Reflecting Before, During, and After the Heat of the Moment: A Review of Four Approaches for Supporting Health Staff to Manage Stressful Events

Being a healthcare professional in both paediatric and adult hospitals will mean being exposed to human tragedies and stressful events involving conflict, misunderstanding, and moral distress. There are a number of different structured approaches to reflection and discussion designed to support healthcare professionals process and make sense of their feelings and experiences and to mitigate against direct and vicarious trauma. In this paper, we draw from our experience in a large children's hospital and more broadly from the literature to identify and analyse four established approaches to facilitated reflective discussions. Each of the four approaches seeks to acknowledge the stressful nature of health professional work and to support clinicians from all healthcare professions to develop sustainable skills so they continue to grow and thrive as health professionals. Each approach also has the potential to open up feelings of uncertainty, frustration, sorrow, anguish, and moral distress for participants. We argue, therefore, that in order to avoid unintentionally causing harm, a facilitator should have specific skills required to safely lead the discussion and be able to explain the nature, scope, safe application, and limits of each approach. With reference to a hypothetical but realistic clinical case scenario, we discuss the application and key features of each approach, including the goals, underpinning theory, and methods of facilitation.

Public attitudes towards novel reproductive technologies: a citizens' jury on mitochondrial donation

STUDY QUESTION

Does an informed group of citizens endorse the clinical use of mitochondrial donation in a country where this is not currently permitted?

SUMMARY ANSWER

After hearing balanced expert evidence and having opportunity for deliberation, a majority (11/14) of participants in a citizens’ jury believed that children should be able to be born using mitochondrial donation.

WHAT IS KNOWN ALREADY

Research suggests that patients, oocyte donors and health professionals support mitochondrial donation to prevent transmission of mitochondrial disease. Less is known about public acceptability of this novel reproductive technology, especially from evidence using deliberative methods.

STUDY DESIGN, SIZE, DURATION

This study comprised a citizens’ jury, an established method for determining the views of a well-informed group of community members. The jury had 14 participants, and ran over one and a half days in 2017.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Jurors were members of the public with no experience of mitochondrial disease. They heard and engaged with relevant evidence and were asked to answer the question: ‘Should Australia allow children to be born following mitochondrial donation?’

MAIN RESULTS AND THE ROLE OF CHANCE

Eleven jurors decided that Australia should allow children to be born following mitochondrial donation; 7 of whom added conditions such as the need to limit who can access the intervention. Three jurors decided that children should not (or not yet) be born using this intervention. All jurors were particularly interested in the reliability of evidence, licensing/regulatory mechanisms and the rights of children to access information about their oocyte donors.

LIMITATIONS, REASONS FOR CAUTION

Jurors’ views were well informed and reflected critical deliberation and discussion, but are not intended to be representative of the whole population.

WIDER IMPLICATIONS OF THE FINDINGS

When presented with high quality evidence, combined with opportunities to undertake structured deliberation of novel reproductive technologies, members of the public are able to engage in detailed discussions. This is the first study to use an established deliberative method to gauge public views towards mitochondrial donation.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by a University of Sydney Industry and Community Collaboration Seed Award (2017), which was awarded contingent on additional funding from the Mito Foundation. Additional funding was provided by the Mito Foundation. The Foundation was not involved in jury facilitation or deliberation, nor analysis of research data.

TRIAL REGISTRATION NUMBER

Not applicable.

P1777Concordance and discordance among the recommended echocardiographic parameters for the assessment of mitral regurgitation severity

Background

The EACVI and ACC/AHA guidelines recommend assessing several echocardiographic parameters when evaluating mitral regurgitant severity. In a given patient, these parameters can be discordant making the assessment of mitral regurgitation challenging.

Purpose

To assess the degree to which echocardiographic parameters of MR severity are concordant.

Methods

This analysis included 131 consecutive patients with primary mitral regurgitation enrolled in a prospective multicenter study. Nine parameters were included in this analysis (PISA –derived regurgitant volume, PISA-derived EROA, vena contracta, color Doppler jet/LA area, LA volume index, LVEDVI, peak E wave, pulmonary vein systolic flow reversal, and presence of flail leaflet). Each echocardiographic parameter was determined to represent severe or nonsevere mitral regurgitation according to the guidelines. A concordance score was calculated as: (the number of concordant parameters/9) * 100 so that a higher score reflects greater concordance. Each echocardiogram was graded as having mild, moderate, or severe mitral regurgitation using the guideline recommended integrated approach.

Results

The mean concordance score was 74±13% for the entire cohort. There were 4 (4%) patients with complete agreement of all parameters and 32 (25%) with agreement of 5 of the 9 parameters. There was greater discordance in patients with severe MR and eccentric jets but no difference between patients with prolapse or flail leaflets (Figure 1). Clinical predictors of discordance were vena contracta and the peak E wave.

