Comparison of Outcomes of Catheter Ablation in Asymptomatic Versus Symptomatic Preexcitation to Guidelines and Beyond.

Management of asymptomatic subjects with preexcitation remains controversial. Our objective was to analyze the reasons an electrophysiological study (EPS) was performed in an asymptomatic population referred for the procedure, and compare the results of catheter ablation between asymptomatic and symptomatic patients. Patients ≥18 years of age with preexcitation referred for an EPS and ablation were grouped as either symptomatic or asymptomatic. We analyzed in both subsets for (1) reasons for the procedure, (2) EPS results (anterograde effective refractory period of the accessory pathway, tachycardia/atrial fibrillation inducibility, anatomical localization), (3) success of the procedure, and (4) incidence of complications. We included 175 patients, 121 of which were symptomatic (39 ± 16 years) and 54 were asymptomatic (35 ± 14 years, p = NS not significant). The most frequent symptoms were palpitations (87%) and syncope (7%). EPS was performed in 44 of 54 asymptomatic patients mainly because of involvement in sports (60%) or high-risk employment (14%). Anterograde effective refractory period was significantly longer in asymptomatic patients (314 ± 55 milliseconds) than in symptomatic patients (278 ± 46 milliseconds; p <0.001). Orthodromic tachycardia inducibility was significantly higher in symptomatic than in asymptomatic patients (69% and 27%, respectively; p <0.001). A total of 170 accessory pathways (49% left free wall, 12% right free wall, 39% septal) were observed without significant differences in the anatomical location between groups. Catheter ablation was attempted in all patients, succeeding in 98% of symptomatic and 95% of asymptomatic patients, without major complications in either group. In conclusion, the reasons for invasive evaluation of asymptomatic patients with preexcitation may be outside the scope of current guidelines. Catheter ablation produces excellent results without major complications.

Manifest preexcitation with a prolonged PR interval: What is the mechanism?

A 44-year-old woman with a past history of surgical ablation of an accessory pathway presented to our facility with episodes of palpitations and dizziness. An ECG showed sinus rhythm with a prolonged PR interval and a preexcited QRS complex. An EP study revealed AV conduction through a postero-septal accessory pathway and a prolonged PR interval due to severe intra-atrial conduction delay.

An "inappropriately appropriate" shock in a subcutaneous implantable cardioverter-defibrillator: The importance of the SMART pass algorithm.

We report on a case of a 78-years-old patient with a subcutaneous implantable cardioverter defibrillator (S-ICD) and an episode of a sustained ventricular tachycardia (VT) at a rate slower than the programmed shock zone. Because of T-wave oversensing the device interpreted it as fast VT that triggered the delivery of an "inappropriately appropriate shock" that terminated it. The patient had again more VT episodes but after programming the SMART pass algorithm (previously programmed "OFF") the device showed no longer frequent T-wave oversensing and no additional inappropriate shocks occurred.