Takanori Yaegashi

Short-term rapid atrial pacing alters the gene expression profile of rat liver: Cardiohepatic interaction in atrial fibrillation

BACKGROUND Atrial fibrillation (AF) activates the coagulation system, leading to hypercoagulation of the blood. The liver is a major source of prothrombotic molecules. OBJECTIVE This study aimed to clarify whether cardiohepatic interactions are involved in AF-related hypercoagulation. METHODS We compared gene expression profiles of human liver tissue between patients with AF and sinus rhythm. An AF model was created by rapid atrial pacing (RAP) at a frequency of 1200 beats/min in anesthetized 10-week-old Sprague-Dawley rats. Livers, atria, and peripheral blood cells were collected and analyzed after 12 hours of RAP. RESULTS DNA microarray analysis revealed marked changes in the gene expression profile of human liver of patients with AF. The extrinsic prothrombin activation pathway showed the most prominent change in 354 BioCarta pathways. Twelve hours of RAP also markedly altered the gene expression profile of rat liver. RAP markedly augmented the hepatic messenger RNA expression of fibrinogen chains, prothrombin, coagulation factor X, and antithrombin III. The augmented fibrinogen production by RAP was accompanied by increased of interleukin 6 (IL-6) messenger RNA expression in peripheral blood cells, enhanced monocyte chemoattractant protein-1 expression in the liver, infiltrated cluster of differentiation 11b-positive mononuclear cells in the liver, and enhanced signal transducer and activator of transcription 3 (STAT3) phosphorylation in the nuclei of hepatocytes. STAT3 phosphorylation and increased fibrinogen and coagulation factor X production by RAP were suppressed by pretreatment with IL-6 neutralizing antibody. CONCLUSION Rapid atrial excitation mimicking paroxysmal AF remotely altered the hepatic gene expression of prothrombotic molecules. Increased fibrinogen expression in the liver by RAP was mediated by activation of the IL-6/STAT3 signaling pathway in the peripheral blood and liver.

Impact of left atrial size on isolation area in the acute phase of pulmonary vein isolation using 28 mm cryoballoon

The impact of left atrial (LA) size on isolation area (ISA) using a 28‐mm second‐generation cryoballoon (CB) in the acute phase after pulmonary vein isolation (PVI) and the differences of CB from contact force‐guided radiofrequency (RF) ablation have not been fully investigated.

Separated right and left ventricular excitation during right ventricular septal pacing in a patient with narrow QRS wave: a case report.

IntroductionRight ventricular septal pacing is thought to be better than right ventricular apical pacing for shortening the QRS duration and for preserving left ventricular function. However, right ventricular septal pacing may not be effective in all cases. In this case report, we present a rare case in which right ventricular septal pacing induced thoroughly separated right and left ventricular excitation despite the presence of a relatively narrow QRS wave during atrium-only pacing.Case presentationWe report a case of 63-year-old Japanese man with cardiomyopathy with an implantable cardioverter defibrillator placement for ventricular tachycardia. Three years after implantation, he developed second-degree atrio-ventricular block. Therefore, atrio-ventricular sequential pacing was started; then his heart failure was much worsened. His electrocardiogram showed a dissociated biphasic QRS wave during right ventricular high-septal pacing, despite the presence of a non-fragmented QRS morphology during atrium-only pacing. An activation map during right ventricular high-septal pacing showed that right ventricular conduction started at the pacing site and ended at the right ventricular basal inferior site. Subsequently after a 10ms interval, left ventricular conduction started at the left ventricular posteroseptum and ended at the left ventricular lateral wall. These data indicate that during right ventricular high-septal pacing, the first component of the QRS wave supposedly reflects only right ventricular excitation and the second component only left ventricular excitation. Also due to the intracardiac electrograms, it was assumed that this phenomenon was caused by transversely limited severe transseptal conduction disturbance.ConclusionIt should be noted that even ventricular septal pacing could evoke harmful interventricular dyssynchrony due to transversely limited severe septal conduction disturbance, despite the presence of a relatively narrow QRS wave.