Figure 1

Conclusion

In this series, there was imperfect concordance between the recommended echocardiographic parameters of MR severity in patients undergoing evaluation for mitral regurgitation. The discordance was worse with more severe mitral regurgitation and there was no ideal predictor of discordance. These findings highlight the challenges facing echocardiographers when assessing the severity of mitral regurgitation and underscore the importance of using the integrated approach recommended by professional societal guidelines.

Acknowledgement/Funding

None

What parents want from doctors in end-of-life decision-making for children

OBJECTIVE

End-of-life decision-making is difficult for everyone involved, as many studies have shown. Within this complexity, there has been little information on how parents see the role of doctors in end-of-life decision-making for children. This study aimed to examine parents' views and experiences of end-of-life decision-making.

DESIGN

A qualitative method with a semistructured interview design was used.

SETTING

Parent participants were living in the community.

PARTICIPANTS

Twenty-five bereaved parents.

MAIN OUTCOMES

Parents reported varying roles taken by doctors: being the provider of information without opinion; giving information and advice as to the decision that should be taken; and seemingly being the decision maker for the child. The majority of parents found their child's doctor enabled them to be the ultimate decision maker for their child, which was what they very clearly wanted to be, and consequently enabled them to exercise their parental autonomy. Parents found it problematic when doctors took over decision-making. A less frequently reported, yet significant role for doctors was to affirm decisions after they had been made by parents. Other important aspects of the doctor's role were to provide follow-up support and referral.

CONCLUSIONS

Understanding the role that doctors take in end-of-life decisions, and the subsequent impact of that role from the perspective of parents can form the basis of better informed clinical practice.

Genetic selection for deafness: the views of hearing children of deaf adults

The concept of selecting for a disability, and deafness in particular, has triggered a controversial and sometimes acrimonious debate between key stakeholders. Previous studies have concentrated on the views of the deaf and hard of hearing, health professionals and ethicists towards reproductive selection for deafness. This study, however, is the first of its kind examining the views of hearing children of deaf adults towards preimplantation genetic diagnosis and prenatal diagnosis to select for or against deafness. Hearing children of deaf adults (or CODAs, as they call themselves, and are widely known in the deaf community) straddle both the deaf and hearing worlds, and this dual perspective makes them ideally placed to add to the academic discourse concerning the use of genetic selection for or against deafness. The study incorporated two complementary stages, using initial, semistructured interviews with key informants (CODAs and health professionals) as a means to guide the subsequent development of an electronic survey, completed anonymously by 66 individuals. The participants shared many of the same views as deaf individuals in the D/deaf (or "culturally deaf") community. The similarities extended to their opinions regarding deafness not being a disability (45.5% believed deafness was a distinct culture rather than a disability), their ambivalence towards having hearing or deaf children (72.3% indicated no preference) and their general disapproval of the use of genetic technologies to select either for or against deafness (60% believed that reproductive technologies, when used to select for or against deafness, should not be available to the community).

Medical and ethical considerations in twin pregnancies discordant for serious cardiac disease

OBJECTIVE

Prenatal ultrasound has led to the early diagnosis of major anomalies. However, the ready availability of this technology has led to increasing challenges for physicians counseling affected parents, which is all the more difficult in a twin pregnancy with only one affected fetus. This paper reviews the medical and ethical considerations in twin pregnancies discordant for a serious cardiac condition.

STUDY DESIGN

Six recent twin pregnancies discordant for a serious cardiac condition and their outcomes are presented. Options considered in the management of the pregnancy were to continue or terminate the pregnancy, selectively terminate the affected twin or to decide whether to treat the affected twin once delivered. An approach to decision making in such situations has been formulated after critical analysis of the factors involved.

RESULTS

Four of the six pregnancies were monochorionic twins. Two sets of parents decided to terminate the pregnancy. In the four that continued, two opted for the affected twin to be appropriately managed once delivered. A further two considered selective termination but opted to continue the pregnancy because of the risk of premature labor and/or cerebral hypoxia following such intervention. They sought a commitment, however, that they be given the option whether to treat the affected twin following delivery. Eventually both elected to have their babies treated, one of whom died in the postoperative period.

DISCUSSION

Medical considerations included the risks of continuation of the pregnancy for the mother and her twins, the safety of termination (total or selective), and the risks to the unaffected fetus. Ethical issues revolved around concepts of autonomy, beneficence and justice from the standpoint of the family and the twins. The gestation and the viability of the twins played an important role in decision making and approaches, taking into account the local legal and other considerations.

