Prolonged Inflation Technique Using a Scoring Balloon for Severe Calcified Lesion.

Percutaneous coronary intervention for the treatment of a severe calcified lesion is still one of the most technically challenging areas of interventional cardiology. Calcified lesions are a cause of stent underexpansion, which significantly increases the subsequent risks of in-stent restenosis and thrombosis, even when drug-eluting stents are used. In this report, we describe the usefulness of prolonged inflations using a scoring balloon catheter (Scoreflex) for severe calcified lesions. Prolonged inflation using a scoring balloon enables an adequate dilation for treatment of a severe calcified plaque that was unresponsive to conventional technique with or without rotational atherectomy.

Black hole restenosis after drug-eluting stent implantation for in-stent restenosis: potential mechanism and optimal strategy.

In-stent restenosis (ISR) has long remained as the major limitation of coronary stenting. The use of drug-eluting stent (DES) reduces the risk of repeat revascularization without an increase of death and myocardial infarction, compared to the standard bare metal stents. DES has also demonstrated markedly to reduce ISR for complex lesions. However, ISR after DES implantation still occurs and optimal treatment for ISR after DES has not been established. Herein, we report 3 cases with black hole restenosis confirmed by intravascular ultrasound at the site of overlapped DES and discuss potential mechanism and optimal strategy for this phenomenon.

A left atrial appendage thrombus that developed during prophylactic low-dose dabigatran treatment resolved after switching to apixaban.

We describe a case of atrial fibrillation in which an intracardiac thrombus that could not be prevented with "low-dose" dabigatran treatment was resolved by switching to apixaban treatment. Thrombolysis using direct oral anticoagulants (DOACs) could be a therapeutic option for patients with intracardiac thrombi, although the efficacies of different DOACs seem to differ and need further examination.

Pilsicainide for atrial fibrillation.

Pilsicainide is a class IC antiarrhythmic drug, which has a pure sodium channel blocking action with slow recovery pharmacokinetics. In experimental studies, pilsicainide has a depressant effect on intra-atrial conduction and a prolonging effect on the atrial effective refractory period (ERP). In patients with paroxysmal atrial fibrillation (AF), pilsicainide significantly prolonged the ERP of the distal pulmonary vein (PV), PV-left atrium (LA) junction and LA, and the conduction time from the distal PV to the PV-LA junction. In some patients, PV-LA conduction block has been observed just before pilsicainide-induced termination of AF; this isolation of the PV may provide a new insight into the mechanism of pharmacological conversion of AF. Hybrid therapy with pilsicainide and PV isolation (by radiofrequency catheter ablation) appears to be an effective therapeutic approach for AF. The pharmacological PV isolation by pilsicainide and its suppression of focal discharges from atrial tissue may prevent the development of AF after unsuccessful ablation.

Electrophysiologic properties of pulmonary veins assessed using a multielectrode basket catheter.

OBJECTIVES: The purpose of the present study was to evaluate the electrophysiologic properties within the pulmonary vein (PV) and at the PV-left atrial (LA) junction. BACKGROUND: It has been recognized that atrial fibrillation (AF) can originate from PVs. However, the electrophysiologic properties of the PV have not been well characterized. METHODS: Thirty-two bipolar electrograms were recorded simultaneously from a basket catheter placed in 81 PVs of 48 patients with paroxysmal AF. The programmed stimulation was performed in the distal PV and PV-LA junction. Activation maps of PVs were analyzed from episodes of spontaneous onset of AF and initiation of induced AF by a single extrastimulus. RESULTS: The effective refractory period (ERP) of the distal PV was significantly shorter than that of the PV-LA junction (177 +/- 43 vs. 222 +/- 30 ms, p < 0.0001). The conduction delay from the distal PV to the PV-LA junction was significantly longer than that from the PV-LA junction to distal PV (73 +/- 40 vs. 32 +/- 17 ms, p < 0.0001). During initiation of AF, a short coupled extrastimulus or rapid, repetitive focal activities originating from the PV formed a PV-LA reciprocating re-entrant circuit involving exit and entrance breakthrough points at the PV-LA junction. Also, an unstable re-entrant circuit within the PV was observed. CONCLUSIONS: The presence of ERP heterogeneity and anisotropic conduction properties within the PV and at the PV-LA junction may be crucial to promote re-entry formation and thus might play an important role as a substrate for the maintenance of AF.

Effect of Bachmann's bundle pacing on atrial fibrillation: electrophysiologic assessment.

