For the relationship between the PVAB and FFRWs setting
For the relationship between the PVAB and FFRWs, setting the PVAB period as short as possible is considered optimal, because not all patients necessarily have problems with FFRWs [4,6]. However, the Medtronic pacemakers investigated in this study had minimum PVAB values as short as 110ms or 130ms, which are much longer than those of the other manufacturer\'s products (60ms for the St. Jude Medical and 30ms for the Guidant products). Therefore, too long a PVAB value prevents the determination of a correct automated arrhythmia diagnosis in cases with a relatively early timing for FFRWs or in cases with small FFRW amplitude compared with atrial potentials (Fig. 5). As for programmable PVAB value, the lower limit of the programmability of the PVAB value should be much smaller. Despite all the attempts to adjust the PVAB value, there are still cases of simultaneous atrial and ventricular activations and this limits the effectiveness of a pacemaker\'s automated tachyarrhythmia diagnosis (Fig. 8A and B).
Limitations The following cases may not be suitable for AEGM follow-up (in such instances, EGM selection should be made on a case-by-case basis):
Introduction Brugada syndrome is characterized by ST-segment elevation in the right precordial leads and sudden cardiac death (SCD) . In general, the mean age of victims of SCD is approximately 40 years . Brugada syndrome is believed to account for 4–12% of all cardiac deaths and at least 20% of deaths in patients with a structurally normal heart . Thus, the timely diagnosis of Brugada syndrome is clinically imperative. However, myocardial ischemia can cause right ventricular ST-segment elevation similar to the Brugada ECG pattern [3–7], and the coexistence of Brugada syndrome with vasospastic LY 2157299 has been reported [8–12]. In addition, Brugada syndrome has been reported to associate with individual cases of significant coronary artery stenosis [13–17]. Thus, Brugada syndrome cannot be diagnosed simply on the basis of standard guidelines if such potential confounding factors are present [2,7]. The present retrospective study was undertaken to evaluate the coexistence of Brugada syndrome and coronary artery disease in a single center.
Materials and methods
Results The male/female sex ratio in the study group was 53/2, and the mean age was 50.4±13.8 years (range, 24–79 years). Brugada syndrome ECG patterns were spontaneous type 1 (n=31) and drug-induced type 1 (n=24; type 2=14, type 3=10). The clinical, genetic, electrocardiographic, and electrophysiological characteristics of the study patients are shown in Table 1. Eleven patients were symptomatic (3 with history of syncope, 2 with presyncope, and 6 with aborted SCD), and 5 patients had a positive family history of SCD. An SCN5A gene mutation was found in 2 patients (5.4%). The left ventriculogram was normal with an ejection fraction of 69.2%±9.0% (55–89%) in 55 patients who had undergone left ventricular angiography. The coronary angiogram, although normal in 49 patients, revealed significant coronary artery disease in 5 patients. Risk factors in patients with coronary artery disease are listed in Table 2. Patients with coronary artery disease were older than those without coronary artery disease (59.4±7.2 years vs. 49.0±13.8 years, P=0.03) (Table 1). Two of the 5 patients (Patients 2 and 4) exhibited symptoms related to coronary artery disease. PVS was performed in 50 patients without significant coronary artery stenosis and in 4 of the 5 patients with coronary artery disease, which induced VF/polymorphic ventricular tachycardia (PVT) in 45 of the 50 patients (90%) without coronary artery disease and in the 4 patients with coronary artery disease (Table 2). Details regarding the electrophysiological data and the coronary angiogram are provided in Table 3. An ICD was implanted in 19 patients who had inducible PVT/VF and desired an ICD implant (38.8%). Two representative cases of coronary artery disease are described below.