Abstract Introduction: Long QT Syndrome (LQTS) is an inherited disease with an abnormal electrical conduction system in the heart that can cause sudden death as a result of QT prolongation. LQT2 is the second most common subtype of LQTS caused by loss of function mutations in the potassium voltage-gated channel subfamily H member 2 (KCNH2) gene. Although more than 900 mutations are associated with the LQTS, many of these mutations are not validated or characterized. Methods and results: Sequencing analyses of genomic DNA of a family with LQT2 identified a putative mutation. i.e., KCNH2(NM_000238.3): c.3099_3112del, in KCNH2 gene which appeared to be a definite pathogenic mutation. The family pedigree information showed a gender difference in clinical features and T-wave morphology between male and female patients. The female with mutation exhibited recurring ventricular arrhythmia and syncope, while two male carriers did not show any symptoms. In addition, T-wave in females was much flatter than in males. The female proband showed a positive reaction to the lidocaine test. Lidocaine injection almost completely blocked ventricular arrhythmia and shortened the QT interval by ≥30 ms. Treatment with propranolol, mexiletine, and implantation of cardioverter-defibrillators prevented the sustained ventricular tachycardia, ventricular fibrillation, and syncope, as assessed by a 3-year follow-up evaluation. Conclusions: A putative mutation c.3099_3112del in the KCNH2 gene causes LQT2 syndrome, and the pathogenic mutation mainly causes symptoms in female progeny. Introduction (LQTS prolongation LQT voltagegated voltage gated KCNH (KCNH2 90 characterized results ie i e i.e. KCNH2NM_000238.3 KCNH2NM0002383 KCNHNM NM_000238.3 NM 000238 3 KCNH2(NM_000238.3) c30993112del cdel c 3099 3112del del Twave T wave patients syncope addition males test 30 ≥3 ms propranolol mexiletine cardioverterdefibrillators cardioverter defibrillators tachycardia fibrillation 3year year followup follow up evaluation Conclusions syndrome progeny (KCNH 9 i.e KCNH2NM KCNH2NM_000238. KCNH2NM000238 NM0002383 NM_000238. 00023 KCNH2(NM_000238.3 309 ≥ KCNH2NM_000238 KCNH2NM00023 NM000238 NM_000238 0002 KCNH2(NM_000238. KCNH2NM_00023 KCNH2NM0002 NM00023 NM_00023 000 KCNH2(NM_000238 KCNH2NM_0002 KCNH2NM000 NM0002 NM_0002 00 KCNH2(NM_00023 KCNH2NM_000 KCNH2NM00 NM000 NM_000 0 KCNH2(NM_0002 KCNH2NM_00 KCNH2NM0 NM00 NM_00 KCNH2(NM_000 KCNH2NM_0 NM0 NM_0 KCNH2(NM_00 KCNH2NM_ NM_ KCNH2(NM_0 KCNH2(NM_ KCNH2(NM

Abstract Purpose To investigate whether heat shock protein 90 (HSP90) is involved in complement regulation in ischemic postconditioning (IPC). Methods The left coronary artery of rats underwent 30 min of occlusion, followed by 120 min of reperfusion and treatment with IPC via 3 cycles of 30s reperfusion and 30s occlusion. The rats were injected intraperitoneally with 1 mg/kg HSP90 inhibitor geldanamycin (GA) after anesthesia. Eighty rats were randomly divided into four groups: sham, ischemia-reperfusion (I/R), IPC and IPC + GA. Myocardial infarct size, apoptosis index and the expression of HSP90, C3, C5a, tumor necrosis factor (TNF)-alpha, interleukin (IL)-1β and c-Jun N-terminal kinase (JNK) were assessed. Results Compared with the I/R injury, the IPC treatment significantly reduced infarct size, release of troponin T, creatine kinase-MB, and lactate dehydrogenase, and cardiomyocyte apoptosis. These beneficial effects were accompanied by a decrease in TNF-α, IL-1β, C3, C5a and JNK expression levels. However, all these effects were abrogated by administration of the HSP90 inhibitor GA. Conclusion HSP90 exerts a profound effect on IPC cardioprotection, and may be linked to the inhibition of the complement system and JNK, ultimately attenuating I/R-induced myocardial injury and apoptosis.