BACKGROUND: It has recently been reported that simultaneous multisite atrial pacing, Bachmann's bundle (BB) pacing, and coronary sinus (CS) pacing are useful for preventing the induction of atrial fibrillation (AF). HYPOTHESIS: We investigated whether a simple pacing approach via BB could reduce the induction of AF by extrastimuli (S2) from the right atrial appendage (RAA). METHODS: Programmed electrical stimulation was performed from the RAA and the area of BB at the superior aspect of the atrial septum, and bipolar recordings were obtained from the RAA, BB, and CS in 14 patients. RESULTS: In five patients, AF was induced with critically timed RAA-S2 delivered during RAA pacing. However, AF was not induced in any patient when RAA-S2 was delivered during BB pacing. The duration of the P wave during BB pacing was significantly shorter than that during RAA pacing and sinus rhythm (BB 80 +/- 16 ms vs. RAA 106 +/- 36 ms vs. sinus rhythm 100 +/- 24 ms, p < 0.05). The intra-atrial conduction time to the distal coronary sinus (CSd) caused by early S2 at the RAA was significantly reduced by BB pacing (BB 114 +/- 22 ms vs. RAA 157 +/- 35 ms, p < 0.001). CONCLUSION: Bachmann's bundle pacing reduces atrial conduction time caused by RAA-S2 and may be useful for preventing the induction of AF.

Incidence of intussusception as studied from a hospital-based retrospective survey over a 10-year period (2001-2010) in Akita Prefecture, Japan.

One concern about rotavirus vaccines is its possible association with intussusception. Thus, it is necessary to determine the baseline incidence for intussusception in the first year of life in places where rotavirus vaccines are introduced. However, few safety data exist for the period at which the first dose of Rotarix and RotaTeq are allowed to administer in Japan. The first dose of Rotarix is scheduled to administer at 6-20 weeks of age and that of RotaTeq is scheduled to administer at 6-24 weeks of age; the upper limits for these vaccines is later than the upper limit recommended by the World Health Organization by 5 and 9 weeks, respectively. We performed a retrospective cross-sectional study by reviewing medical charts of all hospitals that provided pediatric beds in Akita Prefecture, Japan, and identifying the cases of intussusception that met the Brighton criteria level 1 in these hospitals between January 2001 and December 2010. During this 10-year period, 122 children younger than 1 year of age were diagnosed with intussusception. The incidence of intussusception was estimated at 158 per 100,000 person-years among children younger than 1 year (95% confidence interval, 131-188), 10 per 100,000 person-years for children aged 0-2 months, 165 for children aged 3-5 months, and 300 for children aged 6-8 months. This rapid and substantial increase in the incidence of intussusception during the first year of life should be considered when formulating the immunization schedule for administering rotavirus vaccines in Japan.

New approach to pulmonary vein isolation for atrial fibrillation using a multielectrode basket catheter.

BACKGROUND: Pulmonary vein (PV) isolation using a circular catheter creates an entrance block from the left atrium (LA) to the PV, which eliminates paroxysmal atrial fibrillation (PAF). A new approach to PV isolation during distal PV pacing is to use a basket catheter. METHODS AND RESULTS: Fifty consecutive patients with PAF underwent basket-catheter-guided PV isolation. PV pacing was performed from the distal electrode pair of the basket catheter. The exit breakthrough point was targeted for segmental PV isolation. The endpoint was the elimination of bidirectional PV - LA conduction. A repeat ablation procedure was performed in 12 of 14 patients who had recurrence of AF. The recovery of PV -LA conduction was noted in 24 of the 48 PVs, and 5 PVs (21%) had unidirectional block. At 12 months, 80% of patients were free of AF without antiarrhythmic drugs. No PV stenosis >50% was detected at 12 months after the procedure. CONCLUSIONS: This new approach for PV isolation during distal PV pacing using a basket catheter is useful for confirming bidirectional PV - LA conduction block. PV isolation that creates not only an entrance block but also an exit block at the PV - LA junction may be required to cure paroxysmal AF.

Comparison of 2 mapping strategies for pulmonary vein isolation.

BACKGROUND: Pulmonary vein (PV) isolation using a circular catheter (CC) creates an entrance block from the left atrium (LA) to PV to eliminate paroxysmal atrial fibrillation (PAF). We describe a new approach for PV isolation during distal PV pacing using a basket catheter (BC). The purpose of the present study was to compare 2 mapping strategies for PV isolation. METHODS AND RESULTS: Of 100 consecutive patients with PAF, 50 underwent CC-guided PV isolation and 50 underwent BC-guided PV isolation. During CC-guided ablation, the endpoint was the elimination of PV potentials based on the entrance block from the LA to PV. During BC-guided ablation during distal PV pacing, the endpoint was the elimination of bidirectional PV-LA conduction. At 12 months, 62% of patients who underwent CC ablation and 80% of patients who underwent BC ablation were free of symptomatic PAF without the use of antiarrhythmic drugs (p<0.05). The incidence of mild (<50%) PV stenosis in BC ablation was significantly lower than that in CC ablation (12 vs 24%, p<0.01). CONCLUSIONS: This new approach for PV isolation during distal PV pacing using BC is useful for confirming a bidirectional PV-LA conduction block and is more effective than CC ablation.

