Yoshihiko Sakai

Effects of losartan on serum total and high-molecular weight adiponectin concentrations in hypertensive patients with metabolic syndrome

High-molecular weight (HMW) adiponectin may have the most biologic activity among several isoforms. We investigated long-term effects of losartan on serum concentrations of total and HMW adiponectin in hypertensive patients with metabolic syndrome (MS) by serial measurements over 6 months. Forty hypertensive patients first received 50 mg of losartan. Upward titration of the losartan dose was implemented to reach a target blood pressure of less than 140/90 mm Hg. Serum total adiponectin and HMW adiponectin were measured at study entry (baseline), the 3-month treatment time point, and the end of the 6-month period. Non-HMW adiponectin (ie, medium- and low-molecular weight adiponectin) was calculated as total adiponectin--HMW adiponectin. Diagnosis of MS was done by current standard criteria. In hypertensive patients without MS (n = 21), the serum total adiponectin increased from 9.8 +/- 5.4 microg/mL at baseline to 11.1 +/- 6.2 microg/mL at 6 months (P < .01). Furthermore, the serum total adiponectin was significantly higher at 6 months than at 3 months (P < .01). Serum HMW adiponectin also increased from 5.7 +/- 3.9 microg/mL at baseline to 6.6 +/- 4.4 microg/mL at 6 months (P < .01). In hypertensive patients with MS, the serum total adiponectin increased from 6.0 +/- 2.7 mug/mL at baseline to 6.7 +/- 3.3 microg/mL at 3 months and to 7.0 +/- 3.1 microg/mL at 6 months (P < .01 for both). Furthermore, the serum HMW adiponectin concentration was significantly higher at 6 months than at 3 months (P < .001). However, the serum non-HMW adiponectin concentration did not change during treatment in either group. In conclusion, serum total and HMW adiponectin concentrations increase after 6 months of losartan treatment in hypertensive patients, irrespective of the presence or absence of MS.

The influence of the external structures in atrial fibrillation patients: Relationship to focal low voltage areas in the left atrium.

INTRODUCTION Left atrial (LA) low voltage areas (LVAs) are suggested as an important factor for maintaining atrial fibrillation (AF). The relationship between focal LVAs and anatomical contact is still unclear. METHODS Thirty paroxysmal AF (PAF) and 30 persistent AF (PsAF) patients underwent high density voltage mapping during sinus rhythm before any radiofrequency applications were performed. The relationship between the LVA (<0.5mV) and contact area (CoA) demonstrated by enhanced CT and the distance to near external structures were investigated. RESULTS The anterior region, posterior wall and left pulmonary vein (LPV) antrum were the three most frequent LVA sites that corresponded to CoA sites, and LVAs mostly overlapped with CoAs (PAF 47/61: 77%, PsAF 63/74: 85%). In the PAF group, patients with posterior-LVAs had a shorter distance to the vertebrae than those without (2.8 ± 1.1 vs. 4.4 ± 1.9 mm; P=0.0086). The distance to the vertebrae was the only predictive factor of the existence of a posterior-LVA and the cut-off value was ≤2.9 mm (P<0.0001). Similarly, an LPV-LVA also had the same results (2.0 ± 0.5 vs. 2.7 ± 0.8mm, P=0.0127) and the cut-off value was ≤2.6mm (P=0.0391). In contrast, the PsAF patients had no difference in the distance when compared to the existence of an LVA. CONCLUSIONS Anatomical CoAs demonstrated a spatial relationship to the LVAs in AF patients. In PAF patients, the distance to near external structures in the posterior region was a predictive factor for the existence of an LVA and may have had some influence on maintaining AF, while in PsAF patients no relationship was suggested.

Epicardial adipose tissue-based defragmentation approach to persistent atrial fibrillation: Its impact on complex fractionated electrograms and ablation outcome

