Tadashi Hoshiyama

Importance of pericardial fat in the formation of complex fractionated atrial electrogram region in atrial fibrillation

BACKGROUND/OBJECTIVES Pericardial fat (PF) and complex fractionated atrial electrogram (CFAE) are both associated with atrial fibrillation (AF). Therefore, we examined the relation between PF and CFAE area in AF. METHODS The study population included 120 control patients without AF and 120 patients with AF (80 paroxysmal AF and 40 persistent AF) who underwent catheter ablation. Total cardiac PF volume, representing all adipose tissue within the pericardial sac, was measured by contrast-enhanced computed tomography. The location and distribution of CFAE region were identified by left atrial endocardial mapping using a three-dimensional mapping system. We analyzed the significance of total cardiac PF volume and total area of CFAE region on AF, persistence of AF from paroxysmal to persistent form, and the relation between total cardiac PF volume and total CFAE area. We also evaluated the regional distribution of PF volume and CFAE area in five areas of the left atrium (LA). RESULTS Total cardiac PF volume correlated with AF (odds ratio [OR]: 1.024, p<0.001). Total cardiac PF volume and total CFAE area were both independently associated with persistence of AF (OR: 1.018, p=0.018, OR: 1.144, p=0.002, respectively). Multivariate linear regression analysis identified total cardiac PF volume as a significant and independent determinant of total CFAE area (r=0.488, p<0.001). Furthermore, regional PF volume correlated with local CFAE area in an each LA area. CONCLUSIONS PF volume correlated significantly with CFAE area in patients with AF. This finding suggests that PF is directly related to the progression of CFAE area and promotes the pathogenic process of AF.

Total Thrombus‐Formation Analysis System (T‐TAS) Can Predict Periprocedural Bleeding Events in Patients Undergoing Catheter Ablation for Atrial Fibrillation

Background Non–vitamin K antagonist oral anticoagulants are used to prevent thromboembolism in patients with atrial fibrillation. The T‐TAS “Total Thrombus‐formation Analysis System” (Fujimori Kogyo Co Ltd) was developed for quantitative analysis of thrombus formation using microchips with thrombogenic surfaces (collagen, platelet chip [PL] ; collagen plus tissue factor, atheroma chip [AR]). We evaluated the utility of T‐TAS in predicting periprocedural bleeding in atrial fibrillation patients undergoing catheter ablation (CA). Methods and Results After exclusion of 20 from 148 consecutive patients undergoing CA, the remaining 128 patients were divided into 2 treatment groups: the warfarin group (n=30) and the non–vitamin K antagonist oral anticoagulants group (n=98). Blood samples obtained on the day of CA (anticoagulant‐free point) and at 3 and 30 days after CA were used in T‐TAS to compute the thrombus formation area under the curve (AUC; AUC for the first 10 minutes for PL tested at flow rate of 24 μL/min [PL 24‐AUC 10]; AUC for the first 30 minutes for AR tested at flow rate of 10 μL/min [AR 10‐AUC 30]). AR 10‐AUC 30 and PL 24‐AUC 10 levels were similar in the 2 groups on the day of CA. Levels of AR 10‐AUC 30, but not PL 24‐AUC 10, were significantly lower in the 2 groups at days 3 and 30 after CA. Multiple logistic regression analyses identified the AR 10‐AUC 30 level on the day of CA as a significant predictor of periprocedural bleeding events (odds ratio 5.7; 95% CI 1.54–21.1; P=0.009). Receiver operating characteristic analysis showed that the AR 10‐AUC 30 level on the day of CA significantly predicted periprocedural bleeding events (AUC 0.859, 95% CI 0.766–0.951; P<0.001). The cutoff AR 10‐AUC 30 level was 1648 for identification of periprocedural bleeding events. Conclusions These results suggested that the AR 10‐AUC 30 level determined by T‐TAS is a potentially useful marker for prediction of bleeding events in atrial fibrillation patients undergoing CA.

Demonstration of anatomical reentrant tachycardia circuit in verapamil-sensitive atrial tachycardia originating from the vicinity of the atrioventricular node

BACKGROUND The anatomical location of the reentry circuit in verapamil-sensitive atrial tachycardia originating from the vicinity of atrioventricular node (V-AT) is not well clarified. OBJECTIVE To define the reentry circuit of V-AT. METHODS In 17 patients with V-AT, rapid atrial pacing at a rate 5 beats/min faster than the tachycardia rate was delivered from multiple sites of the right atrium (RA) during tachycardia to define the direction of the proximity of the slow conduction area of the reentry circuit. After identification of manifest entrainment and orthodromic capture of the earliest atrial activation site (EAAS), radiofrequency energy was delivered starting at a site 2 cm away from the EAAS in the direction of the pacing site. Radiofrequency energy application site was then gradually advanced toward EAAS until the termination of tachycardia to define the entrance of the slow conduction area. RESULTS The EAAS was orthodromically captured by pacing delivered from one of the high anterolateral RA (n = 6), high posteroseptal RA (n = 9), and RA appendage (n = 2). Radiofrequency energy delivery to the site, 10.1 ± 2.8 mm away from the EAAS, terminated V-AT immediately after the onset of delivery (2.9 ± 1.0 seconds). The successful ablation site located outside the Kochs triangle, being more distant from the His bundle site than the EAAS (12.4 ± 2.9 vs 6.4 ± 1.9 mm; P <.0001). CONCLUSION The reentry circuit of V-AT located outside the Kochs triangle. V-AT was eliminated by the radiofrequency energy delivered to the entrance of the reentry circuit, which was more distant from the His bundle site than the EAAS, under the navigation of entrainment.

Atrial Flutter Following Ethanol Infusion in the Vein of Marshall

Key Teaching Points • The critical isthmus of atrial flutter, which is formed secondary to the low-voltage area created by ethanol infusion in the vein of Marshall (VOM), is rare. • It should be noted that although ethanol infusion in the VOM is effective for perimitral flutter, it may create another reentrant arrhythmia. • Additional radiofrequency catheter ablation from the endocardial side may prevent proarrhythmic effect.

Colchicine reduced pericardial effusion due to postcardiac injury syndrome following cardiac resynchronization therapy implantation

We present a case of postcardiac injury syndrome with pericardial effusion following cardiac resynchronization therapy implantation which was treated by only colchicine. Although treatment using colchicine is not as common as NSAIDs or steroids, colchicine seems to be an effective and safe treatment option for the syndrome.

Usefulness of non-contact mapping for catheter ablation of ventricular tachycardias originating at the right ventricular outflow tract

Different QRS morphologies are often observed in idiopathic ventricular tachycardias or premature ventricular contractions originating from the right ventricular outflow tract (RVOT). However, the precise mechanism underlying multiple QRS morphologies has not been clarified adequately. The purpose of this study was to examine the mechanism underlying different QRS morphologies in RVOT arrhythmia. We also investigated the usefulness of non‐contact mapping guided radiofrequency catheter ablation for RVOT arrhythmia.

Electrophysiologic mechanism of typical atrial flutter termination by nifekalant: effect of a pure IKr -selective blocking agent.

Little is known about the effect of nifekalant, a pure IKr‐selective blocker, on typical atrial flutter (AFL) and its termination mechanism.