Conduction recovery after pulmonary vein isolation for atrial fibrillation.

BACKGROUND: Although pulmonary vein (PV) isolation is useful for curing atrial fibrillation (AF), its recurrence rate is still high, so the aim of the present study was to investigate the cause of recurrence after PV isolation. METHODS AND RESULTS: Eighty-five patients with paroxysmal AF underwent PV isolation and AF recurred in 48 patients after the first session. Thirty of these 48 patients who underwent a second session were evaluated. In 49 (71%) of 69 PVs ablated in 25 patients (83%), recovery of conduction was observed between the left atrium and PV. In 45 (92%) of 49 PVs, conduction recurrences were seen from the same segment or part of a segment that was ablated in the first session. However, in the other 4 PVs (8%), conduction recurrences occurred in a different segment that had not been ablated before. In the second session, the mean number of segments ablated in the PV ostium was significantly less than in the first session (2.3+/-5.0 vs 1.4+/-6.0, p<0.01). After the second session, 16 patients (53%) did not show recurrence of AF. CONCLUSION: The major cause of recurrence of PV isolation was recovery of PV conduction from the same segment that had been ablated in the PV ostium. Therefore, an additional session may be necessary to increase the success rate.

Hybrid therapy with pilsicainide and pulmonary vein isolation for atrial fibrillation.

BACKGROUND: Pulmonary vein (PV) isolation is commonly performed in patients with drug-refractory atrial fibrillation (AF) and in cases of unsuccessful ablation, antiarrhythmic agents that were ineffective before the ablation sometimes become effective afterward. Therefore, the effects and mechanisms of hybrid therapy with pilsicainide and PV isolation for AF were assessed in the present study. METHODS AND RESULTS: Seventy-four patients with paroxysmal AF in whom pilsicainide was ineffective underwent PV isolation. If AF recurred, a second procedure was performed and if AF recurred again, pilsicainide was re-administered. After the first procedure, AF recurred in 42 patients, and a second procedure was performed in 31 patients, of whom 28 had recovery of left atrial (LA)-PV conduction and non-PV foci were identified in 3. After the second session, ablation eliminated AF without drugs in 53 (72%) patients. Pilsicainide suppressed the conduction properties at the LA-PV junction. In 21 patients with recurrence of AF, pilsicainide was re-administered and eliminated AF in 11 patients (success with pilsicainide: 86%). CONCLUSIONS: In cases of unsuccessful PV isolation, pilsicainide may prevent AF by modifying the LA-PV conduction properties. Hybrid therapy with pilsicainide and PV isolation may be an effective therapeutic approach for AF.

Predictors of successful catheter ablation for atrial fibrillation using the pulmonary vein isolation technique.

OBJECTIVES: Pulmonary vein isolation has been performed to cure atrial fibrillation (Af). However, the recurrence rate of Af is relatively high, and additional sessions are sometimes required. The predictors of successful pulmonary vein isolation were evaluated. METHODS: The study population consisted of 52 patients (41 men, mean age 55 +/- 9 years) with Af who underwent pulmonary vein isolation. A second session was required in 22 patients with recurrence of Af after the first session. Pulmonary vein isolation eliminated Af in 38 patients after 1 or 2 sessions. Patients with successful pulmonary vein isolation (n = 39) were compared with those with unsuccessful pulmonary vein isolation despite 2 sessions (n = 13). RESULTS: The patients in the successful group had significantly higher incidence of paroxysmal Af (92% vs 46%, p < 0.001) and lower incidence of mitral regurgitation (10% vs 46%, p < 0.01) than those in the unsuccessful group. However, there was no significant difference between the two groups with regard to age, history of Af, cardiopulmonary ratio, dimension of left atrium, ejection fraction, pulmonary vein diameter, and pulmonary vein number. CONCLUSIONS: Type of Af and presence of mitral regurgitation are significant predictors of successful pulmonary vein isolation.

Simultaneous catheter mapping of the pulmonary veins in focal atrial fibrillation: significance of rapid focal activation, effectiveness for catheter ablation.

Most focal atrial fibrillation (AF) is initiated by premature beats from the pulmonary veins (PV), and ablation of these foci can effectively cure AF. We investigated the efficacy of focal ablation and the role of rapid focal activation (RFA) in the maintenance of AF using simultaneous multisite catheter mapping in four PVs. Forty-two patients with frequent attacks of paroxysmal AF were included in the study population. Bipolar electrograms were simultaneously recorded from all four PVs. RFA was determined at AF onset, during sustained AF, or just before the spontaneous termination of AF. RFA was continuously observed not only at a triggered PV, but also at all sites including an opposite non-triggered PV, coronary sinus and high right atrium in sustained AF (>10 minutes), whereas RFA was observed only in the triggered PV and not at the other sites in nonsustained AF. Once RFA ceased, AF terminated immediately. After a mean follow-up of 21 months, focal ablation had eliminated AF without drugs in 24 patients (57%). The technique of simultaneous mapping of the PV using microcatheters is a feasible and effective method for mapping and ablation of focal AF originating from the PV. RFA arising from PVs is important not only as a trigger of onset, but also in the maintenance of AF.