BACKGROUND Increased epicardial adipose tissue (EAT) volume is associated with atrial fibrillation (AF). However, the efficacy of EAT-based left atrial (LA) ablation for persistent AF (PsAF) is unclear. OBJECTIVE The purpose of this study was to assess whether EAT-based LA ablation is effective for PsAF. METHODS In 60 PsAF patients (group I), 3-dimensional reconstructed computed tomography images depicting EAT were merged with NavX-based dominant-frequency (DF) and complex fractionated electrogram (CFE) maps obtained during AF. Pulmonary vein antrum isolation (PVAI) was followed by map-guided EAT-based ablation. Results were compared to those in a historical control group (group II, case-matched patients who underwent generalized stepwise ablation including linear plus CFE-targeted ablation). RESULTS In 70% (n = 42) of group I patients, the LA-EAT was located at the pulmonary vein antra; anterior and inferior surfaces, roof, septum, and mitral annulus; and left atrial appendage. EAT was at or near (<3 mm) 71% (390/550) of high-DF (> -8 Hz) sites. In 41 patients with persistent AF despite EAT-targeted ablation, CFE burden decreased significantly (from 96% to 13%, P < .0001), and DF decreased within the coronary sinus (6.9 ± 0.7 Hz vs 5.9 ± 0.7 Hz, P < .0001). Radiofrequency energy duration was significantly less in group I than in group II (25 ± 6 minutes vs 31 ± 12 minutes, P < .05). During 16-month follow-up, freedom from AF on antiarrhythmic drugs was 78% vs 60% (P < .05). CONCLUSION PVAI plus EAT-based ablation efficiently eliminates high-frequency sources and yields relatively high success. EAT-based LA ablation is a simple, clinically feasible PsAF ablation strategy.

Strong modulation of ectopic focus as a mechanism of repetitive interpolated ventricular bigeminy with heart rate doubling

BACKGROUND Repetitive interpolated ventricular bigeminy (RIVB) can introduce a doubling of the ventricular rate. OBJECTIVE To clarify the mechanism of RIVB, we hypothesized that it was introduced by a strong modulation of the ventricular automatic focus. METHODS RIVB, defined as more than 7 bigeminy events, was detected by instantaneous heart rate and bigeminy interval (BI) tachograms in 1450 successive patients with frequent ventricular premature contractions (≥3000 per day). Postextrasystolic interval bigeminy interval curves were plotted to determine the degree of modulation. Mean sinus cycle length bigeminy interval curves were plotted for selection. RIVB was simulated by using a computer-based parasystole model. RESULTS RIVB was observed in 7 patients (age 60 ± 16 years; 2 men and 5 women) with a heart rate of 58.2 ± 6.5 beats/min during a rest period both during the day and at night. The tachograms disclosed the onset of the RIVB with a doubled ventricular rate to 112.3 ± 8.5 beats/min. On the postextrasystolic interval bigeminy interval curves, compensatory bigeminy and interpolated bigeminy constituted overlapping regression lines with slopes close to 1.00 and RIVB was located in the lower left portion. RIVB lasting for up to 3 hours was quickly detected by mean sinus cycle length bigeminy interval curve. The PQ interval immediately after RIVB was prolonged in comparison with baseline (0.18 ± 0.02 to 0.21 ± 0.02 seconds; P < .001). The simulation was able to reproduce RIVB faithfully at a slow heart rate. CONCLUSIONS Our findings support the hypothesis that RIVB was introduced by strongly modulated ventricular pacemaker accelerated by an intervening normal QRS.

Impact of catheter tip-tissue contact on three-dimensional left atrial geometries: Relationship between the external structures and anatomic distortion of 3D fast anatomical mapping and high contact force guided images.

BACKGROUND A high catheter tip-tissue contact force (CF) with the myocardium may cause 3-dimensional (3D) map distortion, however, the influence of external structures surrounding the left atrium (LA) on that distortion remains unknown. This study characterized the impact of high CF mapping on the local LA geometry distortion. METHODS Thirty AF patients underwent 3D-ultrasound merged with CT images (3D-Merge-CT). The LA area in contact with external structures was identified by enhanced CT. Fast-electroanatomical-mapping (FAM) geometries were created by two methods, point-by-point mapping with high (>10g) CFs (high-CF guided-FAM), followed by that with multielectrode-mapping catheters (conventional-FAM). The resulting geometries were compared with the 3D-Merge-CT images. RESULTS Three representative anatomical contact areas (ascending aorta-vs.-anterior wall, descending aorta-vs.-left pulmonary vein [PV], and vertebrae-vs.-posterior wall) were identified. The PV antrum distorted distance on the 3D-Merge-CT was significantly longer for high-CF guided-FAMs than conventional-FAMs (1.7[0-3.6] vs. 0[0-1.8]mm, P<0.0001). In high-CF maps, the distorted distance significantly differed between regions with and without contact areas in both the PV antrum (0[0-0.17] vs. 1.7[0-3.9]mm, P=0.0201) and LA body region (0[0-1.5] vs. 1.7[0.7-2.2]mm, P<0.005). The catheter tip-tissue CF did not correlate with the distorted distance (r=0.08, P=0.46), and a multivariate analysis revealed that the absence of anatomical contact areas was strongly associated with significant local distortion, independent of the CF. CONCLUSIONS High-CF guided mapping yields greater 3D-image anatomical distortion than conventional-FAM methods. That distortion was attenuated by regions with anatomical contact areas, suggesting that regional anatomic distortion is involved in the existence of external structures surrounding the LA.

