The Effect of Atrial Septal Defect Closure on Cardiac Volumetric Changes in Adults, Transcatheter Versus Surgical Closure, a Pilot Cardiac Magnetic Resonance Study

Background:Closure of an atrial septal defect(ASD)reduces right-side heart volumes by abolishing shunting with simultaneous improvement of the left ventricle(LV)filling and functions due to ventricular interdependence,thereby improving symptoms.Furthermore,studies conducted on atrial volume changes after ASD closure are limited.Cardiac magnetic resonance(CMR)is considered as the gold standard method for measuring cardiac volume and mass.Objective:We aimed to study the effect of transcatheter and surgical closure of secundum ASD on cardiac volumes and systolic functions as well as the fate of tricuspid regurgitation(TR),using CMR analysis.Methods:We prospectively enrolled 30 adult patients with isolated secundum ASD who were referred to ASD closure.CMR evaluation of cardiac chambers indexed volumes,systolic function,myocardial mass index,and tricuspid regurgitant fraction were done at before and 6 months after closure.Results:RV volumes decreased in both groups when compared to baseline(p-value 0.001),the device group had more reduction in volumes and more improvement in RV function after closure(p-value 0.001)when compared to the surgical arm.The changes in the RV mass index were insignificant between both groups(p-value 0.31).Functional TR improved to the same extent in both groups.Left ventricular end diastolic volume index(LVEDVI)and LV mass index increased sig-nificantly in both groups when compared to baseline in both groups but with no difference between groups p-value 0.01),left ventricular end systolic volume index(LVESVI)changes were insignificant.LV systolic function improved in patients who underwent device closure only(63.53±3.85 vs.67.13±4.34,p-value 0.01).There was a significant reduction in right atrial(RA)volumes and an insignificant decrease in left atrial(LA)volumes,with no difference between groups.Conclusion:Transcatheter and surgical secundum ASD closure resulted in volumetric changes in some cardiac chambers with better improvement in bi-ventricular systolic function in the transcatheter arm and no difference in the TR reduction between the two groups at 6 months follow-up by CMR.

Cardiac functional and ultrastructural changes in early diabetic cardiomyopathy rabbits

Objectives It is not fully clarified how diabetes mellitus induced cardiac dysfunction and myocardial ultrastructural changes in the early state.In the present study,we provided an integrated approach to investigate early changes in myocardial function of diabetic rabbits and assessed the structural alteration.Methods and Results Diabetes was induced by alloxan injection.After 30 days,echocardio- graphy and left ventricular cannulation were performed in dia- betic(D,n=8) and control rabbits(C,n= 10).After catheterization, animals were killed for histological studies.Hema-toxylin -eosin and Masson’s Trichrome staining of the heart were analyzed.The ultrastructure of left ventricle was also examined with electron microscopy.Echocardiography revealed that early diabetic cardiomyopathy had impaired LV diastolic function expressed by diminished E-waves,increased Awaves, E/A ratio reversion and increased E-wave deceleration time(EDT).Concurrently,LV end-diastolic pressure(LVEDP) and diastolic time constant(T) were increased,minimum dP/ dt(LV-dp/dt)was reduced,obtained through cardiac catheterization.There were no significant differences in LV ejection fraction(EF),LV peak systolic pressure(LVSP), or maximum dP/dt(LV + dp/dt).Qualitative light microscopy revealed no histologic changes in myocardium from diabetic rabbits.The most evident ultrastructural change was spotted myofibrillar damage,while interstitial fibrosis was slight.Conclusions These results suggest that early diabetic cardiomyopathy in animal model is characterized by left ventricular diastolic dysfunction,both impaired active relaxation and increased passive chamber stiffness.Whereas,left ventricular systolic function can remain normal.It might partly contribute to myofibrillar damage,but not myocardial fibrosis.

CARDIAC FUNCTION AND HISTOLOGICAL CHANGES AFTER NON-DYNAMIC CARDIOMYOPLASTY AND PRELIMINARY STUDY OF DYNAMIC CARDIOMYOPLASTY

By means of histological method and ultrasound cardiographic (UCG) examination, the left-right ratio of transectional area of muscle fiber of latissimus dorsi muscle (LDM) after non-dynamic cardiomyoplasty was 77.4% ?11.7% in GroupⅠ (3 weeks after operation), and 78.4+ 11.6% in Group Ⅱ (3 months after operation). There were muscular atrophy and hyperplasia of LDM, but the basical structure was retained. The ejection fraction (EF) decreased significantly after operation (P<0.05), but the difference between two groups was non?significant. Also, dynamic cardiomyoplasty was performed on a sheep. UCG showed the increased cardiac systolic function after operation. ATPase, succinodehydrogenase (SDH) and PAS examination implied the strengthening of fatigue-esistant ability in skeletal muscles after long-term electrical stimulation. So cardiomyoplasty is suggested to be a supplementary measure in treating end-stage heart failure.