Conventional heart rate variability (HRV) indices comprise time domain and frequency domain HRV indices that not only reflect the autonomic control of the heart but also serve as prognostic markers of various cardiovascular disorders. These indices have been extensively investigated as prognostic factors for patients who develop coronary artery diseases including myocardial infarction (MI). Non-linear indices of HRV such as the long (β)- and short (αl, and α2)-term fractal component indices and approximate entropy analysis have been clinically applied. In addition, heart rate turbulence (HRT) and the deceleration capacity (DC) of heart rate have been studied as potential HRV indices for predicting untoward outcomes of cardiovascular diseases. This overview examines HRV indices and their roles in the setting of cardiovascular disorders including sudden cardiac death. We describe changes in HRV indices and clarify the relationship between prognosis and the indices in critically ill patients admitted to intensive care units.

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Back ground: Three-dimensional mapping systems such as the non-contact mapping system (EnSite) have been utilized for radiofrequency catheter ablation (RFCA) in cases with various kinds of arrhythmias.
Methods: An EnSite system was utilized for RFCA in 12 patients with right-sided atrial tachycardia (AT). The patients were classified into two groups according to the focus of the AT in the right atrium (RA). The patients in whom the EnSite array was positioned near the focus of the AT were defined as group A, whereas those patients in whom the EnSite array was located less near the focus were defined as group B. RF energy was applied under the guidance of the mapping with the EnSite array. We investigated the relationship between the position of the EnSite array and the focus of the AT in terms of the mapping accuracy in both groups.
Results: Even though the accuracy of the mapping of the breakout site and arrhythmia origin was comparable between groups A and B, the distance between the successful CA sites and the presumed AT focus according to the EnSite mapping was significantly shorter in group A than group B.
Conclusions: As the location of the focus of the AT becomes closer to the proximal and distal ends of the ESB, the mapping accuracy deteriorates.

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Background: Active-fixation screw-in leads are associated with initially high thresholds. However, pacing thresholds have been shown to improve within several minutes after screw-in. The aim of this study is to investigate the long-term stability of rapidly improved pacing thresholds following the implantation of active-fixation screw-in leads.
Methods: We performed a prospective observational study on 68 consecutive patients, who were referred for an initial pacemaker or implantable cardioverter defibrillator implantation. Pacing thresholds, sensing amplitudes, and lead impedances were measured immediately after screw-in. If the initial pacing threshold was higher than 2.0 volts, lead reposition was performed. If the initial pacing threshold was lower than 1.0 volts, the lead position was considered adequate. If the initial pacing threshold was slightly high, i.e., between 1.0 and 2.0 volts, all parameters were measured again 5 minutes after screw-in without lead repositioning, and 1 week, 1 month, 6 months, and 1 year after the procedure.
Results: Fifty-three atrial leads and 59 ventricular leads were implanted using active-fixation screw-in leads. The initial pacing threshold was slightly high, i.e., between 1.0 and 2.0 volts in 16 (30%) atrial leads and 28 (47%) ventricular leads. Pacing thresholds significantly improved after 5 minutes in both atrial and ventricular leads as follows: 1.5±0.2 to 0.9±0.3 volts (p<0.05) in atrial leads and 1.5±0.3 to 0.9±0.3 volts (p<0.05) in ventricular leads. These improved pacing thresholds remained stable during the first year and were 0.8±0.3 volts in atrial leads and 0.8±0.2 volts in ventricular leads after the initial year. P- and R-wave amplitudes did not change significantly during the follow-up. Lead impedances decreased 1 week after the procedure and remained stable in both atrial and ventricular leads.
Conclusions: Slightly high pacing thresholds using active-fixation screw-in leads improved rapidly and remained stable in the long term. An acute pacing threshold of <2.0 volts immediately after screw-in may change to an acceptable value without lead repositioning.

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Background: Although amiodarone (AMD) is applied for implantable cardioverter-defibrillator (ICD) patients to reduce VT/VF events, its actual benefit and long-term efficacy are unclear. In the present study, we retrospectively evaluated the incidence of VT/VF events in ICD patients with and without AMD.
Methods and results: The study population consisted of 77 consecutive patients with ICD therapy and structural heart diseases. They were followed up for 24±3 months, and the incidences of VT/VF events or hospitalization were evaluated. When they were divided into two groups with and without VT/VF events (42:35), univariate analysis indicated a higher incidence of cardiomyopathy as the basic disease, VT as the initial arrhythmic diagnosis, higher levels of total bilirubin, and a lower incidence of AMD use in patients with VT/VF events. When they were divided by AMD use (24/53), VT/VF events were observed in 8/24 in patients with AMD (33.3%) and 34/53 without AMD (64.2%, p=0.012). In sub-group analysis based on left ventricular ejection function (LVEF), the VT/VF event rate was lower in the AMD group in patients with LVEF<40% (p=0.007).
Conclusions: AMD was considered to reduce VT/VF events in ICD patients, especially in the population with structural heart disease and lower LVEF.

