Extended trans-septal approach for mitral valve surgery: Our early experience

Background Extended trans septal (ETS) approach for mitral valve surgery often divides the artery to the Sino-Atrial node. The clinical implication of this is contentious. We analyzed our early results with ETS approach. Methods Between June 1998 and September 2003 eleven patients underwent mitral valve surgery by ETS approach. Six were females. Age ranged from 19 years to 67 years (median 40 years). Six underwent mitral valve replacement (MVR). Four underwent aortic and mitral (double) valve replacement (DVR). One had mitral valve repair. Three had additional procedures (tricuspid valve repair=1, Coronary artery bypass=1, Aorto bifemoral graft=1). Cardiopulmonary bypass ranged from 64 minutes to 77 minutes (median 72 minutes) for MVR and 112 minutes to 178 minutes (median 140 minutes) for DVR. Aortic cross clamp times ranged from 39 minutes to 52 minutes (median 47 minutes) for MVR and 74 minutes to 120 minutes (median 95 minutes) for DVR. Results There was no mortality or morbidity attributed to the ETS approach. One early death in emergency DVR was due to heart failure. Three patients needed seqeuntial pacing in the immediate post-operative period. Nine out of ten survivors were back to their preoperative rhythms on hospital discharge (6 sinus rhythm; 3 atrial fibrillation). One patient with preoperative trifascicular block who underwent reoperation to fix a paravalvular mitral leak needed a permanent pacemaker (VVI). The follow-up ranged from 1 month to 64 months (median 6 months) and is 100% complete. There was no late death or new arrhythmia. Conclusions Extended trans septal approach is safe. It gives excellent exposure of the mitral valve. division of the sinus node artery is not deleterious in the short to intermediate term. Presented at the 50th Annual Meeting of IACTS. New Delhi, Feb. 2004.     

Molecular diagnosis of Beckwith-Wiedemann syndrome using quantitative methylation-sensitive polymerase chain reaction.

PURPOSE: Beckwith-Wiedemann Syndrome is caused by defects in imprinted gene expression at 11p15. Currently, quantitative Southern analysis using DNA methylation-sensitive restriction enzymes is used in molecular diagnosis of this syndrome. METHODS: We describe a rapid and highly quantitative test for assessing DNA methylation at 11p15 using sodium bisulfite treatment of genomic DNA coupled with quantitative TaqMan methylation-sensitive polymerase chain reaction. RESULTS: TaqMan MSP can assess DNA methylation at both differentially methylated region (DMR)1 and DMR2 at 11p15. In addition, by using TaqMan MSP we were able to determine the parent of origin of a duplication of 11p15 by quantification of both DMR1 and DMR2 DNA methylation. CONCLUSION: TaqMan MSP method is a robust and rapid method for detecting changes in DNA methylation that compares favorably to the current standard of Southern blot for DNA methylation analysis. Assessment of DMR1 and DMR2 provides the most comprehensive assay for methylation defects in Beckwith Wiedemann Syndrome, accounting for more than 70% of the cases. The advantages of TaqMan MSP are that it requires less DNA and that it is rapid, less labor-intensive, and amenable to high-throughput analysis. Moreover, this approach can be modified to assess DNA methylation changes anywhere in the genome.     

Assessment of the accuracy of color Doppler flow mapping by digital image analysis

An in vitro steady flow experiment was performed in order to test the accuracy of velocity measurements obtained through color Doppler flow mapping (CDFM). Using the American Society of Echocardiography (ASE) flow phantom, low (maximum velocity = 60 cm/sec), medium (maximum velocity = 300 cm/sec) and high (maximum velocity = 600 cm/sec) speed accelerating flow fields, in which multiple aliases were visible, were imaged. A fully automatic computer algorithm was used to unwrap the aliases and to convert the CDFM to digital velocity. Packet size and wall filter frequency on the ultrasound machine were varied and the measured velocity compared to the true velocity. The results show that the velocity obtained in this way from the CDFM is very accurate at the low and medium velocities, but for the high velocity the turbulence is too intense to obtain an accurate result. There was no marked difference between the data for different packet sizes or wall filter settings.     

Evidence that microdeletions in the alpha globin gene protect against the development of sickle cell glomerulopathy in humans

