICD therapies due to SVT.
Patients and methods: Between 2000 and 2007, 40 patients with Brugada syndrome (30 males; mean age 38 ± 13 years) received an ICD for primary (n=36) or secondary (n=4) prevention. All implanted devices were single chamber ICDs (n=25 St. Jude Medical, n=14 Medtronic Inc. and n=1 Guidant). All ICDs were programmed with a single detection zone and a cut-off rate of 222 bpm. A maximum of 6 shocks with the maximal output of the individual device was programmed. ICD interrogations were performed every 3 months.
Results: The patients were followed over a mean time of 45 ± 18 months. All patients survived. Three patients (8%) developed 7 episodes of ventricular fibrillation and received adequate ICD shocks. No patient had syncope during follow-up. One patient (2.5 %) received an inadequate ICD shocks due to T-wave oversensing. One patient (2.5 %) received inappropriate ICD shock due to very fast conducted atrial fibrillation, despite a VF cut-off rate of 222 bpm. In this case, the patient was prescribed oral quinidine and the ICD was programmed to a VF cut-off rate of 231 bpm. Thereafter, no inappropriate ICD shocks occurred.
Conclusions: During a mean follow-up of 3.5 years only 1 patient (2.5 %) received inappropriate ICD shocks due to supraventricular tachycardia. A high VF cut-off rate of 222 bpm lowers the risk of inappropriate ICD shocks significantly. Regarding to the survival of 100 % and the absence of syncope, the high cut-off rate seems to be safe.