Zero-fluoroscopy ablation for cardiac arrhythmias: A single-center experience in Japan.

BACKGROUND: Exposure to radiation during catheter ablation procedures poses a risk to the heath of both the patient and electrophysiology laboratory staff. Recently, the feasibility and effectiveness of zero-fluoroscopy ablation have been reported. However, studies on the outcomes of zero-fluoroscopy ablation in Japan remain limited. This study investigated the outcomes of zero-fluoroscopy ablation for cardiac arrhythmias at a Japanese institute. METHODS AND RESULTS: We present a retrospective analysis of the safety, efficacy, and feasibility data from 221 consecutive patients who underwent zero-fluoroscopy ablation. Of these patients, 181 had atrial fibrillation, 17 had paroxysmal supraventricular tachycardia, 13 had atrial tachycardia, 6 had ventricular tachycardia, and 4 had ventricular premature contractions. We performed zero-fluoroscopy ablation using three-dimensional electro-anatomical mapping systems and intracardiac echocardiography imaging. Ultrasound-guided sheath insertion was performed on all cases. Our experience includes exclusively endocardial cardiac ablations. The mean follow-up was 24 months. The recurrence rates were 25.4% for atrial fibrillation, 5.9% for paroxysmal supraventricular tachycardia, 15.4% for atrial tachycardia, 33.3% for ventricular tachycardia, and 25% for ventricular premature contraction. Complications occurred in two patients (0.9%), and there was no occurrence of death. A fluoroscopic guide was used in three cases for the confirmation of vascular access (one case) and for complications (two cases). CONCLUSIONS: Zero-fluoroscopy ablation was routinely performed without compromising on safety and efficacy. This approach may eliminate the exposure to radiation for all individuals involved in this procedure.

360-degree screen-free floating 3D image in a crystal ball using a spatially imaged iris and rotational multiview DFD technologies.

A rotational multiview depth-fused 3D (DFD) display and 360-deg displaying optics using a spatially imaged iris method are proposed to realize a 360-deg 3D image. This method enables displaying clear floating images in a crystal ball. Its symmetric optics provide clear and natural 360-deg images with smooth motion parallax in horizontal and vertical directions using the directional selectivity of a spatially imaged iris method and natural 3D images of a rotational multiview DFD display.

The role of soluble fibrin during anticoagulant therapy: a case report.

Warfarin, dabigatran, and apixaban are used for preventing ischemic stroke due to non-valvular atrial fibrillation (NVAF). However, it is often challenging to select the appropriate anticoagulant. We present the case of a 70-year-old male patient with persistent NVAF who developed pulmonary thromboembolism (PTE), deep vein thrombosis (DVT), and left atrial thrombus during anticoagulant therapy with warfarin. Intravenous recombinant tissue plasminogen activator was administered during his acute PTE. Heparin and apixaban were administered over 28 days; heparin was discontinued after the DVT resolved, while apixaban was administered to prevent ischemic stroke. Two days after heparin was discontinued, the patient experienced an ischemic stroke. Dabigatran was administered for secondary ischemic stroke prevention. Soluble fibrin (SF) levels remained elevated during treatment with heparin and apixaban and returned to normal after apixaban was replaced with dabigatran. Monitoring of SF may be useful as an index for selection of anticoagulants.

Usefulness and safety of intracoronary administration of nicorandil for evaluating fractional flow reserve in Japanese patients.

BACKGROUND: Fractional flow reserve (FFR) is useful for determining the functional significance of epicardial coronary stenosis and may facilitate clinical decision making in patients with an equivocal coronary stenosis for coronary revascularization. Therefore, determining an efficient and safe method to achieve hyperemia is important for evaluating FFR. We investigated the usefulness and safety of intracoronary bolus administration of nicorandil compared with intravenous administration of adenosine triphosphate (ATP) for evaluating FFR in Japanese patients with suspected angina pectoris. METHODS: First, we evaluated the most appropriate hyperemic dose of nicorandil in the first 11 consecutive patients out of 101 Japanese patients. Next, we compared the FFR induced by ATP and by 2 mg of nicorandil in 130 vessels of the 101 patients. RESULTS: FFR was measured according to nicorandil dose in 14 vessels among 11 of the 101 patients; 92.9% of the patients achieved hyperemia with 2 mg of nicorandil. The FFR values obtained with ATP were significantly correlated with those obtained with 2 mg of nicorandil (regression coefficient = 0.974, R(2) = 0.933, P < 0.001). There were no hypotension cases needing a vasopressor after ATP or nicorandil administration, and there was 1 case of transient second-degree atrioventricular block after ATP administration. The time taken to achieve hyperemia after nicorandil administration (18.9 ± 9.6 seconds) was significantly shorter than that after ATP administration (197.9 ± 23.8 seconds) (P < 0.001). CONCLUSIONS: Intracoronary nicorandil administration is more useful than and as safe as intravenous administration of ATP for evaluating FFR in Japanese patients.

