Clinical characterization and outcome of patients with noncompaction of ventricular myocardium / 中华心血管病杂志

<p><b>OBJECTIVE</b>To analyze the clinical features and outcome of patients with noncompaction of ventricular myocardium (NVM).</p><p><b>METHODS</b>Clinical manifestations, electrocardiograms and echocardiographies data were analyzed in 18 patients with NVM. Mean follow-up period was (11 +/- 5) months.</p><p><b>RESULTS</b>The patients aged from 1.5 to 71 years, 66.7% patients were males, familial history was observed in 2 cases, congestive heart failure was present in 14 cases, thromboembolic event occurred in 1 patient, arrhythmia induced syncopes were diagnosed in 2 patients and 1 patient was asymptomatic. Abnormal electrocardiograms were observed in all patients, including premature ventricular beats (7 cases), heart block (4 cases), and atrial fibrillations (4 cases). Echocardiographies showed that noncompaction of ventricular myocardium localized in the left ventricle in 17 patients, and right ventricle in 1 patient. The extension of noncompaction myocardium was predominantly at the apex (72%). N/C was 2.3 - 3.1. EF was less than 50% in 15 patients. Hypokinetic movements were observed in both noncompacted and compacted segments. During the follow-up, 1 patient with congestive heart failure received heart transplantation. ICD was implanted in one patient due to ventricular tachycardia. One patient suffered from sudden cardiac death.</p><p><b>CONCLUSIONS</b>The most common clinical presentations of NVM are congestive heart failure, cardiac arrhythmias, and thromboembolism. Echocardiography is considered as the best tool for the diagnosis of NVM. ICD, heart transplantation and anticoagulation therapy could improve the prognosis of patients with NVM in selected cases.</p>

Effect of imidapril on the effective refractory period and sodium current of ventricular noninfarction zone in healed myocardial infarction / 药学学报

<p><b>AIM</b>To investigate the effects of imidapril (IMI) on effective refractory period (ERP) and sodium current (I(Na)) of myocytes in ventricular noninfarction zone of healed myocardial infarction (HMI) in rabbit models.</p><p><b>METHODS</b>Rabbits with left coronary artery ligation were prepared and IMI (0.625 mg x kg(-1) x d(-1), 8 weeks) was orally administered. The ERP and sodium current were recorded.</p><p><b>RESULTS</b>The ERP in HMI heart was prolonged. The ERP in IMI group was lower significantly than that of HMI group. The I(Na) density of myocyte in HMI ventricle decreased obviously. V 1/2 of steady state inactivation of I(Na) shifted to hyperpolarization, and time constant (tau) of recovery from inactivation in HMI ventricular myocyte was longer than that of sham ventricular myocyte. I(Na) density in IMI group increased markedly as compared with that of HMI group.</p><p><b>CONCLUSION</b>IMI was shown to reverse the abnormal prolongation of ERP in rabbit heart with the HMI and increase I(Na) density. It may be the mechanism of IMI preventing against antiarrhythmia in healed myocardical infarction.</p>

Effects of transforming growth factor-beta1 and signal protein Smad3 on rat cardiomyocyte hypertrophy / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>SMAD proteins have recently been identified as the first family of putative transforming growth factor-beta1 (TGF-beta1) signal transducers. This study was to investigate the effects of TGF-beta1 and signal protein Smad3 on rat cardiac hypertrophy.</p><p><b>METHODS</b>The incorporation of [(3)H]-leucine was measured to determine the hypertrophy of cardiomyocyte incubated with different doses of TGF-beta1 in cultured neonatal cardiomyocytes. The model of rat cardiac hypertrophy was produced with constriction of the abdominal aorta. At different times after the operation, rats were killed, and their left ventricular mass index (LVMI) determined. The mRNA expression of TGF-beta1 and Smad3 of cultured cells and hypertrophic left ventricles were assessed by RT-PCR. The protein expression of Smad3 was assessed by Western blot.</p><p><b>RESULTS</b>In cultured neonatal cardiomyocytes, TGF-beta1 significantly promoted incorporation of [(3)H]-leucine. With the concentration of 3 pg/L, it increased the expression of Smad3 in mRNA and protein levels after 15 minutes, and continued for up to 8 hours of cultured cardiomyocytes. The LVMI and the expression of TGF-beta1 (mRNA) and Smad3 (mRNA and protein) of hypertrophic left ventricle were increased by day 3 after the operation and continued to the 4th week. The peak expression of these was in the second week after operation.</p><p><b>CONCLUSION</b>TGF-beta1 has positive effects on rat cardiomyocyte hypertrophy. Signal protein Smad3 could be related to the pathologic progression of rat cardiac hypertrophy.</p>

Heterogeneity of action potential and ion currents in the left ventricular myocytes of the rabbit / 生理学报

Experiments were performed to investigate the heterogeneity of the action potential and ion currents in left ventricular myocytes of the rabbit. Myocytes were isolated by enzymatic method. The sub-endocardial (Endo) and sub-epicardium (Epi) tissues were separated from the other region (midmyocardium, M) with a razor. Single cells in each region were obtained by gentle shaking and dispersing in a chamber filled with normal Tyrode's solution. The results showed that the action potential and the ion currents in the three layers were significantly different. M cells had a more pronounced spike-and-dome configuration, with a significantly larger phase 1 magnitude and plateau voltage. Action potential duration (APD) in M cells was longer than that in Epi or Endo cells. I(Ca, L) and I(to) in M cells were higher than those of Epi and Endo. On the contrary, I(K,s) in M cells was the minimum compared with those in the three LV walls. The differences in ion currents may well explain the heterogeneity of action potentials in M layers of the rabbit heart.