CONCLUSION

Attention is drawn to the complexities of the issues involved in twin pregnancies complicated by a serious cardiac condition in one of the twins. Optimal counseling requires sound clinical knowledge about the medical risks to the mother and her twins, and a clear understanding of the key ethical considerations. Such an approach will assist parents in their very difficult decision making.

Human 2D (index) and 4D (ring) finger lengths and ratios: cross-sectional data on linear growth patterns, sexual dimorphism and lateral asymmetry from 4 to 60 years of age

Human 2D : 4D ratios (measures of the relative lengths of index and ring fingers) attract considerable research interest because they exhibit sexual dimorphism and are associated with various morphological, physiological and behavioural traits as well as sporting abilities and medical conditions. In an attempt to identify potential confounding factors in such studies, we have examined how relative and absolute digit lengths vary with gender and tested whether they are influenced by age, right-left asymmetry and hand preference. Participants between 4 and 60 years of age were recruited from local educational sites. Hand photocopies and calliper measurement were used to obtain digit lengths. We employed linear regression analysis to examine the growth trajectories of individual digits, analyses of variance to isolate main and interaction effects of age, gender and hand preference, and paired t-tests to identify lateral asymmetries. Both digits exhibited biphasic growth with an early growth phase followed by a stable length phase. Digits in females attained their maximum length about 2.2 years (dextral subjects) or 5.1 years (sinistral subjects) earlier than those in males. Sexual dimorphism in 2D : 4D ratios was apparent by 4 years of age and age changes in ratios depended on gender, side and hand preference. Relative and absolute lengths displayed age, gender, hand-preference and age x gender interaction effects. Lengths tended to be greater in females in younger subjects and greater in males in older subjects. Ratios tended to be greater in sinistral subjects. In dextral subjects, significant lateral asymmetries in 2D lengths were seen at all ages but asymmetries in males and 4D lengths seemed to be age-dependent. We conclude that age, lateral asymmetry and hand preference are potential confounding factors and that future study designs should take account of these as well as other known confounders such as ethnicity, birth order, menstrual cycle phase and sexual preference.

Human 2D (index) and 4D (ring) digit lengths: their variation and relationships during the menstrual cycle

It is known that there are sexually dimorphic differences in relative and absolute lengths of the index (2nd) and ring (4th) fingers and that the sizes of laterally-paired soft tissues (e.g. ears and fingers) show changes across the menstrual cycle. The aim of the present study was to determine whether cyclical changes in the digit lengths of the index and ring fingers also occur and, if so, to what extent these are related to changing patterns of circulating sex steroids. Digit lengths were assessed over two cycles in groups of right-handed females (19-21 years of age) who were divided on the basis of whether or not they were taking oral contraceptive pills (n = 13 and n = 6 respectively). Using callipers, finger lengths were measured on photocopy images of both hands taken at 4-day intervals for a total of 56 days. We tested the following null hypotheses: (1) digit length measurements do not exhibit fluctuations across the menstrual cycle; (2) there is no evidence of lateral asymmetry between measurements made on both hands; (3) the lengths of digits 2 and 4 do not differ in either hand. Null hypotheses were tested using Page's L trends test for related samples (cyclical fluctuations) and paired Student's t tests (left-right asymmetries and within-hand digital differences). In those not taking oral contraceptives, finger lengths and 2D:4D digit ratios fluctuated across the cycle with values tending to increase in the pre-ovulatory period and decline thereafter. Left-right asymmetries varied in a similar fashion with lengths generally being larger, and lateral asymmetries smaller, in the dominant hand. Although sample sizes were smaller, some of these patterns were retained but others were perturbed in those practising oral contraception. We conclude that finger lengths are cycle-dependent and that account should be taken of this, and of oral contraceptive usage, in future studies on female digit lengths and their ratios.

The contribution of GJB2 mutations to slight or mild hearing loss in Australian elementary school children

BACKGROUND

There is a lack of information on prevalence, cause and consequences of slight/mild bilateral sensorineural hearing loss (SNHL) in children. We report the first systematic genetic analysis of the GJB2 gene in a population-derived sample of children with slight/mild bilateral SNHL.

METHODS

Hearing tests were conducted in 6240 Australian elementary school children in Grades 1 and 5. 55 children (0.88%) were found to have a slight/mild sensorineural hearing loss. 48 children with slight/mild sensorineural hearing loss and a matched group of 90 children with normal hearing participated in a genetic study investigating mutations in the GJB2 gene, coding for connexin 26, and the presence of the del(GJB6-D13S1830) and del(GJB6-D13S1854) deletions in the GJB6 gene, coding for connexin 30.

RESULTS

Four of 48 children with slight/mild sensorineural hearing loss were homozygous for the GJB2 V37I change. The four children with homozygous V37I mutations were all of Asian background and analysis of SNPs in or near the GJB2 gene suggests that the V37I mutation arose from a single mutational event in the Asian population.

