Mexiletine Shortened QT Interval and Reduced Ventricular Arrhythmias in a Pedigree of Type 2 Long QT Syndrome Combined with Left Ventricular Non-Compaction

Curative Effect of Yangxin Dingji Capsule Combined With Mexiletine Hydrochloride on Postoperative Arrhythmia and Its Influences on the Vascular Endothelial Function in Coronary Bifurcation Lesions

Objective

The aim of the study is to explore the curative effect of Yangxin Dingji capsule combined with mexiletine hydrochloride on postoperative ventricular arrhythmia (VA) and its influences on vascular endothelial function in coronary bifurcation lesions (CBL).

Methods

A total of 110 patients with CBL admitted to the hospital were enrolled as research subjects between January and December 2021. According to the random number table method, they were divided into a combination group and control group, with 55 cases in each group. The control group was treated with mexiletine hydrochloride, while the combination group was additionally treated with Yangxin Dingji capsules. All were continuously treated for 4 weeks. The clinical response rate between the two groups was compared. The frequencies of 24 h paroxysmal atrial fibrillation, premature atrial contraction, and premature ventricular contraction were compared by the Holter monitoring. The whole blood low-shear viscosity, whole blood high-shear viscosity, and fibrinogen (Fb) in both groups were measured by a full-automatic blood flow analyzer. The levels of plasma nitric oxide (NO), endothelin-1 (ET-1), and von Willebrand factor (vWF) were detected by the nitrate reductase method and enzyme-linked immunosorbent assay (ELISA). During treatment, the occurrence of adverse reactions (vomiting, loss of appetite, dry mouth, diarrhea, nausea) in both groups was statistically analyzed.

Results

After treatment, the total response rate of treatment in the combination group was significantly higher than that in the control group (P < 0.05). After treatment, frequencies of paroxysmal atrial fibrillation, premature atrial contraction, and premature ventricular contraction in the combination group were significantly lower than those in the control group (P < 0.05). Whole blood low-shear viscosity, whole blood high-shear viscosity, and the Fb level were significantly lower than those in the control group (P < 0.05). After treatment, the NO level in the combination group was significantly higher than that in the control group (P < 0.05), while levels of ET-1 and vWF were significantly lower than those in the control group (P < 0.05). During treatment, there was no significant difference in the total incidence of adverse reactions between the two groups (P > 0.05).

Conclusion

Yangxin Dingji capsule combined with mexiletine hydrochloride can significantly improve clinical effects in CBL patients, improve VA and vascular endothelial function, and reduce plasma viscosity without increasing the incidence of adverse reactions.

Long QT syndrome and left ventricular non-compaction in a family with KCNH2 mutation: A case report

BACKGROUND

Left ventricular non-compaction (LVNC) is an abnormality of the myocardium, characterized by prominent left ventricular trabeculae and deep inter-trabecular recesses. Long QT syndrome (LQTS) is a cardiac ion channelopathy presenting with a prolonged QT interval on resting electrocardiogram and is associated with increased susceptibility to sudden death. The association between LVNC and LQTS is uncommon.

CASE PRESENTATION

We report an Italian family with a novel pathogenic KCNH2 variant who presented with clinical features of LVNC and LQTS. The proband came to our attention after two syncopal episodes without prodromal symptoms. His ECG showed QTc prolongation and deep T wave inversion in anterior leads, and the echocardiogram fulfilled LVNC criteria. After that, also his sister was found to have LQTS and LVNC, while his father only presented LQTS.

CONCLUSIONS

Physicians should be aware of the possible association between LVNC and LQTS. Even if this association is rare, patients with LVNC should be investigated for LQTS to prevent possible severe or even life-threatening arrhythmic episodes.

Overlap phenotypes of the left ventricular noncompaction and hypertrophic cardiomyopathy with complex arrhythmias and heart failure induced by the novel truncated DSC2 mutation

Background

The left ventricular noncompaction cardiomyopathy (LVNC) is a rare subtype of cardiomyopathy associated with a high risk of heart failure (HF), thromboembolism, arrhythmia, and sudden cardiac death.

Methods

The proband with overlap phenotypes of LVNC and hypertrophic cardiomyopathy (HCM) complicates atrial fibrillation (AF), ventricular tachycardia (VT), and HF due to the diffuse myocardial lesion, which were diagnosed by electrocardiogram, echocardiogram and cardiac magnetic resonance imaging. Peripheral blood was collected from the proband and his relatives. DNA was extracted from the peripheral blood of proband for high-throughput target capture sequencing. The Sanger sequence verified the variants. The protein was extracted from the skin of the proband and healthy volunteer. The expression difference of desmocollin2 was detected by Western blot.

Results

The novel heterozygous truncated mutation (p.K47Rfs*2) of the DSC2 gene encoding an important component of desmosomes was detected by targeted capture sequencing. The western blots showed that the expressing level of functional desmocollin2 protein (~ 94kd) was lower in the proband than that in the healthy volunteer, indicating that DSC2 p.K47Rfs*2 obviously reduced the functional desmocollin2 protein expression in the proband.

Conclusion

The heterozygous DSC2 p.K47Rfs*2 remarkably and abnormally reduced the functional desmocollin2 expression, which may potentially induce the overlap phenotypes of LVNC and HCM, complicating AF, VT, and HF.