Management of Sudden Cardiac Death (SCD) is undergoing a radical change in direction. It is becoming increasingly appreciated that besides depressed left ventricular systolic function and the conventional risk stratification tools, new markers for plaque vulnerability, enhanced thrombogenesis, specific genetic alterations of the autonomic nervous system, cardiac sarcolemmal and contractile proteins, and familial clustering may better segregate patients with atherosclerotic coronary artery disease who are at high risk for SCD from those who may suffer from nonfatal ischemic events. Better understanding of pathophysiological processes, such as postmyocardial infarction remodeling, the transition from compensated hypertrophy to heart failure, and the increased cardiovascular risk of coronary artery disease in the presence of diabetes or even a prediabetic state will help to improve both risk stratification and management. The rapidly developing fields of microchips technology and proteomics may allow rapid and cost-effective mass screening of multiple risk factors for SCD. The ultimate goal is to identify novel methods for risk stratification, risk modification, and prevention of SCD that could be applied to the general public at large.

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Background: Extensive encircling pulmonary vein isolation (EEPVI) is effective for atrial fibrillation (AF). However, the definition of success following ablation is commonly based on the lack of symptoms. The purpose of this study was to determine the incidence of recurrences of AF by daily transtelephonic electrocardiogram (T-ECG), as compared with Holter ECG, after ablation of AF.
Methods: Twenty-two patients with AF underwent EEPVI. Holter ECG tests were performed at one, three, and six months, in addition to a daily T-ECG for the first 180 days after ablation.
Results: A total of 6012 T-ECGs were obtained. Of these, 18.9% (1136) showed AF. Patients with AF were asymptomatic for 41.4% (470) of the episodes. Additionally, in 64% (14 of 22) of the patients, AF recurrences were recorded by T-ECG, whereas Holter ECG tests did not detect AF recurrences in 50% of the patients (7 of 14).
Conclusions: T-ECG is better than Holter ECG in detecting AF relapses. The absence of symptoms should not be interpreted as absence of AF.

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Background: Antiarrhythmic agents may affect electrical remodeling but little is known regarding clinical cases. We evaluated fibrillation cycle length (FCL) of atrial fibrillation (AF) by spectral analysis of fibrillation waves (FW) in surface ECG for patients on antiarrhythmic agents.
Methods and Results: 18 patients (14 males; 58±2 year-old) with paroxysmal AF (pAF) lasting over 30 minutes recorded by Holter ECG were enrolled. FW was purified by subtraction of QRS-T, and calculated by fast Fourier transformation analysis. FCL was defined as reciprocal of mean peak frequency. Temporal variability was expressed as FCL coefficient of variation (FCL-CV). FCL and FCL-CV were calculated at 0, 1, 5, 10, and 30 minutes after the onset of AF. We evaluated three groups: control group (6 patients with no medication), class I group (6 patients with pilsicainide or flecainide), and bepridil group (6 patients with bepridil). FCL showed quick-shortening at first minute in control group (p<0.001), and relatively slow-shortening in class I group. In bepridil group, FCL was not significantly shortened within 30 minutes. FCL-CV did not change, but was significantly larger in bepridil group.
Conclusions: FCL of pAF showed significant shortening in control group, but FCL shortening was suppressed and FCL-CV was larger in bepridil group. This result may indicate the specific effect of bepridil for electrical changes in early phase of pAF.

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Introduction: The electromagnetic interference (EMI) of active implantable medical devices (AIMDs) due to 125–135 kHz and HF (13.56 MHz) radio-frequency identification (RFID) reader/writers are discussed based on in vitro experiments. The purpose of this paper is to clarify the detailed EMI occurrence conditions of both implantable cardiac pacemakers and implantable cardioverter defibrillators (ICDs) when used in proximity to commercial low-band RFID reader/writers.
Methods and results: A total of 20 types of pacemakers and 7 types of ICDs from 9 manufacturers are used in the experiments. The tested RFID reader/writers are 4 types of 125–135 kHz antennas and 26 types of HF antennas. The test system is newly constructed based on the one previously proposed for the estimation of EMI due to mobile phones. The measured reactions are missing of pacing pulses and generation of asynchronous pulses for pacemaker functions and inappropriate tachyarrhythmia detection and delivery of therapy for ICDs. In addition, measured EMI characteristics strongly depend on intermittent period of RFID signals. However, all AIMDs tested return to normal operation once removed from RFID exposure.
Conclusion: The detailed EMI characteristics of AIMDs and low-band RFID reader/writers are obtained to prevent adverse interactions.

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Right atrial appendage tachycardia is not common and can be eliminated by catheter ablation with a high success rate and low recurrence rate. However, the structural properties of the atrial appendage, including blind-ended structure, abundant trabeculations, and reduced wall thickness could make the procedure of catheter ablation difficult, especially if the focus is at the tip of atrial appendage. We describe a case of atrial tachycardia originating from the tip of the right atrial appendage that was eliminated by catheter ablation in spite of some difficulties in manipulation of the catheter and achieving adequate radiofrequency power.

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A 72-year-old woman with sick sinus syndrome (SSS), who had frequent paroxysmal atrial fibrillations (PAfs) and normal cardiac function, was admitted to our hospital due to syncope. PAfs frequently occurred during the first week after DDD pacemaker implantation (PMI), with closed loop stimulation (CLS) rate-adaptive mode off, but were completely suppressed during the second week, with CLS on, and had been well-controlled over three years thereafter. However, PAfs occasionally occurred under intense sympathetic activity during 6 months after PMI as well, and were effectively terminated by disopyramide which had anticholinergic effect. Thus, the development and maintenance of PAf were thought to be associated with destabilized cardiac autonomic activities, that is, sympathetic and parasympathetic dominance, respectively. Additionally, heart rate variability analyses after implementation of CLS revealed the restoration of sympathetic and parasympathetic components. Accordingly, CLS mode was considered to play a critical role in preventing PAf by reflecting autonomic activity in heart rhythm in this SSS patient.

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