DISCUSSION

Based on the prevalence of carriers of this change we conclude that V37I can be a causative mutation that is often associated with slight/mild sensorineural hearing loss. No other children in the slight/mild hearing loss group had a hearing loss related to a GJB2 mutation. One child with normal hearing was homozygous for the R127H change and we conclude that this change does not cause hearing loss. Two children of Asian background were carriers of the V37I mutation. Our data indicate that slight/mild sensorineural hearing loss due to the GJB2 V37I mutation is common in people of Asian background.

Enhancing the ethical conduct of genetic research: investigating views of parents on including their healthy children in a study on mild hearing loss

Clinical genetic research is often regarded as more ethically problematic than other forms of research, and in some countries is subject to specific regulation, requiring researchers to follow specialised guidelines. In this paper, an approach to enhancing the ethical conduct of genetic research is proposed, which is believed to be more effective than simply attempting to follow general guidelines. The potential concerns, likely areas of misunderstanding and negative reactions of the participant group are systematically investigated before starting a study on genetics. This would constitute, in effect, an ethical pilot study, similar to a feasibility pilot study to test equipment, procedures and logistics. The findings of the ethical pilot study would be used to help in designing ethically important aspects of research protocol, such as recruitment procedures, written and other information for potential participants, informed consent processes and reporting of results including ambiguous or uncertain results.

Confidentiality

Issues of confidentiality are complicated by the relationships we have to patients and others who have valid interests in the confidential information. There are no straightforward answers to problems which involve complex relationships and sensitive information. The best we can do is to think thoroughly and carefully about the issues in each case, and use our knowledge of the people involved to reach a decision. Doctors faced with difficult decisions of this kind should be assured that everyone finds them difficult. Sharing the burden with experienced colleagues can be helpful.

Reversibility and pathohistological basis of left ventricular remodeling in hibernating myocardium

The phenomenon of left ventricular (LV) remodeling with dilatation, wall thinning, and increased muscle mass has previously been reported in pigs with 7-day myocardial hibernation. This study investigated cellular and extracellular basis and reversibility of the structural LV remodeling with hibernating myocardium. Five groups of pigs were included: Group A: 7-day myocardial hibernation with a fixed coronary stenosis; Group B: 7-day hibernation with subsequent 3-week reperfusion by release of the stenosis; Group C: control group with sham operation; Group D: 24-hour myocardial hibernation to define structural mechanism of initial wall thinning in the hibernating region without confounding factors of cell loss or hypertrophy, Group E: 4-week myocardial hibernation to exclude the possibility of spontaneous regression of LV remodeling with hibernation. LAD flow decreased by 38+/-12% (p<0.01) with a significant decrease in systolic wall thickening at 7 days of hibernation with severe coronary stenosis (Group A). End-diastolic wall thickness decreased by 19% (p<0.01) accompanied by a decrease in myocyte number across the wall (44%) and in myocyte density (24%), a significant increase in myocyte width (17%), a mild increase in interstitial tissues in hibernating region, and significant increases in LV diastolic volume and in LV mass at 7 days. After reperfusion (Group B), LV volume decreased, LV ejection fraction improved, and myocyte hypertrophy regressed with a decreased LV mass index without a significant change in interstitial tissue. LV remodeling progressed with further increases in LV volume, mass, and interstitial fibrosis in 4-week hibernation. In pigs undergoing 24 hours of myocardial hibernation (Group D), end-diastolic LV wall thickness decreased significantly in the hibernating region with a proportional decrease in the transmural myocyte number but without changes in myocyte width, myocyte density, or interstitial tissues. Therefore, progressive gross LV remodeling associated with hibernating myocardium is accompanied by increasing myocyte hypertrophy and interstitial fibrosis. In hibernating myocardial region, wall thinning is proportional to a decreased myocyte number across the LV wall, indicating slippage of myocytes as a preponderant mechanism for the wall thinning. Myocyte hypertrophy develops within 7 days in hibernating myocardium, causing an increase in LV mass. These changes are partially reversible after reperfusion.

Impact of delayed reperfusion of myocardial hibernation on myocardial ultrastructure and function and their recoveries after reperfusion in a pig model of myocardial hibernation

This study examined the effect of delayed reperfusion of myocardial hibernation from 24 hours to 7 days on myocardial ultrastructural and functional changes and their recoveries after reperfusion.

BACKGROUND

We have previously shown in pigs that after reperfusion the functional and structural alterations in short-term myocardial hibernation which was reperfused in 24 hours can recover in 7 days. The effect of delayed reperfusion of hibernating myocardium on the extent and severity of cellular and extracellular structural changes of hibernating myocardium, and their recoveries after reperfusion is not known.

