Yoko Hagiwara

Pulsatile Cardiac Tissue Grafts Using a Novel Three-Dimensional Cell Sheet Manipulation Technique Functionally Integrates With the Host Heart, In Vivo

We devised a method of fabricating easily transplantable scaffoldless 3D heart tissue, made with a novel cell-sheet (CS) technology from cultured cardiomyocytes using a fibrin polymer coated dish. In the present study, we tested in vivo electrical communication which is essential for improving heart function between the host heart and the grafted CS. The epicardial surface of the ventricle of an anesthetized open-chest nude rat was ablated by applying a heated metal. Bilayered CS was obtained from neonatal rat primary culture. CS was transplanted onto the injured myocardial surface (sMI) (sMI+sheet group). The rats were allowed to recover for 1 to 4 weeks, to stabilize the grafts. Action potentials (APs) from the excised perfused heart were monitored by the fluorescence signal of di-4ANEPPS with a high speed charge-coupled device camera. The APs were observed under epicardial pacing of the host heart or the CS grafts. The pacing threshold of the current output was measured in the sMI+sheet group and in the nongrafted sMI group at the center of the sMI and in the normal zone (Nz). Bidirectional AP propagation between the sMI and Nz was observed in the sMI+sheet group (n=14), but was blocked at the marginal area of the sMI in the sMI group (n=9). The ratio of the pacing threshold (sMI/Nz) was significantly lower in the sMI+sheet than in the sMI group (3.0±0.7, 19.0±6.1 respectively P<0.05). There were neither spontaneous nor pacing-induced arrhythmias in these two groups. Bidirectional smooth AP propagation between the host heart and the grafted CS was observed. This finding suggested functional integration of this CS graft with the host heart without serious arrhythmia.

Implantation of the Right Ventricular Lead of an Implantable Cardioverter-Defibrillator Complicated by Apical Myocardial Infarction

A 68-year-old man who experienced ventricular fibrillation triggered by a vasospastic angina (VSA) was resuscitated by a lay-rescuer with an automated external defibrillator. He had been diagnosed with VSA on the basis of chest pain while at rest in the early morning, which had been treated successfully with nitrates and calcium channel blockers for 13 years. During hospitalization after the patient was resuscitated, he had VSA with ST elevation in the inferior leads after cessation of both medications. Ultrasound echocardiography showed no abnormal findings after the episode of VSA. The coronary angiograph and the left ventriculograph revealed the absence of both significant coronary stenosis and segmental asynergy (Figure 1A through 1C). Figure 1. Preoperative ( A through C ) and postoperative ( D through I ) coronary angiography and left …