The relationship between paroxysmal atrial fibrillation and coronary artery spasm.

BACKGROUND: Coronary artery spasm has recently been reported as a complication of the ablation of atrial fibrillation (AF). It may be induced by cardiac autonomic nervous dysfunction during radiofrequency catheter ablation of AF. However, the underlying mechanism is not clear. We hypothesized that patients with paroxysmal AF coincidentally exhibit coronary artery spasm. METHODS: A total of 51 patients were enrolled in a case control study to clarify the relationship between paroxysmal AF and coronary artery spasm. We evaluated 17 patients with paroxysmal AF (AF group) and 34 patients without paroxysmal AF (control group). Drug-induced coronary artery spasm provocation tests were performed by intracoronary administration of acetylcholine or ergonovine. RESULTS: The AF group consisted of nine males and eight females, mean age 67 ± 10 years. The control group consisted of 16 males and 18 females, mean age 60 ± 14 years. In the AF group, coronary artery spasm was induced in 13 patients (76.5%) before AF ablation. In the control group, coronary artery spasm was induced in three patients (8.8%). Coronary artery spasm was more frequently induced in patients with AF (76.5% vs 8.8%; odds ratio, 33.583; 95% confidence interval, 6.5732-171.58; P < 0.0001). In the AF group, ventricular fibrillation and AF were recorded immediately after right coronary artery spasm induction in one patient. CONCLUSIONS: Paroxysmal AF patients have high positive rates of drug-provoked coronary artery spasm. Patients with paroxysmal AF may coincidentally exhibit coronary artery spasm.

Resolution of left atrial appendage thrombus with apixaban.

Left atrial appendage (LAA) thrombosis is an important cause of cardiogenic cerebral thromboembolism. Apixaban is a member of the class of novel oral anticoagulants (NOAC) and is superior to warfarin in preventing stroke or systemic embolism, causes less bleeding, and results in lower mortality in patients with atrial fibrillation. There are few reports of resolution of LAA thrombus with other NOAC. We present a 72-year-old male patient with persistent atrial fibrillation associated with left atrial thrombus. Sixteen days of apixaban treatment showed complete thrombus resolution. In this study, soluble fibrin and D-dimer levels decreased without prolongation of international normalized ratio (INR) and activated partial thromboplastin time (APTT).

The relationship between right ventricular lead position and paced QRS duration.

BACKGROUND: The relationship between the anatomical location of right ventricular pacing site and paced QRS duration is unclear. In this study, we aimed to investigate the relationship between right ventricular pacing site and paced QRS duration using cardiac angiography. METHODS: Fifty patients were implanted with pacemakers. The right ventricular lead position was determined from the findings of cardiac angiography and the paced QRS duration was measured. Cardiac angiography was used to display the right ventriculogram (RVG) and the left ventriculogram (LVG). The RVG view was divided into three areas and the LVG view was divided into four areas. RESULTS: The paced QRS duration value was significantly longer in the right ventricular apex area compared with the outflow and inflow areas (160 ± 15 ms vs 140 ± 15 ms, P = 0.02, and vs 133 ± 17 ms, P < 0.001, respectively), but those values were not statistically significantly different between the right ventricular outflow and the right ventricular inflow areas (140 ± 15 ms vs 133 ± 17 ms, P = 0.187). When assessed with LVG views, there were the statistically significant differences in the paced QRS duration values in all areas except the apex area. (LV mid-anterior: 147 ± 11 ms vs LV base: 127 ± 13 ms, P < 0.001, and vs LV mid-septum: 129 ± 12 ms, P = 0.001, respectively.) CONCLUSIONS: Cardiac angiography showed that there was a relationship between the anatomical right ventricular pacing site and paced QRS duration. Cardiac angiography can help determine the areas that produce shorter paced QRS duration.

Speckle reduction mechanism in laser rear projection displays using a small moving diffuser.

Recently, a practical method of speckle reduction in laser rear projection displays that uses an optical system with a small moving diffuser has attracted much attention. In this paper, a model of the speckle generation and reduction mechanism in the system is presented. We investigated the speckle, focusing on the physical aspects of its generation, rather than treating it statistically. We found that the granularity of the speckle patterns generated by the small diffuser corresponded to the size of the coherent regions on the projection screen. This determined the efficiency of the speckle reduction when the small diffuser was rotated.

Double target method (double marker-guided extrathoracic introducer insertion).

Incidence of damage to pacemaker and implantable cardioverter defibrillator leads is an emerging problem that should be prevented. The extrathoracic venipuncture approach has been suggested as a technique for venous access to avoid the problem. This report describes the method of double marker-guided venipuncture of extrathoracic subclavian and/or axillary vein. This approach achieves definite, safe, and speedy extrathoracic venipuncture and may be especially suitable for multiple lead placement for cardiac resynchronization therapy.