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Introduction: We assessed the effects of pilsicainide, a pure Na⁺ channel blocker, and nifekalant, a pure rapid delayed rectifier potassium current (IKr) blocker, on the electrophysiological characteristics within the pulmonary vein (PV) and at the PV-left atrial (LA) junction.
Methods and Results: We used a basket catheter for PV mapping in 38 patients with paroxysmal atrial fibrillation (AF). Programmed stimulation was performed in the distal PV and PV-LA junction before and after the infusion of pilsicainide (1 mg/kg; n=24) or nifekalant (0.3 mg/kg; n=14). Both drugs significantly prolonged the effective refractory period (ERP) of the distal PV and PV-LA junction. Pilsicainide significantly decreased the ERP heterogeneity of the PV and PV-LA junction (36±43 vs. 9±60 ms, P<0.05). In contrast, nifekalant significantly increased the ERP heterogeneity of the PV and PV-LA junction (from 38±34 to 60±46 ms, P<0.01). Pilsicainide significantly prolonged the conduction time (S1-A1) from the distal PV to the PV-LA junction (from 42±12 to 63±26 ms, P<0.001), whereas this did not change with nifekalant.
Conclusions: In AF patients, pilsicainide has antiarrhythmic effects mainly on the distal PV by modifying the ERP and conduction properties. In contrast, nifekalant has antiarrhythmic effects mainly on the PV-LA junction by modifying the ERP.

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A 32-year-old man developed systemic right ventricular (RV) heart failure after ventricular septal defect (VSD) closure and tricuspid valve replacement for corrected transposition of the great arteries with VSD and Ebstein anomaly. He subsequently experienced RV failure with wide QRS and atrial fibrillation (AF). Because corrective surgery for this condition seemed over risky, we decided to perform cardiac resynchronization therapy with implantation of an implantable cardioverter defibrillator (CRT-D). After CRT-D device implantation, the patient showed improved performance status in terms of New York Heart Association functional class, B-type brain natriuretic peptide levels, RV ejection fraction and cardiac electrical rhythm. CRT-D implantation is a useful approach for systemic RV failure with wide QRS duration showing right bundle branch block and AF.

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We report on a 77-year-old man who had been diagnosed with diabetes and hypertension. He had also been diagnosed with cardiomyopathy, although details were unclear. He was referred from local clinics after becoming aware of shortness of breath on exertion. Electrocardiogram showed a 2:1 atrioventriculer block with a wide QRS beat. Echocardiography and cardiac MRI showed very poor left ventricular contraction with chamber dilatation. Echocardiography showed left bundle branch block with dyssynchrony. On the electrophysiological testing, ventricular tachycardia and ventricular fibrillation were not induced, and no significant findings on coronary angiography had revealed at that time. He had shortness of breath on exertion with bradycardia-tachycardia syndrome and low cardiac function, and his electrophysiological examination was negative. Therefore we decided to implamt cardiac resynchronization therapy pacemaker (CRT-P). During a guide-wire insertion for placement of the left ventricular lead into the coronary venous branch, the tip of the guide-wire suddenly broke off. We attempted to recover the fragment using a snare catheter, but were unsuccessful. Since then the patient has been under observation, with no clinical manifestations seen.

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Cardiostim is a congress dedicated to devices, interventional electrophysiology and non-invasive electrophysiology. It was born in 1978, and imagined by Dr Jacques Mugica for educational purposes, and is held traditionally in Nice, French Riviera, on even years. This 2010 edition had 5700 participants coming from 92 countries. A large Japanese attendance was present and two joint sessions were organized with the Japanese Heart Rhythm Society.
The program was divided into three sections: updates, education, and presentations based on selected submitted abstracts.
Following is a summary of these selected abstracts, which does reflect the trends of our specialty, and of technological advances. For devices, telemedicine, MRI compatibility, full automaticity were the main topics. In cardiac pacing, respect of spontaneous AV conduction is confirmed as being essential, and positioning of the right ventricular lead remains an issue. For ICDs, better definition of candidates, utility of DFT testing, and reduction in inappropriate shocks are the main concerns. In CRT, extension of indications toward earlier stages of HF, implementation of hemodynamic sensors, and new approaches to the left ventricle are at the first row.
Ablation techniques benefit from new technologies: interest and limits of cryo-ablation, new radio-frequency catheters, visualization of ablative lesions, contact control, and use of imaging techniques. The goals are: to speed up procedures, make them safer, and more efficient.

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