Cardiomyocyte progenitors in a canine pulmonary vein model of persistent atrial fibrillation.

BACKGROUND: This study aimed to discover the pathogenesis of focal atrial fibrillation (AF) originating from pulmonary veins by observing the histological structure and special cells in the canine pulmonary vein model of persistent atrial fibrillation. METHODS: The pulmonary veins and the sinus node were obtained from 10 mongrel dogs (5 AF and 5 control group). Light microscopy, transmission electron microscopy, and immunohistochemistry were applied to transverse sections of each pulmonary vein and sinoatrial node. Morphological and distribution analyses were performed manually and automatically. RESULTS: Cardiomyocyte progenitor (CMPs) and interstitial cells of Cajal (ICCs) showing typical features of either very immature or developing cells were found in the pulmonary vein sections of all animals subjected to experimental AF but not in the control group. The cells were mainly identified in sections with a thick muscular sleeve. A positive immunostaining of CMPs was also demonstrated; the staining characteristic was similar to that of P cells in the sinoatrial node, suggesting that these cells may function in a pacemaker capacity. CONCLUSIONS: We demonstrated that pulmonary veins can host cardiac stem cell niches. Continuous rapid pacing can induce the differentiation of CMPs and ICCs, and CMPs may underlie the pacemaker activity of isolated pulmonary veins.

The effect of early and intensive statin therapy on ventricular premature beat or nonsustained ventricular tachycardia in patients with acute coronary syndrome.

BACKGROUND: To evaluate the prognostic value of early and intensive lipid-lowering treatment on ventricular premature beat or nonsustained ventricular tachycardia (NSVT) after acute coronary syndrome (ACS) (ST-elevation myocardial infarction [STEMI], non-STEMI, and unstable angina pectoris). HYPOTHESIS: Provided that early and intensive lipid-lowering treatment can reduce ventricular premature beat or non-sustained ventricular tachycardia after ACS. METHODS: A total of 586 patients with ACS were randomly divided into 2 groups: group A (with conventional statin therapy, to receive 10 mg/day atorvastatin, n = 289) and group B (early and intensive statin therapy, 60 mg immediately and 40 mg/day atorvastatin, n = 297). The frequency of ventricular premature beat and NSVT was recorded with Holter monitoring after hospitalization (24 hours and 72 hours). RESULTS: Seventy-seven (11.8%) patients had NSVT. When compared to patients with no documented NSVT, patients with NSVT were older and more often had myocardial infarction, diabetes mellitus, atrial fibrillation, and an ejection fraction < 40% in their history. Ventricular premature beats decreased significantly in the early and aggressive treatment group (24 hours, P < 0.01; 72 hours, P < 0.001). A significant reduction in NSVT was seen in the early and aggressive (24 hours, P < 0.01; 72 hours, P < 0.001) group. No side effects were observed in either group. CONCLUSIONS: Early and intensive lipid-lowering treatment can obviously decrease ventricular premature beats and NSVT.

The effect of early and intensive statin therapy on ventricular premature beat or non-sustained ventricular tachycardia in patients with acute coronary syndrome.

BACKGROUND: Our study's aim was to evaluate the prognostic value of early and intensive lipid-lowering treatment on ventricular premature beat or non-sustained ventricular tachycardia (NSVT) after acute coronary syndrome (STEMI, non-STEMI, and unstable angina pectoris). METHODS: Some 586 patients with acute coronary syndrome were randomly divided into two groups: Group A (with conventional statin therapy, to receive 10 mg/day atorvastatin, n = 289) and Group B (given early and intensive statin therapy, 60 mg immediately and 40 mg/day atorvastatin, n = 297). The frequency of ventricular premature beat and NSVT was recorded via Holter monitoring after hospitalization (24 h and 72 h). RESULTS: Seventy seven (11.8%) patients had NSVT. When compared to patients with no documented NSVT, patients with NSVT were older and more frequently had myocardial infarction in their history, diabetes mellitus, atrial fibrillation and an ejection fraction < 40%. Ventricular premature beats decreased significantly in the early and aggressive treatment group (24 h, p < 0.01; 72 h, p < 0.001). A significant reduction in NSVT was seen in the early and aggressive treatment group (24 h, p < 0.01; 72 h, p < 0.001). There were no side effects observed in either group. CONCLUSIONS: Early and intensive lipid-lowering treatment can clearly decrease ventricular premature beats and NSVT.