METHODS AND RESULTS

A severe LAD stenosis was created in 27 pigs, reducing resting flow by 30-40% immediately after placement of the stenosis and producing acute ischemia as evidenced by regional lactate production, a decrease in regional coronary venous pH, reduced regional wall thickening (from 38.5 +/- 5.1% to 10.4 +/- 8.0%) and a 33% reduction of regional oxygen consumption. The stenosis was maintained either for 24 hours in 9 pigs (group 1) with LAD flow of 0.65 +/- 0.13 ml/min/g (38% reduction), or for 7 days in 17 pigs (group 2) with LAD flow of 0.67 +/- 0.14 ml/min/g (36% reduction). There were no differences (p = NS) in the reduction of wall thickening, rate-pressure product, lactate production, or regional oxygen consumption between group 1 and group 2. Quantitative morphometric evaluation of the ultrastructure on electromicrographs revealed a greater decrease in sarcomere volume and a higher incidence of myocytes with reduced sarcomere volume in 7-day than in 24-hour hibernating regions (53 +/- 19% versus 33 +/- 14%, p < 0.05). Patchy myocardial necrosis with replacement fibrosis was common, but 6 of the 18 pigs had no myocardial necrosis or replacement fibrosis in the 7-day hibernating group, and 4 of 9 pigs had no patchy myocyte necrosis in the 24 hour hibernating group. In 6 pigs in group 1 in which the stenosis was then released and hibernating myocardium reperfused in 24 hours, regional wall thickening recovered to 30 +/- 6% (p = NS compared to baseline) after one week of reperfusion. In 12 pigs in group 2 in which the stenosis was released and hibernating myocardium reperfused in 7 days, regional wall thickening recovered slowly, from 10.1 +/- 7.2% to 18.1 +/- 8.3% at one week (n = 5) and to 28.0 +/- 3.6% at 3-4 weeks of reperfusion (n = 7, p < 0.05 compared to baseline). Similarly, the sarcomere volume or myofilament recovered significantly (p < 0.01) and was not different compared to the normal region (p = NS) in the 24-hour hibernating region of group 1, but the recovery was much slower and was incomplete at 4 weeks (p < 0.01) compared to baseline in the 7-day hibernating region of group 2. Recovery of regional wall thickening correlated with ultrstructural recovery (p < 0.01). By multivariate stepwise regression analysis, the degree of LAD flow reduction, the extent of fibrosis, and myofilament loss were independent predictors of the extent of functional recovery.

CONCLUSIONS

In a porcine model of myocardial hibernation with myocardial hypoperfusion, systolic dysfunction, and metabolic adaptations, a longer period of myocardial hibernation with delayed reperfusion was associated with more severe abnormalities of myocytes. an increasing interstitial fibrosis, and more protracted myofibrillar and functional recoveries after reperfusion. The extent of functional recovery is related to the degree of coronary flow reduction, the severity of the ultrastructural changes, and the extent of interstitial fibrosis.

Prenatal diagnosis and discrimination against the disabled

Two versions of the argument that prenatal diagnosis discriminates against the disabled are distinguished and analysed. Both are shown to be inadequate, but some valid concerns about the social effects of prenatal diagnosis are highlighted.

Use of an intravenous contrast agent (Optison) to enhance echocardiography: efficacy and cost implications. Optison Multicenter Study Group

OBJECTIVE

To compare the overall diagnostic costs associated with non-contrast and contrast echocardiography.

STUDY DESIGN

Phase III clinical trial.

PATIENTS AND METHODS

In a secondary analysis of data from a phase III clinical trial of the intravenous contrast agent Optison, we compared the costs associated with obtaining a diagnosis in 203 patients who underwent non-contrast and contrast echocardiography. Costs for the initial test and any follow-up tests were derived from adjusted Medicare charges and a transition-1 microcost accounting system.

RESULTS

Diagnostic yield from echocardiograms was 87% with the use of Optison (3 mL) and 49% when no contrast agent was used (P < 0.001). Because technically inadequate echocardiograms were more common in the non-contrast group, follow-up testing was recommended for 42% of patients in this group compared with 12% of those who had undergone a contrast-enhanced echocardiogram (P < 0.001). Although use of Optison increased the initial diagnostic cost by $125, overall costs were 17% lower when Optison was used (P < 0.0001). Use of Optison also resulted in a 17% to 70% decrease in confirmatory transesophageal echocardiography, catheterization, and nuclear studies. Optison improved diagnostic accuracy by 2.7-fold in patients with an initial non-diagnostic echocardiogram, resulting in a substantial cost savings of $269 per patient.

