Comparing characteristics and clinical and echocardiographic outcomes in low-flow vs normal-flow severe aortic stenosis with preserved ejection fraction in an Asian population.

BACKGROUND/OBJECTIVES: In severe aortic stenosis (AS), deterioration of left ventricular ejection fraction (LVEF) to <50% is an AHA/ACC class I indication for valve replacement, regardless of symptoms. Controversy surrounds prognosis of low-flow AS compared to normal-flow, and no study has examined LVEF deterioration. We compared factors associated with LVEF deterioration (to <50%) and clinical outcomes. METHODS: Consecutive subjects with low-flow (stroke volume index <35 mL/m2 , n=56) and normal-flow (n=72) severe AS (aortic valve area <1 cm2 ) with preserved LVEF (>50%) and with paired echocardiography were studied. Univariate and multivariate analyses identified factors associated with LVEF deterioration. Clinical outcomes were determined on follow-up for more than 5 years. RESULTS: Significant LVEF deterioration (to <50%) was seen in 18% of low-flow (initial LVEF 63±8% to 32±9%) and 18% of normal-flow AS (61±7% to 31±12%). Independent factors in low-flow AS were hypertension (OR: 30.7, 95% CI: 2.0-467.6, P=.014) and higher end-systolic wall stress (OR: 1.086, 95% CI: 1.022-1.153, P=.008), compared to normal-flow, which were hypertension (OR: 15.9, 95% CI: 3.1-81.9, P=.001), higher septal E/E' ratio (OR: 1.16, 95% CI: 1.01-1.35, P=.043), lower septal S' velocity (OR: 0.204, 95% CI: 0.061-0.682, P=.010), and higher end-systolic wall stress (OR: 1.051, 95% CI: 1.001-1.104, P=.047). Overall, a third of the cohort experienced MACE, regardless of flow (log-rank 0.048, P=.827). However, aortic valve replacement (AVR) rates were lower in low-flow AS (20% vs 43%, P=.005). CONCLUSIONS: Low-flow AS despite normal LVEF appears similar to normal-flow in terms of LVEF deterioration and clinical outcomes in our Asian population. AVR rate was lower even though low-flow may not reflect less severe disease.

Central anticholinergic syndrome following dobutamine-atropine stress echocardiography.

We present a case of central anticholinergic syndrome following dobutamine-atropine stress echocardiography in an elderly female. Although atropine toxicity is a recognized complication of stress echocardiography, no case reports are currently available. The central nervous system side effects of atropine are varied in severity (mild cognitive impairment to severe coma) and spectrum (agitation or somnolence), and thus are often overlooked. Management includes prompt recognition, stopping the offending agent, providing supportive care, and consideration of physiostigmine. Atropine is used in up to 60% of dobutamine stress echocardiograms, and has the potential to cause morbidity.

Cardiovascular benefits of bariatric surgery.

The prevalence of obesity is increasing in the United States and worldwide, bringing with it an excess of morbidity and premature death. Obesity is strongly associated with both traditional cardiovascular risk factors as well as direct effects on hemodynamics and cardiovascular structure and function. In fact, cardiovascular disease is one of the major causes of morbidity and mortality in obese patients. Often, lifestyle and pharmacological weight-loss interventions are of limited efficacy in severely obese patients. Bariatric surgery has been shown to be a feasible option to achieve substantial and sustained weight loss in this group of patients. It is a safe procedure with low in-hospital and 30-day mortality rates even in groups that are considered higher risk for surgery (e.g., the elderly), especially if performed in high-volume centers. There is observational evidence that bariatric surgery in severely obese patients is associated with both a reduction of traditional cardiovascular risk factors as well as improvement in cardiac structure and function. Marked decreases in the levels of inflammatory and prothrombotic markers, as well as markers of subclinical atherosclerosis and endothelial dysfunction, are seen after bariatric surgery. This article summarizes the existing evidence regarding the cardiovascular benefits in patients following bariatric surgery.

Effectiveness of early cardiology undergraduate learning using simulation on retention, application of learning and level of confidence during clinical clerkships.

INTRODUCTION: This study aimed to assess the effectiveness of the use of a cardiopulmonary patient simulator in the teaching of second-year medical students. Effectiveness was measured in terms of the extent of knowledge retention and students' ability to apply the skills learned in subsequent real-life patient contact. METHODS: In this study, ten third-year medical students who had previously undergone simulator training as part of their second-year curriculum underwent an objective structured clinical examination (OSCE) and a multiple-choice question (MCQ) test to assess their ability to apply the knowledge gained during the simulator training when dealing with real patients. The performance of this group of students was compared with that of a group of ten fourth-year medical students who did not undergo simulation training. RESULTS: Although the third-year medical students performed well in the OSCE, they were outperformed by the group of fourth-year medical students, who had an extra year of clinical exposure. The MCQ scores of the two groups of students were similar. Post-simulation training survey revealed that students were generally in favour of incorporating cardiopulmonary simulator training in the preclinical curriculum. CONCLUSION: Cardiopulmonary simulator training is a useful tool for the education of preclinical medical students. It aids the translation of preclinical knowledge into real-life clinical skills.

Improvement in left ventricular function assessed by tissue Doppler imaging after aortic valve replacement for severe aortic stenosis.

