Effects of insulin on the QT interval and induced arrhythmias of human cardiomycytes / 西安交通大学学报(医学版)

【Objective】 To explore the effects of insulin on the QT interval and induced arrhythmias of cardiomyocytes derived from human induced pluripotent stem cells （hiPSC-CMs）. 【Methods】 Immunofluorescence staining and flow cytometry were used to analyze the purity of hiPSC-CMs. Microelectrode array （MEA） was utilized to detect the electrophysiological changes including heart rate （HR）， field potential duration （FPD， which is similar to QT interval in ECG）， FPDc （FPD corrected by HR）， conduction velocity （CV）， and spike amplitude before and after insulin treatment. The effects of E4031 on QT interval prolongation and induced arrhythmias of hiPSC-CMs were evaluated before and after treatment with insulin. 【Results】 hiPSC-CMs highly expressed myocardial specific marker cTnT. The purity of hiPSC-CMs was 97.1%. After 5-day insulin treatment of hiPSC-CMs， HR increased by （11.9±3.3）%， FPD shortened by （22.7±2.8）%， FPDc shortened by （15.6±1.6）%， and spike amplitude increased by （39.1±7.9）% when compared with untreated group， but CV remained unchanged. 10 nmol/L of E4031 could prolong the FPDc of hiPSC-CMs by （37.8±9.0）%， and 30 nmol/L of E4031 could induce arrhythmias. After insulin treatment， 10 nmol/L of E4031 prolonged the FPDc of hiPSC-CMs by （21.8±3.1）% （compared with the untreated group， insulin decreased FPDc prolongation by E4031， 37.8%±9.0% vs. 21.8%±3.1%， P<0.05）， while 30 nmol/L of E4031 did not induce arrhythmias. 【Conclusion】 Insulin can shorten the QT interval of hiPSC-CMs and significantly reduce the QT interval prolongation and the risk of arrhythmias induced by drugs.

Platypnea-orthodeoxia syndrome in a patient with a pre-existing patent foramen ovale successfully treated with an atrial septal occluder / 老年心脏病学杂志（英文版）

Platypnea orthodeoxia syndrome is associated with dyspnea and arterial oxygen desaturation accentuated by an upright posture. It can be secondary to an intracardiac shunt. We report a case of platypnea-orthodeoxia syndrome (POS) in a 58-year old male patient who had a pre-existing patent foramen ovale (PFO) and substantial pulmonary pathologies. He was successfully treated by percutaneous transcatheter closure of the PFO. Our case highlights the importance of recognition of this rare syndrome in patients who present with unexplained hy-poxia for whom transcatheter closure of the interatrial shunt can be safely carried out.