Insulin Resistance as a Predictor of the Late Catch-up Phenomenon After Drug-Eluting Stent Implantation

BACKGROUND Percutaneous coronary intervention (PCI) is an effective treatment for patients with ischemic heart disease. In particular, restenosis is suppressed after drug-eluting stent (DES) implantation. However, several problems remain. Previously, we reported neointimal proliferation after DES implantation, which was associated with insulin resistance (IR). The aim of the present study was to clarify whether IR is associated with mortality and major adverse cardiac and cerebrovascular events (MACCE) after 1st-generation DES implantation. METHODSANDRESULTS We researched the clinical records of 109 patients who had undergone elective PCI and DES implantation between May 2007 and December 2010. We segregated these patients according to the value of the homeostasis model assessment of IR (HOMA-IR) into Group P (n=63; HOMA-IR ≥2.5, positive) and Group N (n=46; HOMA-IR <2.5, negative), and examined the relationship between HOMA-IR and MACCE. The observation period was 7.4±1.6 years. There were no differences between the 2 groups in the occurrence of all-cause death, cardiac death, restenosis, myocardial infarction, stroke, heart failure, or stent thrombosis. However, the late catch-up phenomenon was significantly more common in Group P than in Group N (12.7% vs. 2.2% P=0.048). CONCLUSIONS IR is a useful predictor of the late catch-up phenomenon after DES implantation, and improvement of IR may help to prevent the phenomenon. (Circ J 2016; 80: 657-662).

A unique iatrogenic organized left atrial tachycardia with a gap conduction in previously ablated lesions.

This case concerns a 57-year-old woman with an organized left atrial tachycardia (AT) after pulmonary vein (PV) isolation. The left inferior PV (LIPV) exhibited a figure of eight tachycardia around the LIPV ostium with one loop at the anterior aspect and another at the posterior aspect, which corresponded to regular surface P waves. Although a gap ablation of fractionated electrograms changed the LIPV sequence, the atrial potentials were organized with a shortened cycle length accompanied by the same surface P-wave morphology. The elimination of the anterior loop and modification of the posterior loop after the gap ablation might have yielded that specific sequence change of the AT.

Mechanism of Ventricular Premature Contraction Showing Interpolated Bigeminy —Strong Modulation Hypothesis—

Recent advances in invasive electrocardiology dramatically revealed the unique nature of atrial fibrillation originating from the pulmonary veins. By the same invasive technique, the origin of ventricular premature contraction (VPC) has been clarified as being located in the pulmonary outflow tract, ventricular Purkinje fibers or coronary cusps. Despite these clarifications, the essential mechanism of VPCs still remains uncertain. In addition to automaticity, the possible contribution of reentrant pathway cannot be fully ruled out. To analyze the mechanism, we previously reported on a two dimensional color display of interectopic intervals in VPC patients. This display could estimate the fundamental mechanism of VPC for a full day and clearly differentiate parasystole from fixed coupling interval VPCs.

Influence of the left atrial contact areas on fixed low-voltage zones during atrial fibrillation and sinus rhythm in persistent atrial fibrillation: NAKAHARA et al .

Atrial low‐voltage zones (LVZ) are suggested as important factors for maintaining persistent atrial fibrillation (PsAF). The relationship between LVZs and left atrial (LA) contact areas (CoAs) is still unclear.

Coved-type ST-elevation during ablation of ischemic ventricular tachycardia

A coved‐type electrocardiogram (ECG) change in Brugada syndrome is suggested to be the result of abnormally delayed depolarization over the right ventricular outflow tract; however, ischemia of the conus branch of the right coronary artery presents the same ECG change. A 63‐year‐old man with a history of myocardial infarction demonstrated a transient coved‐type ECG change during catheter ablation of ventricular tachycardia. The ECG change appeared during left ventricular mapping without any chest symptoms, and recovered spontaneously. A pilsicainide test was negative and a coved‐type ECG did not appear during the perioperative or follow‐up period.