Daniela Lax

Mild dehydration induces echocardiographic signs of mitral valve prolapse in healthy females with prior normal cardiac findings.

This study was designed to investigate the hypothesis that mitral valve prolapse (MVP) can be induced after diuresis in women without the abnormality who have characteristic body habitus. Fifteen tall, slim, healthy female volunteers with a normal cardiac findings, echocardiogram, and history were investigated after mild diuresis with furosemide and after placebo. All subjects lost weight after furosemide and placebo administration; but mean weight loss was significantly greater after furosemide administration than after placebo administration. Echocardiography showed MVP in none of the 15 patients before treatment, in seven after administration of placebo, and in seven after administration of furosemide. Coaptation point prolapsed superior to the anulus in seven subjects with echocardiographically determined MVP. Left ventricular end-diastolic dimensions decreased significantly after placebo or furosemide administration in subjects in whom MVP developed compared with the measurement in those in whom MVP did not develop. Murmurs characteristic of MVP disappeared in all four rehydrated subjects and echocardiographic changes resolved in two of the five rehydrated subjects. Thus echocardiographically determined MVP can be induced by mild dehydration in women with phenotypic body habitus of MVP; changes may resolve with rehydration. Results suggest an explanation for variable physical examination findings in persons with MVP.

Comparison of accuracy of diagnosis of congenital heart disease by history and physical examination versus echocardiography

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Left ventricular assist device support as a bridge to recovery in young children.

OBJECTIVE Left ventricular assist device (LVAD) experience and follow-up data in children are limited. We report the deployment and successful weaning from LVAD in young children with severe heart failure (HF). DESIGN From 2004--2009, 13 children suffering from HF were placed on LVAD. All presented with a dilated left ventricle (LV) with severely reduced contractility, secondary to myocarditis, atrial arrhythmia or idiopathic HF. This study reports their outcomes and longitudinal follow-up. RESULTS Of 13 young children with HF (ages 1 month--6 years; mean 19.2 months) placed on LVAD: eight weaned to recovery and successful hospital discharge, one was transplanted and four died. Echo follow-up in the weaned patients (mean age 22.1 months) revealed significant improvements from pre-LVAD measurements: LV end-diastolic dimension (LVED) mean z-score decreased from +4.8 to +0.95 (P < .001); fractional shortening (FS %) improved from a mean of 9.3% to 33% (P < .001); and the degree of mitral regurgitation (MR) significantly improved (P < .05). Time to LVAD deployment from HF diagnosis was more likely to be less than 30 days in the successfully weaned patients (100%) than patients who died or were transplanted (20%); P = .007. CONCLUSIONS LVAD support can be utilized as a bridge to recovery in young children with HF. Following LVAD weaning, children sustain improvements in LV size, function and degree of MR. LVAD deployment less than 30 days from HF diagnosis improves the likelihood of successful weaning and illustrates that children with acute etiologies of HF are more likely to achieve recovery.

Gender differences in dehydration-induced mitral valve prolapse

Mitral valve prolapse (MVP) is a common cardiac valve abnormality that affects women more frequently than men. We have previously shown that mild dehydration induces echocardiographic signs of MVP in approximately 50% of healthy asthenic women with previously normal cardiac findings. The present study was designed to investigate whether dehydration can induce MVP in normal men. Ten healthy male volunteers with a mean body mass index of 24.2 kg/m2, unremarkable history, and normal cardiac findings and echocardiogram were examined after mild diuresis with 20 mg furosemide. Significant decrease in weight, left ventricular end-diastolic dimension, and cardiac output were detected in all subjects after furosemide administration. In 1 (10%) of the 10 subjects echocardiographic MVP developed after furosemide administration. All furosemide-induced changes resolved with hydration. These results demonstrate that dehydration-induced MVP in men without characteristic body habitus of MVP occurs with substantially lower frequency than previously documented in women with the characteristic body habitus of MVP. This study suggests the importance of gender and body habitus in dehydration-induced MVP.

Remote Diagnosis of Congenital Heart Disease in Southern Arizona: Comparison Between Tele-echocardiography and Videotapes

OBJECTIVE We report our experience with tele-echocardiography and echocardiograms recorded digitally or on videotape (recorded-echos) at The University of Arizona from August 2006 to December 2010 and compare their quality and diagnostic accuracy. MATERIALS AND METHODS Tele-echocardiograms (tele-echos) were transmitted from the Yuma Regional Medical Center to The University of Arizona via a T-1 and aT-3 line at a bandwidth of 768 kilobits per second. Recorded-echos were shipped for interpretation to The University of Arizona by overnight mail. Diagnostic accuracy was assessed by comparing tele- and recorded-echos with electrocardiograms performed by a pediatric cardiologist (PedsCard-echos). RESULTS Three hundred forty-six tele-echos in 260 patients and 455 recorded-echos in 406 patients were performed (median age, 6 and 8 days, respectively). Indications included possible congenital heart disease (CHD), patent ductus arteriosus (PDA), and persistent pulmonary hypertension of the newborn. Diagnostic categories included complex CHD, non-critical disease, PDA, and other. PedsCard-echos were available for 27% of the tele-echo and 30% of the recorded-echo patients. Comparisons between tele- and PedsCard-echo yielded no discrepancies in 12 (23%), expected resolution of condition in 26 (49%), and minor in 14 (26%). One (2%) major discrepancy was detected. Comparisons between recorded- and PedsCard-echo showed no discrepancies in 28 (40%), expected resolution of condition in 14 (20%), and minor discrepancies in 28 (40%) patients. No significant difference with respect to discrepancies was detected between tele- and recorded-echos. There was significant (p<0.01) improvement in tele- and recorded-echo study quality by 2010. CONCLUSIONS (1) Tele-echocardiography can be performed successfully with excellent accuracy. (2) The quality of tele- and recorded-echo studies improved toward the end of the analysis period. (3) Although initially tele-echo studies were more accurate than recorded-echo studies, there was no difference between these two types of studies by the fourth year of the study. (4) Both tele- and recorded-echos were indispensible in the remote diagnosis of CHD.