There is a large variability in the severity of the clinical manifestations of sickle cell anemia (SSA), including renal involvement. Haplotypes in the beta-globin gene cluster associated with the geographical origin of the sickle mutation, as well as microdeletions in the alpha-globin genes, could provide an epigenetic influence on the heterogeneous outcome in SSA. It has been determined that the cause of progressive renal insufficiency in SSA is a glomerulopathy, clinically detected by the presence of macroalbuminuria (albumin excretion rate >300 mg/g creatinine). To investigate the role of the alpha-globin gene microdeletion and beta-globin gene cluster haplotypes on the degree of glomerular involvement, 76 adult SSA patients (hemoglobin SS) were studied to determine the relationship between these genetic markers and the development of sickle cell glomerulopathy. Macroalbuminuria was present in 22 (29%) of 76 adult SSA patients. The coinheritance of microdeletions in one or two of the four alpha-globin genes (alpha-thalassemia) was associated with a lower prevalence of macroalbuminuria (13%) versus patients with intact alpha-globin genes (40%, P = 0.01). By contrast, there was no association between albuminuria and beta-globin gene haplotypes (Central African Republic [CAR] versus non-CAR haplotypes). Patients with alpha-globin gene microdeletions had lower mean corpuscular volumes and mean corpuscular hemoglobin concentration than patients with all four alpha genes (86+/-2 versus 99+/-3 fl, and 33.9+/-0.2 versus 34.9+/-0.2%, respectively, P<0.05). There were no such hematologic differences between CAR and non-CAR beta-globin haplotypes. There were no differences in duration of disease (age), hemoglobin levels, reticulocyte index, and lactate dehydrogenase levels between those with and without glomerulopathy, but the mean arterial pressure was higher (87+/-1 mm Hg) in patients with intact alpha gene locus versus those with microdeletions (80+/-2 mm Hg, P<0.05). It is concluded that the coinheritance of microdeletions in the alpha-globin gene locus in SSA patients confers "renoprotection" by mechanisms not related to the degree of anemia or the severity of hemolysis, but could be related to a reduced mean corpuscular volume or to a lower erythrocyte hemoglobin concentration.     

Enhancing the Reliability in the Noninvasive Measurement of the His Bundle Magnetic Field Using a Novel Signal Averaging Methodology

Background: Extraction of the weak electrical activity of the “His Bundle” (HB) by noninvasive methods has not been very successful in the past. The study reassesses the use of signal averaged magnetocardiography (SAMCG), overcoming some of the limitations in earlier studies including in the signal averaging methodology. Methods: SAMCG on healthy subjects (14 male and 1 female) were performed using R‐peak as the fiducial point in all cases and also using QRS‐onset as the fiducial point in select cases. Results: A conspicuous feature (H) with a magnitude up to 200 femto Tesla (fT) attributed to the HB activity was observed in the PR segment at several spatial positions on the thorax, with onset at 35–50 ms before the QRS‐onset (V) in 15 out of 18 trials constituting 83% of cases studied. The QRS‐onset as the fiducial point resolved the feature better compared to the conventionally used R‐peak, especially in trials exhibiting spread in heart rate (HR). This is attributed to the fluctuations in Q_onRD (the time interval between QRS‐onset and R‐peak) compared to the temporal stability of the H‐V duration. Conclusions: SAMCG reveals a well‐resolved H feature. The double hump morphology of the feature extended at least up to a frequency of 150 Hz. The importance of the choice of QRS‐onset as the fiducial point is unequivocally demonstrated, illustrated by measurements on subjects exhibiting considerable heart rate variability. The latter has a general validity and should be applicable to SAECG as well.     

Double Giant Lambl’s Excrescence of aortic valve causing posterior circulation stroke

Diagnostic evaluation of embolic neurologic events requires the consideration of cardiac causes. Lambl’s Excrescences (LE)are filiform fronds that occur at sites of valvular closure due to “wear and tear” (Lambl Wien Med Wschr 6:244–247, 1856). The complex form of LE is “giant Lambl’s Excrescences” which results from the adherence of multiple adjacent excrescences that grow large. We recently had young male adult who presented with features of posterior circulation stroke (basilar) and detected to have two separate giant Lambl’s Excrescences on the aortic valve and treated successfully.     

Effect of adenosine triphosphate on the postischemic left ventricular function of the immature myocardium.

In this study, the effect of exogenous adenosine triphosphate (ATP) on the immature myocardium was evaluated. Isolated working neonatal rabbit hearts were perfused aerobically for 15 min with Krebs-Henseleit buffer (KHB) at 37 degrees C, and then arrested with St. Thomas solution (STS) in group 1 and STS containing 500 mumol/L of ATP in group 2 at 4 degrees to 6 degrees C and maintained at 10 degrees to 14 degrees C for 60 min. Hearts were reperfused with KHB aerobically at 37 degrees C for 15 min. Each heart served as its own control before and after arrest. Systolic function was significantly depressed in group 1 compared with group 2. There was a significant decrease in the peak left ventricular (LV) systolic pressure in group 1 (preischemia mean [PIM] 54 mm Hg to postischemia mean [PoIM] 42 mm Hg, Student's t test p = 0.007) than in group 2 (PIM 66 to PoIM 62 mm Hg, p = 0.5). The LV pulse pressure decreased in group 1 (PIM 72 to PoIM 54 mm Hg, p = 0.02) but not in group 2 (PIM 84 to PoIM 86 mm Hg, p = 0.9) and the rate of rise of LV pressure (dP/dT) in group 2 improved (PIM 5718 to PoIM 6926 mm Hg, p = 0.4) compared with group 1 (PIM 7021 to PoIM 4125 mm Hg, p = 0.008). The PoIM LV flow (LVF) was greater in group 2 than group 1 (LVF group 1 = 2.7 ml/min, group 2 = 4.5 ml/min). Diastolic pressures were not significantly different in the two groups. Our findings suggest that the incorporation of ATP in STS has a significant effect in improving postischemic LV systolic function in neonatal rabbit hearts.