Optimal Force–Time Integral for Pulmonary Vein Isolation According to Anatomical Wall Thickness Under the Ablation Line

13301甲第4497号博士（医学）金沢大学博士論文要旨Abstract 以下に掲載：Journal of the American Heart Association 5(3) pp.e003155 2016. Wiley. 共著者：Chikata, Akio, Takeshi Kato, Satoru Sakagami, Chieko Kato, Takahiro Saeki, Keiichi Kawai, Shin-ichiro Takashima, Hisayoshi Murai, Soichiro Usui, Hiroshi Furusho, Shuichi Kaneko, Masayuki Takamur

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

Introduction. Right 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 presentation. We 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. Conclusion: It 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. © 2014 Yaegashi et al.; licensee BioMed Central Ltd

Adaptive cardiac resynchronization therapy for dilated cardiomyopathy with functional mitral regurgitation

We report the case of a man in his 60s who had dilated cardiomyopathy with severe functional mitral regurgitation. Four years after a cardiac resynchronization therapy (CRT) device with an implantable cardioverter defibrillator was implanted, this device was replaced with an adaptive CRT device because of battery consumption. Seven months after replacement of this device, the left ventricular pacing to right ventricular activation and the atrioventricular delay from automatic adjustments contributed to less functional mitral regurgitation. The findings from our case suggest that optimal CRT, by measuring intracardiac conduction parameters, is effective for functional mitral regurgitation

Magnetic resonance imaging in a patient with an implantable cardiac defibrillator

A 58-year-old man, in whom an implantable cardiac defibrillator (ICD) had been implanted for Brugada syndrome, suffered rapidly progressive general paralysis. Various diagnostic imaging techniques were performed, but the cause could not be determined. Magnetic resonance imaging (MRI) scanning was performed. A 1.5-Tesla MRI system was used, and the ICD was programmed to ODO mode and all tachycardia detection was turned off. MRI was performed safely under electrocardiogram and pulse oximeter monitoring, and appropriate precautions were taken in preparation for an emergency. ICD parameters did not change in post-imaging investigations. MRI revealed an apparent tumor in the patient's medulla and upper cervical spinal cord, which was diagnosed as high-grade astrocytoma. When performing MRI procedures in patients with an ICD under urgent conditions, it is necessary to have complete knowledge of the procedure and to make careful preparations