Generation of furazolidone radical anion and its inhibition by glutathione

Furazolidone is a nitrofuran drug which causes dilated cardiomyopathy in turkeys and serves as an important model of human dilated cardiomyopathy. Although extensively investigated, the chemical mechanism by which furazolidone produces injury remains unknown. In this work we used electron paramagnetic resonance (EPR) spectroscopy to show that furazolidone was reduced to its corresponding nitro anion radical by ascorbate and hypoxanthine. Glutathione prevented the generation of this anion radical. These results document directly, with EPR spectroscopy, the presence of furazolidone anion radical during biochemical reduction and suggest a protective role of glutathione in furazolidone-induced injury. These data enhance our understanding of furazolidone metabolism and may be useful in defining its role in furazolidone-induced dilated cardiomyopathy.

Are All Ventricular Septal Defects Created Equal

The authors report the occurrence of infective endocarditis in a 32-year-old man with a ventricular septal defect and a left ventricular-to-right-atrial shunt who adhered to the revised 2007 American Heart Association guidelines for infective endocarditis. The patient had received antibiotic prophylaxis prior to multiple previous dental procedures. At a recent dental evaluation for fillings, he was informed that he no longer needed prophylaxis. Fatigue and fevers developed 1 week later, and he was treated with an oral course of ciprofloxacin. The symptoms recurred, and blood cultures grew Streptococcus viridans. A 7-mm vegetative mass was seen on the septal leaflet of the tricuspid valve during transesophageal echocardiography. This report raises the concern that patients with ventricular septal defects and left ventricular-to-right-atrial shunts are at higher risk for endocarditis and may require antibiotic prophylaxis.

Look before you close: atrial septal defect with undiagnosed partial anomalous pulmonary venous return.

The growing and continued success of percutaneous closure of atrial defects is related to its high benefit‐to‐risk ratio in appropriately selected patients. The following case illustrates a previously undocumented danger, namely, the potential for incomplete correction. A thorough transesophageal examination performed at the time of the planned atrial defect closure suggested the presence of a partial anomalous pulmonary vein insertion, which was then appropriately documented and the incomplete closure was averted.

Anisodamine increases blood flow to the retina-choroid and protects retinal and pancreatic cells against lipid peroxidation☆

This study investigated the effect of anisodamine (2 and 5 mg/kg i.v.) on ocular and systemic blood flow distribution in awake lambs using the radioactive microsphere technique. In separate in vitro studies, the effects of anisodamine (at final concentrations of 0.01 to 2.5 mg/ml) were determined on arachidonic acid, alloxan and ultraviolet radiation-induced lipid peroxidation of isolated retinal cells from rabbits and on alloxan-induced lipid peroxidation of hamster pancreatic islet beta cells. Malondialdehyde production was used as an index of lipid peroxidation and measured by the thiobarbituric acid method. Anisodamine preferentially increased blood flow and oxygen delivery to the retina-choroid and iris-ciliary body of the eye by 50-100%. Anisodamine significantly attenuated lipid peroxidation in retinal cells induced by ultraviolet radiation, alloxan and arachidonic acid by 17-50% and protected pancreatic beta cells against alloxan-induced lipid peroxidation. These properties may, in part, account for the beneficial effect of anisodamine in certain patients with diabetes.

Effects of hydration on mitral valve prolapse

We investigated the effect of hydration on mitral valve prolapse (MVP). Ten subjects with documented diagnosis of MVP were studied before and after oral hydration with 1 L of fluid. Increased weight and cardiac output were present after hydration. Results showed that all 10 subjects with diagnosis of MVP before hydration continued to have MVP after hydration; however, subtle changes were detected, especially on auscultation. Seven of 9 subjects (with cardiac examination recorded before and after hydration) had auscultatory findings of MVP before hydration. No detectable auscultatory change after hydration was present in one subject; in six subjects a loss of either a click or a murmur was detected after hydration. All subjects had echocardiographically detected MVP before hydration; evidence of MVP on two-dimensional or M-mode examination persisted after hydration in all 10 subjects. Minor changes in the echocardiographic examination (M-mode n = 2, Doppler n = 1) were detected in three subjects. Thus we found that hydration of subjects with MVP did not alter the overall diagnosis; however, changes occurred, especially on auscultation. This suggests that alterations in hydration may affect auscultatory expression of MVP and could explain, in part, the variable auscultatory findings in patients with MVP.