Evaluation of the recurrence of atrial fibrillation after pulmonary venous ablation.

OBJECTIVES: The mechanism of the recurrence of atrial fibrillation after pulmonary vein ablation was evaluated. METHODS: Eighty patients with atrial fibrillation underwent pulmonary vein ablation. If extrasystoles or atrial fibrillation initiations were frequent, focal ablation was performed at the site of the earliest activation. If the patient had little or no ectopy, all pulmonary veins with distinct and late pulmonary vein potentials were targeted for pulmonary vein isolation, which was achieved by minimal segmental ablation limited to the ostial site with the earliest pulmonary vein potentials. RESULTS: Focal ablation or pulmonary vein isolation was performed in 42 and 38 patients, respectively. After focal ablation, atrial fibrillation recurred in 23 patients and re-ablation was performed in 10:7 at sites near the previous source, 2 at a different part of the same pulmonary vein, and 1 at a different pulmonary vein. After pulmonary vein isolation, atrial fibrillation recurred in 19 patients and re-ablation was performed in 14:8 due to recovery of atrio-pulmonary vein conduction, 3 at non-pulmonary vein foci, 2 at pulmonary vein ostia proximal to the previous pulmonary vein isolation, and 1 at a different pulmonary vein. CONCLUSIONS: After focal ablation, atrial fibrillation recurred from other foci in the same pulmonary vein or other pulmonary veins. Therefore, three or four pulmonary veins should be isolated. However, atrial fibrillation recurred after pulmonary vein isolation due to the recovery of atrio-pulmonary vein conduction or non-pulmonary vein foci. Further development of new mapping and ablation systems to detect the foci and create a complete lesion at the pulmonary vein ostium may be necessary.

Effects of the NA+ channel blocker pilsicainide on the electrophysiologic properties of pulmonary veins in patients with atrial fibrillation.

INTRODUCTION: Na+ channel blockers are used to treat atrial fibrillation (AF). However, the effects of Na+ channel blockers on the electrophysiologic properties of pulmonary veins (PVs) are not well characterized. The aim of the present study was to evaluate the effect of the pure Na+ channel blocker pilsicainide on the PVs. METHODS AND RESULTS: PV mapping using a basket catheter was performed in 28 patients with paroxysmal AF. Twenty-eight PVs, including 20 left superior and 8 right superior PVs, were studied. Programmed stimulation was performed in the distal PV and PV-left atrial (LA) junction before and after infusion of pilsicainide (1 mg/kg). Pilsicainide significantly prolonged the effective refractory period (ERP) of the distal PV from 163 +/- 44 msec to 192 +/- 53 msec (P < 0.001), PV-LA junction from 227 +/- 48 msec to 235 +/- 52 msec (P < 0.05), and LA appendage from 225 +/- 55 msec to 245 +/- 48 msec (P < 0.05). Pilsicainide significantly prolonged the conduction time from the distal PV to PV-LA junction from 45 +/- 14 msec to 70 +/- 26 msec (P < 0.0001). In 3 of 5 patients who experienced AF termination with pilsicainide, PV-LA conduction block was observed just before AF termination. CONCLUSIONS: Pilsicainide can modify ERP heterogeneity and conduction properties in the PV and at the PV-LA junction. Because the PV and PV-LA junction have important roles as substrates for AF maintenance, pilsicainide may terminate AF by pharmacologic PV isolation.

Genetic analysis of Brugada syndrome in Western Japan: two novel mutations.

BACKGROUND: Brugada syndrome is a form of idiopathic ventricular fibrillation characterized by right bundle-branch block pattern and ST elevation in the right precordial leads of the ECG. The SCN5A gene encodes the alpha-subunit of the human heart sodium channel, which plays a critical role in cardiac excitability, and mutations of SCN5A could underlie Brugada syndrome. METHODS AND RESULTS: To detect mutations of SCN5A, DNA samples from 12 Japanese patients with Brugada syndrome were analyzed using direct sequencing. Two patients had novel mutations, G292S and S835L, but no other mutations of SCN5A were detected in the remaining patients. The first mutation, G292S, was identified adjacent to the pore-lining region between the DIS5 and DIS6 transmembrane segments of SCN5A, and the second mutation, S835L, was in the intracellular loop connecting the DIIS4 to DIIS5. Both mutations were not detected in 100 unrelated control subjects. CONCLUSION: Two novel SCN5A mutations have been found in Japanese patients with Brugada syndrome.