Furthermore the normalization sequence of J waves

Furthermore, the normalization sequence of J waves and the ST segment suggests that J waves are more sensitive to ischemia. In fact, J waves were observed before ST-segment elevation when coronary spasms were induced in a provocation test [8,18]. However, the pathogenesis of ischemia-induced J waves is to be further elucidated.
Conclusions
Introduction Micturition syncope is classified as situational syncope—a type of neurally mediated syncope (NMS). In this condition, a cardiopulmonary receptor and left ventricular mechanoreceptor is abnormally activated with decreased left ventricular dimensions, resulting in inappropriate peripheral blood pooling, blood pressure decrease, and bradycardia [1]. The effect of cardiac pacing therapy for NMS remains controversial because pacing therapy does not alter peripheral vasodilatation or prevent the occurrence of a reflex response [2,3]. Pacing therapy was not effective in a mixed group of NMS patients who were relatively young [1]. In contrast, a randomized trial showed that a DDD pacemaker with a rate-drop response function is more effective than the β-blocker treatment for recurrent vasovagal syncope [4]. A pacemaker with a closed-loop stimulation (CLS) function monitors myocardial contractile dynamics and translates intrinsic inotropic information into pacing rates. Occhetta et al. showed that CLS function is useful for the prevention of vasovagal syncope [5]. Kanjwal et al. demonstrated the effectiveness of the CLS function for the prevention of neurocardiogenic syncope as compared with the rate-drop or rate-hysteresis response [6]. The CLS function has long been used for the prevention of recurrent vasovagal syncope episodes [5,7]. However, the mechanism of how the CLS function prevents micturition syncope is not clear. We report a patient with micturition syncope in whom syncopal episodes could be prevented because of increased EZ Cap Reagent GG (3\' OMe) rates (HRs) caused by atrial pacing using the CLS function.
Case report A 70-year-old man had been experiencing syncope approximately 3 times per year since 2006. These episodes generally occurred after micturition at midnight, after excess consumption of alcohol, after bathing, or during activities such as pruning. He had been advised to refrain from alcohol for approximately 3 years. In 2009, he was brought to our hospital because of a syncope episode that occurred after watching a bonfire. He experienced nausea and a cold sweat before the syncope. Holter electrocardiography (ECG) revealed an average HR of 53bpm, a maximum sinus arrest of 2.4s, and frequent sinoatrial block episodes. Electrophysiological assessment revealed a corrected sinus node recovery time of 778ms and a calculated sinoatrial conduction time of 223ms, indicating a mild sinus-node dysfunction. Although syncope was not elicited by an isoproterenol-infusion head-up tilt test or a carotid sinus massage test, his syncopal episodes suggested situational syncope. Therefore, we implanted a DDD pacemaker with a CLS function (basal rate of 50ppm and a resting rate control of +20ppm) after he provided informed consent. Variations in HR and blood pressure (BP) were monitored during micturition during the day in both the DDD-R and DDD-CLS modes. In DDD-CLS, an increased atrial pacing ratio (79.3%) maintained his HR at approximately 70bpm during and after micturition (Fig. 1). In contrast, his intrinsic HR decreased from 67bpm to approximately 60bpm after micturition, but atrial pacing was not observed in the DDD-R mode. His systolic BP decreased by approximately 20mm Hg after micturition in both the DDD-CLS and DDD-R modes, but his systolic BP recovered within 1–2min; syncope did not occur in either mode. Holter ECG monitoring was performed after the patient consumed 180mL of sake (alcohol) each night in both the DDD-R and DDD-CLS modes. The mean HR in the DDD-CLS mode (68bpm) was similar to that (71bpm) in the DDD-R mode, but during sleep, the atrial pacing ratio (43.2%) in DDD-CLS was significantly higher than that (7.4%) in the DDD-R mode (p<0.001). The patient\'s condition was checked in each of the DDD-CLS and DDD-R modes during early morning urination. In the DDD-CLS mode, increased atrial pacing rates maintained his HR at a higher rate during and after micturition, and he had no symptoms (Fig. 2A). In the DDD-R mode, he experienced a sense of cold perspiration and presyncope after micturition. His intrinsic HR changed to atrial pacing after micturition but soon decreased to the basal rate (50ppm) (Fig. 2B). Although we did not measure BP, we assume that, in the DDD-R mode, his BP and intrinsic HR might have decreased after micturition. Therefore, we implanted the DDD-CLS pacemaker. After implantation, the patient has not experienced syncope episodes for 40 months.
Discussion Micturition syncope is a daily excretion-related transient circulatory disorder and is classified as situational syncope. Sumiyoshi et al. showed that in the elderly, micturition syncope commonly occurred early in the morning or after alcohol consumption at midnight. They also showed that the rate of positive response to the head-up tilt test was low, and premonitory symptoms before syncope were rare [8,9]. No syncope was observed in our patient during the isoproterenol-infusion head-up tilt test. Syncope did not occur after micturition in either of the DDD-R and DDD-CLS modes during the day, but the patient experienced a sense of presyncope in the DDD-R mode after alcohol consumption and after micturition early in the morning.