br Conclusion br Conflict of interest br Case

Conclusion
Conflict of interest
Case report He was transferred to our hospital due to cardiopulmonary arrest at age 45. An electrocardiogram revealed ventricular fibrillation, and sinus rhythm was restored by cardiac defibrillation. After intensive therapy, we planned an implantable cardioverter-defibrillator (ICD) implantation. He had normal vital signs (blood pressure: 110/78mmHg; heart rate: 75bpm; O2 saturation: 97% on room air; and body temperature: 36.4°C). Chest X-ray revealed mild cardiomegaly and no pulmonary congestion. The plasma chemical libraries natriuretic peptide level was 300.5pg/mL. An electrocardiogram during sinus rhythm showed signs of left ventricle hypertrophy with a normal QRS duration (QRS duration: 124ms; QTc: 0.435; S wave amplitude in leads V1+R wave amplitude in leads V5=4.92mV). QTc was defined as QT interval/square root of RR interval. Transthoracic echocardiography revealed left ventricular hypertrophy (interventricular septal thickness at end-diastole 14.6mm; left ventricular posterior wall thickness at end-systole 15.0mm; left ventricle mass 221g) with a preserved ejection fraction (left ventricular dimension at end-diastole 39.1mm; left ventricle dimension at end-systole 26.4mm; ejection fraction 61.4%). Oral drug therapy included carvedilol (2.5mg/day), but no antiarrhythmic drugs were taken. An ICD (FORTIFY ST VR; St. Jude Medical, St. Paul, MN, USA) with a single-coil shock lead (DURATA 7122Q-52; St. Jude Medical, St. Paul, MN, USA) was implanted in the right precordium because he had an arteriovenous shunt for dialysis in his left forearm. The defibrillation thresholds (DFTs) were tested. He demonstrated high DFTs (Fig. 1), which were defined as safety margins of less than 10-J between the DFTs and the maximum energy output of the implanted device [1]. The initial defibrillation setting was as follows: waveform, “Biphasic”; waveform mode, “Tilt”; shock configuration, “RV to Can”. Based on the patient׳s high DFTs, we modified the device settings, changing the waveform mode to Pulse Width, but the DFTs did not improve. We then extracted the generator and the lead, and, although the patient had a shunt in his left forearm, we moved the generator to the left precordium and replaced the single-coil shock lead with a dual-coil shock lead (DURATA 7120Q-58; St. Jude Medical, St. Paul, MN, USA) in order to improve the DFTs. Finally, after these changes, we achieved an adequate DFT.
Discussion Predicting high DFTs in patients for whom ICD implantation is planned is important; however, the association between Fabry disease and high DFTs has not been systematically studied. Rhythm and conduction abnormalities have been reported to exist in Fabry disease as a result of the glycosphingolipid storage in cardiomyocytes, conduction system cells, and endothelial cells [2]. As left ventricular hypertrophy is the most common manifestation of Fabry disease, the high DFTs observed in this patient may be attributable to myocardial hypertrophy, which is a well-known substrate of high DFTs [3]. By managing the device settings and using a dual-coil lead, it was possible to implant an ICD with an adequate defibrillation safety margin in this patient with high DFTs. Patients undergoing right-sided ICD implantations have higher DFTs compared with left-sided implants [4].
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Introduction Neurally mediated syncope (NMS) is the most common cause of transient loss of consciousness, and is a clinical condition that reduces the quality of life [1]. Cardioinhibition with asystole or a transitory atrioventricular block induced by a massive vagal reflex is commonly observed in severe cases [2,3]. No proven effective pharmacological therapy exists for the prevention of NMS [4]. Dual-chamber permanent pacing is effective in reducing the occurrence of syncope, but involves permanent device placement [5]. Recently, Pachon et al. reported that endocardial catheter ablation showed excellent long-term results in well-selected NMS patients [6]. In the present case, we report the outcome of a patient with severe NMS associated with significant cardioinhibition who was treated by endocardial ablation with an approach through the superior vena cava (SVC).