Genetic Mechanisms Contribute to the Development of Heart Failure in Patients with Atrioventricular Block and Right Ventricular Apical Pacing.

Right ventricular apical (RVA) pacing can lead to progressive left ventricular dysfunction and heart failure (HF), even in patients with normal cardiac structure and function. Our study conducted candidate gene screening and lentivirus transfected neonatal rat cardiomyocytes (NRCMs) to explore the genetic and pathogenic mechanisms of RVA pacing induced cardiomyopathy in third degree atrioventricular block (III AVB) patients. We followed 887 III AVB patients with baseline normal cardiac function and RVA pacing. After a median follow-up of 2.5 years, 10 patients (four males, mean age 47.6 ± 10.0 years) were diagnosed with RVA pacing induced HF with left ventricular ejection fraction (LVEF) reducing dramatically to 37.8 ± 7.1% (P < 0.05). Candidate genes sequencing found cardiomyopathy associated genetic variations in all ten HF patients and six SCN5A variations in 6 of 20 control patients. Transfected NRCMs of Lamin A/C mutations (R216C and L379F) disrupted Lamin A/C location on nucleus membrane and finally resulted in increased apoptotic rate after serum starvation. In conclusion, cardiomyopathy associated genetic variations play an essential role in occurrence of newly onset HF in the III AVB patients with RVA pacing. RVA pacing, serving as extra stimulator, might accelerate the deterioration of cardiac structure and function.

[Management of refractory ventricular tachycardia in patients with non-myxomas primary cardiac tumors].

OBJECTIVE: To summarize the clinical characteristics and treatment experience of patients with non-myxomas primary cardiac tumors accompanied with refractory ventricular tachycardia (VT). METHODS: Clinical and imaging data as well as therapy efficacy and outcome were analyzed in 10 patients with non-myxomas primary cardiac tumors accompanied with refractory VT. RESULTS: There were 5 male and 5 female patients in this cohort [mean age (37.6±18.2) years]. Palpitation was presented in all 10 patients, 7 patients experienced syncope, and 2 patients suffered from amaurosis. The diagnosis was made by combined use of transthoracic echocardiograms, MRI, and CT scan. The time from symptom to diagnosis was (33.2±36.7) months. Symptom-related VT was documented by ECG or Holter monitoring. MRI suggested lipoma in 7 patients, lymphoma in 1 patient and fibroma in another patient. Seven tumors were located in the left ventricle, 1 in right atria, 1 at peri-aortic root and 1 near right ventricular outflow tract. Nine out of 10 patients received anti-arrhythmic drug therapy. The ventricular tachyarrhythmia disappeared after surgical tumor resection in 4 patients. All other patients who were treated with antiarrhythmic drugs, radiofrequency ablation or subtotal excision showed only suboptimal efficacy during (39.4±25.1) months follow-up. CONCLUSION: Surgical tumor removal is the best treatment strategy for the treatment of refractory ventricular tachycardia in patients with primary cardiac benign tumors.

[Clinical characteristics and outcome of 32 patients with long-QT syndrome accompanied with torsade de pointes].

OBJECTIVE: To summarize the clinical characteristics and outcome of patients with long-QT syndrome (LQTs) accompanied with torsade de pointes. METHODS: Thirty-two eligible patients were included in this study. Clinical and electrocardiographic data were analyzed and telephone or out-patient follow-up were made in all patients. RESULTS: There were 15 patients with inherited LQTs (h-LQTs) and 17 patients with acquired LQTs (a-LQTs). There are more women (n = 24) than men (n = 8). ß blockers, potassium and magnesium supplement were the basic therapy for h-LQTs patients, bivent pacemaker was implanted in 2 patients and implantable cardioverter defibrillator was implanted in 5 patients. Ventricular tachyarrhythmias and syncope occurred in 4 patients during (39.4 ± 25.1) months follow-up. In 17 a-LQTs patients, one patient with dilated cardiomyopathy died suddenly and another patient with implanted cardioverter defibrillator experienced one ventricular tachycardia during (30.9 ± 13.3) months follow-up. CONCLUSIONS: The prognosis in h-LQTs and a-LQTs patients with structure heart disease is poor. ICD or CRT-D therapy is suggestive for a-LQTs patients with structure heart disease.