Toxic methemoglobinemia: a rare but serious complication of transesophageal echocardiography

Cyanosis occurring during a transesophageal echocardiogram (TEE) is usually related to the respiratory depressant effect of the administered sedative. However, acute toxic methemoglobinemia related to topical benzocaine is a rare and not well recognized but potentially life threatening cause of cyanosis during or after TEE. A case of this condition is presented and the literature on its frequency, diagnosis and management is briefly reviewed.

The 'more-abortions' objection to fetal tissue transplantation

One common objection to fetal tissue transplantation (FTT) is that, if it were to become a standard form of treatment, it would encourage or entrench the practice of abortion. This claim is at least factually plausible, although it cannot be definitively established. However, even if true, it does not constitute a compelling ethical argument against FTT. The harm allegedly brought about by FTT, when assessed by widely accepted non-consequentialist criteria, has limited moral significance. Even if FTT would cause more abortions to be performed, and abortion is taken to be a serious moral wrong, this is not sufficient in itself to make FTT wrong.

Nitroglycerin enhances the ability of dobutamine stress echocardiography to detect hibernating myocardium

BACKGROUND

A biphasic response of wall thickening with initial improvement and subsequent deterioration during dobutamine stress echocardiography (DSE) has been increasingly used for detection of hibernating myocardium. However, the improvement of wall thickening at low-dose DSE may be limited in hibernating myocardium by severe hypoperfusion. Nitroglycerin (NTG) improves myocardial perfusion, reduces oxygen demand, and may enhance low-dose dobutamine to improve wall thickening.

METHODS AND RESULTS

A pig model of myocardial hibernation of 24 hours to 7 days was created through severe left anterior descending coronary artery stenosis with coronary flow reductions of approximately 40%, producing severe regional left ventricular dysfunction but no infarction in seven pigs. Myocardial infarction was produced in five pigs with occlusion of the artery. DSE was performed with incremental doses with and without an NTG infusion of 50 to 100 microg/min. In the hibernating group, NTG alone improved wall thickening in the hibernating region modestly from 11.4+/-7.2% at baseline to 19.1+/-7.0%. The improvement was associated with increased regional coronary flow from 0.46+/-0.12 to 0.55+/-0.13 mL x beat(-1) x 100 g myocardium(-1) (P<.05). There was an additive effect of NTG to low-dose (2.5 to 5 microg x kg(-1) x min(-1)) dobutamine on wall thickening in the hibernating region. The improvement of wall thickening of hibernating myocardium with NTG and dobutamine, from 23.7+/-11.1% to 31.1+/-8.9% (P<.001), was associated with an increase in regional coronary flow (P<.01). NTG did not prevent high doses of dobutamine from inducing deterioration of wall thickening in hibernating myocardium. In the infarcted group, no improvement in wall thickening was observed in infarcted regions during NTG infusion, dobutamine infusion, or the combination.

CONCLUSIONS

NTG enhances the improvement of wall thickening at low-dose dobutamine and does not prevent high-dose dobutamine from inducing ischemia in hibernating myocardium. Thus, NTG augments the biphasic response of wall thickening and improves the accuracy of DSE for detecting viable myocardium.

Lupus-related mitral valve disease: embolic coronary occlusion as a unique cause of myocardial infarction

Early diagnosis and greatly improved treatment have markedly altered the clinical evolution of systemic lupus erythematosus; the pattern of cardiac involvement in lupus has also changed. To illustrate this, a young woman who died from severe mitral valve disease, including a coronary embolus from verrucous endocarditis, is presented. Mitral valve involvement in lupus is no longer limited to the small benign lesions described by Libman and Sacks.

Effects of beta-blockade and atropine on ischemic responses in left ventricular regions subtending coronary stenosis during dobutamine stress echocardiography

OBJECTIVES

This study was designed to examine the effects of a beta-adrenergic blocking agent on the ischemic response to dobutamine stress and to determine the degree to which these effects can be abolished by the addition of atropine.

BACKGROUND

Whether beta-blockade affects the sensitivity of dobutamine stress echocardiography for the diagnosis of coronary artery disease has been controversial.

METHODS

In nine pigs, a left anterior descending coronary artery stenosis was created to reduce flow reserve (maximal/rest flow) to 1.1 to 1.9 without baseline regional wall motion abnormalities. This corresponded to a 50% to 90% diameter stenosis. Wall thickening was measured using epicardial echocardiography. Regional lactate production and coronary venous pH were monitored from an adjacent cardiac vein. A standard protocol of dobutamine stress echocardiography was first performed. After normalization of the ischemic abnormalities elicited with this infusion, esmolol was infused at 50 micrograms/kg body weight per min and the dobutamine test was repeated, with 1.0 mg of atropine added at the maximal dobutamine dose.

