A Relationship Study On Pulmonary Vein Morphology And Histology And Atrial Fibrillation In Heart Failure

PART ITITLE A relationship study on ostia PVs morphology and AF in patients withHFOBJECTIVE The purpose of this study was to investigate the relationshipbetween ostia PVs morphology and AF in patients with HF by MDCTangiography using a new 64-slice scanner.METHODS The study included 75 patients. Group I included 35 patients withHF, group II included 19 patients with HF and chronic AF, group III included21 patients without the history of documented HF and AF. Age and concomitantheart diseases were similar among the three groups. By 64-slices MDCT withthree-dimensional reconstruction, we measured the diameter of each PV ostium atits junction with the LA in two directions (AP and SI) in addition to LA maximaltransverse, maximal AP, and SI dimensions on coronal and transverse sections.RESULTS HF with or witout AF patients had significant dilation of all thefour PVs and LA compared wth patients without HF. In group II, the diameters ofostia PVs and LA were significantly enlarged than those in group I . Thediameters of all the four PVs and LA were found to be significantly increasedfrom NYHAII to NYHA IV in group I .CONCLUSIONS Significant dilation of the four PVs ostia with simultaneousLA enlargement was demonstrated in HF patients. The anatomic and geometricchanges in PVs and LA may participate in initiation and perpetuation of AF inpatients with HF.PART II AND mTITLE Effect of Heart Failure on the Tissue Structure of Myocardial Sleeves in Canine Pulmonary Veins.OBJECTIVE To investigate the effect of HF on the tissue structure of PVs in canine.METHODS Sixteen mongrel dogs were divided into congestive heart failure (HF) group (n=8) and normal control group (n=8) randomly. In the HF group, right ventricular pacing was performed with a rate of 240 bpm for about 4 weeks to establish HF model. We observed the arrangement of myocardial fibres, the level of interstinal fibrosis and the composition of type I and III collagens in the pulmonary vein sleeves using hematoxylin-eosin and sirius red staining. We also studied the quantities and distribution of Cx43 and ultrastructure of the pulmonary vein sleeves by immunohistochemistry and electron microscopy. RESULTS Four weeks later, stable HF was induced in 8 dogs in right ventricular pacing group. We observed more complex fiber orientations and increased interstitial fibrosis within the PV sleeves in HF group compared with control group(5.3+1.0% vs 2.1±0.7%, P<0.01). The quantities of type III collagen in HF group were significantly higher than those in normal control group(4.6±1.0% vs 1.6±0.7%, F<0.01 ). There was no difference in quantities of type I collagen between two groups(0.6±0.2% vs 0.6+0.3%, P>0.05). The ratio of type Ill/type I collagen was higher in HF group than control group(7.9±3.2 vs 3.0±1.9, F<0.01). The expression of Cx43 in pulmonary vein sleeves was increased in HF group compared with control group (3.3±0.6% vs 2.8±0.7%, P < 0.05). In addition, Cx43 distribution of the lateral membrane of the pulmonary vein sleeves myocytes increased in HF group compared with control group. The changes of ultrastructure from pulmonary vein sleeves tissue in HF dogs compared with Control dogs were mainly focus on enlarged mitochondria, disorganized cristae, decreased glycogen granule, and remodeling of intercellular intercalated disks.CONCLUSIONS HF can result in significant histological structural remodeling of PVs in canine, including derangement of myocardial fibers, amounts and composition changes of collagens, distribution and expression changes of gap junction proteins and structural abnormalities of mitochondria. In short, Structural remodeling of PVs in HF canine may supply a substrate for the initiation and maintenance of AF.