RESULTS

Without esmolol, dobutamine stress induced myocardial ischemia with a reduction in regional wall thickening and lactate production in all nine pigs. Multiple regression analysis revealed that coronary flow per heartbeat (p < 0.01) and lactate production (p < 0.05) independently correlated with regional wall thickening during dobutamine stress. The beta-blocker significantly reduced heart rate and regional oxygen consumption and altered the relation between coronary flow per heartbeat and regional wall thickening (p < 0.05) during dobutamine stress. Esmolol prevented dobutamine-induced ischemia (lactate production and wall motion abnormalities) in seven of nine pigs. The addition of atropine induced lactate production and a reduction in wall thickening in five of seven pigs in which ischemia had been prevented by beta-blockade. However, lactate production was higher and regional venous pH was lower with the baseline dobutamine infusion than with that performed after esmolol with atropine added at the maximal dobutamine dose (p < 0.05).

CONCLUSIONS

A correlation between regional wall thickening and coronary flow per heartbeat was demonstrated during baseline dobutamine stress. Beta-blockade shifted this relation so that dobutamine stress-induced myocardial ischemia was attenuated. The mechanisms by which beta-blockade prevents dobutamine-induced ischemia appeared to be mainly through decreases in heart rate and rate of rise in left ventricular pressure, improvement of regional coronary flow per heartbeat and attenuation of regional ischemic lactate production. Adding atropine in conventional doses enhanced the ability of dobutamine stress to induce myocardial ischemia but did not completely abolish the effects of beta-blockade on either the severity of dobutamine-induced wall thickening abnormalities or regional metabolic disturbances.

Incremental doses of dobutamine induce a biphasic response in dysfunctional left ventricular regions subtending coronary stenoses

BACKGROUND

Dobutamine stress echocardiography has been proposed as a diagnostic tool to identify viable myocardium. How regional wall thickening responds to dobutamine in the ischemic or short-term hibernating myocardium has not been adequately defined. We hypothesized that regional wall thickening would improve initially and subsequently deteriorate with incremental doses of dobutamine in viable myocardial regions supplied by a stenotic coronary artery. This study was undertaken to determine whether this biphasic pattern of regional function characterizes the response of ischemic or hibernating myocardium to dobutamine and to explore the factors and mechanisms that determine this response.

METHODS AND RESULTS

Twenty-six pigs in four groups were studied: a control group (n = 5) to assess the response of myocardium perfused by nonstenotic coronary artery to incremental doses of dobutamine, and three experimental groups with a left anterior descending coronary artery stenosis producing acute myocardial ischemia (n = 7), short-term myocardial hibernation for 90 minutes (n = 7), and short-term hibernation for 24 hours (n = 7) to determine the functional and metabolic response to dobutamine under these conditions. Regional coronary flow was reduced to 40% to 60% of baseline, with significant reductions of regional wall thickening as measured by two-dimensional echocardiography and sonomicrometers. An incremental dobutamine infusion from 2.5 to 25 micrograms.kg-1.min-1 increased wall thickening and coronary flow without lactate production in the control group. In the other three groups, during the incremental dobutamine infusion, regional wall thickening improved initially, from 11.4 +/- 7.5% to 19.8 +/- 11.4%, P < .01, at dobutamine doses of 2.5 to 10 (4.5 +/- 2.2) micrograms.min-1.kg-1 but deteriorated subsequently to 5.0 +/- 5.8% at the maximal dose of dobutamine of 12.6 +/- 4.1 micrograms.min-1.kg-1. The initial improvement of regional wall thickening was associated with a small increase in regional coronary flow (from 0.53 +/- 0.18 to 0.68 +/- 0.25 mL.min-1.g-1 myocardium, P < .05) and with regional lactate production. High doses of dobutamine did not further increase regional coronary flow but markedly increased lactate production and induced regional myocardial acidosis (pH 7.26 +/- 0.07). The biphasic pattern of response to dobutamine was observed in each of the three experimental groups. Both peak improvement and peak deterioration occurred earlier and at lower dobutamine dose levels in the group with acute ischemia compared with the group with short-term hibernation for 24 hours (P < .05).

CONCLUSIONS

A biphasic response of wall thickening to incremental dobutamine with initial improvement and subsequent deterioration is characteristic of ischemic or short-term hibernating myocardium. The initial low-dose dobutamine infusion improved wall thickening in the ischemic or hibernating myocardial region to a modest level. This initial modest improvement was transient and at the expense of metabolic deterioration of myocardial ischemia, so that at higher doses during prolonged dobutamine infusion, wall thickening deteriorated, lactate accumulated, and myocardial acidosis developed.

Biplane transesophageal color Doppler echocardiography for assessment of mitral valve area with mitral inflow jet widths

Biplane transesophageal color Doppler echocardiography can image the mitral valve orifice in two orthogonal views. If the maximal stenotic jet width through the mitral valve obtained with the vertical transducer represents the major axis, the stenotic jet width dissected by the horizontal transducer should be the minor axis of the mitral orifice. Thus the mitral valve area can be calculated assuming an oval shape of mitral orifice. Nineteen patients with mitral stenosis were investigated. Maximal mitral stenotic jet width (JW1) was searched on a vertical plane and the jet width from the orthogonal view (JW2) was obtained on a horizontal plane. Mitral valve areas from the color Doppler jet widths were calculated by pi.JW1/2.JW2/2 and compared with those derived from Gorlin's formula. Adequate quality of echocardiographic images could be obtained in all patients for transesophageal color Doppler jet width measurements or Doppler pressure half-time determinations and in 16 of 19 patients for transthoracic planimetery of the mitral orifice at the parasternal short axis. Mitral valve areas derived from biplane transesophageal color Doppler imaging (1.31 +/- 0.53 cm2) were not different from those calculated according to Gorlin's formula from the catheterization data (1.25 +/- 0.50 cm2), those determined by transthoracic echocardiographic planimetery (1.38 +/- 0.5 cm2), or those calculated from the Doppler pressure half-time method (1.32 +/- 0.41 cm2) (difference not significant by analysis of variance). There was a very strong correlation between transesophageal echocardiographic mitral valve areas and those derived from catheterization data (r = 0.94; standard error of the estimate = 0.13 cm2). A similar correlation was obtained for the planimetric echocardiographic method (r = 0.94; standard error of the estimate = 0.14 cm2). A slightly less strong correlation was found between mitral valve areas derived from the Doppler pressure half-time method and those derived from Gorlin's formula (r = 0.83; standard error of the estimate = 0.24 cm2). The pressure half-time method accurately predicted the mitral valve area in most (15/19) patients, but it significantly (> 0.4 cm2) overestimated mitral valve area in two patients with aortic regurgitation and underestimated (< 0.4 cm2) mitral valve area in two patients with left ventricular hypertrophy. Determination of mitral valve area by color Doppler biplane transesophageal echocardiography is an alternative for accurate estimation of mitral valve area and may be most useful in intraoperative monitoring during surgical or balloon mitral commissurotomy or in the case of inadequate imaging quality of transthoracic echocardiography.

Aortic regurgitation shortens Doppler pressure half-time in mitral stenosis: clinical evidence, in vitro simulation and theoretic analysis

Mitral valve areas determined by Doppler pressure half-time were compared with areas obtained by planimetry in two groups of patients with mitral stenosis: 24 patients without aortic regurgitation and 32 patients with more than grade 1 aortic regurgitation. The severity of aortic regurgitation was assessed by color flow mapping; 17 patients had grade 2, 10 had grade 3 and 5 had grade 4 aortic regurgitation. Regression equations for pressure half-time area versus planimetry mitral valve area were calculated separately for the aortic regurgitation (r = 0.88) and the nonaortic regurgitation group (r = 0.86); analysis of covariance revealed a significant (p less than 0.001) difference between the two groups leading to overestimation of planimetry area by the pressure half-time method in the aortic regurgitation group. The mitral valve areas in the group without regurgitation were best calculated with the expression 239/T1/2 (r = 0.77) as compared with a best fit of 195/T1/2 (r = 0.85) for the aortic regurgitation group. To elucidate the mechanisms affecting pressure half-time in aortic regurgitation, an in vitro model of mitral inflow in the presence of varying regurgitant volumes and different ventricular chamber compliances was used. Aortic regurgitation shortened directly measured pressure half-time proportional to the regurgitant fraction but an increase in left ventricular compliance could offset this effect. Finally, in a mathematic model of mitral inflow the competing effects of aortic regurgitation and chamber compliance could be confirmed. In conclusion, aortic regurgitation results clinically in a significant net shortening of pressure half-time leading to mitral valve area overestimation. However, the effect is moderate and individually unpredictable because of changes in chamber compliance.

Congenital aneurysms of the left atrium: recognition by cross-sectional echocardiography

The two-dimensional echocardiographic features of three patients with congenital aneurysms of the left atrium are described. The aneurysm arose from the left atrial appendage in two patients and from the posterior left atrial wall in one. The aneurysms were characterized by their origin from an otherwise normal left atrium, a well-defined neck, their position within the pericardial space, and distortion of the left ventricular free wall by the aneurysmal body. The differentiation of these structures from other abnormalities of the left atrium are also discussed. Two-dimensional echocardiography is a safe and reliable method for diagnosing congenital aneurysm of the left atrium, and such studies should be considered in any patient with an otherwise unexplained abnormality on the chest radiograph.