INTRODUCTION: The effects of reduction of left ventricular (LV) systemic afterload following aortic valve replacement (AVR) for severe aortic valve stenosis (AS) were investigated, using echocardiography and tissue Doppler imaging (TDI). METHODS: We compared the preoperative and postoperative echocardiographic assessments of 23 patients with severe AS who had undergone isolated AVR (n = 13) or concomitant AVR with coronary artery bypass grafting (CABG) (n = 10). Conventional echocardiographic evaluations and TDI at the lateral mitral annulus were performed. RESULTS: Echocardiography was performed at a median of 120 (interquartile range: 66-141) days after AVR. There was significant reduction in aortic transvalvular mean pressure gradient after AVR. Although LV dimensions, mass and ejection fraction remained unchanged, LV diastolic and systolic functions improved (as observed on TDI). Early diastolic (E'), late diastolic (A') and systolic (S') mitral annular velocities increased significantly (p < 0.05). There was significant improvement in TDI-derived parameters among the patients who had isolated AVR, while among the patients who had concomitant AVR with CABG, only S' had significant improvement (p = 0.028). CONCLUSION: TDI was able to detect improvements in LV systolic and diastolic function after AVR for severe AS. There was less improvement in the TDI-derived diastolic parameters among patients who underwent concomitant AVR with CABG than among patients who underwent isolated AVR.

Reperfusion therapies reduce ischemic mitral regurgitation following inferoposterior ST-segment elevation myocardial infarction.

BACKGROUND: The presence of ischemic mitral regurgitation (IMR) after ST-segment elevation myocardial infarction (STEMI) portends a poorer prognosis. The possible influence of reperfusion therapy in restoring mitral valve competence in inferoposterior STEMI has not been well elucidated. METHODS AND RESULTS: We studied 423 consecutive patients with a first inferoposterior STEMI and determined the presence of IMR in patients treated with reperfusion therapy versus medical therapy. A primary percutaneous coronary intervention (PCI) was performed in 186 patients; 74 patients underwent thrombolysis, 63 patients had rescue PCI whereas 54 patients were treated medically. The mean time interval between STEMI presentation and echocardiography was 14 ± 27 days. Patients receiving reperfusion therapy had less moderate or severe IMR (2.5 vs. 11.1%, P=0.001). The presence of IMR between the primary PCI and the thrombolytic groups was similar (52.2 vs. 60.8%, P=NS). Left ventricular ejection fraction (47.7 ± 10.3 vs. 53.1 ± 11.4%, P<0.001) and infarct size (mean CK-MB) (271 ± 168 vs. 222 ± 151 U/l, P<0.001) were significantly worse in patients with IMR. Dominance of the coronary artery system, involvement of the right or the left coronary arteries, and the presence of triple-vessel disease did not correlate with the presence of IMR. After adjustment for age and left ventricular ejection fraction, there was a trend toward poorer survival and recurrent admission for heart failure at 1 year in patients with IMR (hazard ratio=2.4, 95% confidence interval 0.91-6.2, P=0.08). CONCLUSION: Both thrombolytic therapy and primary PCI were associated with decreased incidences of IMR following inferoposterior STEMI.

Trends in importation of communicable diseases into Singapore.

INTRODUCTION: Singapore is a transition country in Southeast Asia that is both vulnerable and receptive to the introduction and re-introduction of imported communicable diseases. MATERIALS AND METHODS: For a 10-year period between 1998 and 2007 we studied the trend, epidemiological characteristics, proportion of imported versus local transmission of malaria, viral hepatitis (hepatitis A and E), enteric fevers (typhoid and paratyphoid), cholera, chikungunya and SARS. RESULTS: Of a total of 4617 cases of the above selected diseases notified in Singapore, 3599 (78.0%) were imported. The majority of the imported cases originated from Southeast Asia and the Indian subcontinent. Malaria constituted the largest bulk (of which 95.9% of the 2126 reported cases were imported), followed by hepatitis A (57.1% of 1053 cases imported), typhoid (87.6% of 596 cases imported), paratyphoid (87.6% of 241 cases imported), and hepatitis E (68.8% of 231 cases imported). Furthermore, there were 14 cases of imported cholera, 6 cases of imported severe acute respiratory syndrome (SARS) and 13 cases of imported chikungunya. CONCLUSION: This study underlines that diseases such as malaria, viral hepatitis and enteric fever occur in Singapore mainly because of importation. The main origin of importation was South and Southeast Asia. The proportion of imported diseases in relation to overall passenger traffic has decreased over the past 10 years.

Framingham risk score inadequately predicts cardiac risk in young patients presenting with a first myocardial infarction.

INTRODUCTION: The Framingham Risk Score (FRS) is a well-validated epidemiologic tool used to assess the risk for a fi rst cardiac event. Because young patients presenting with a fi rst myocardial infarction (MI) tend to have less significant risk profiles compared with older patients, we hypothesized that FRS may underestimate cardiac risk in these patients. MATERIALS AND METHODS: We studied 1267 patients between January 2002 and November 2007 presenting with a fi rst MI. Patients with pre-existing diabetes mellitus and vascular disease were excluded. FRS was calculated for each patient. Patients were divided based on their age: group A (<40 years), group B (40 to 64 years) and group C (> or =65 years). RESULTS: The mean age was 54.7 +/- 11 years, 88.4% of the patients were males. Younger patients were more likely to be assigned with lower scores. Based on FRS, 63.0%, 29.3% and 14.2% of group A, B and C patients were classified as low risk (10-year risk for cardiac events<10%) respectively, P <0.001. The sensitivity of FRS in identifying at least intermediate risk subjects (10-year risk for cardiac events >10%) was 37.0% in group A vs 85.8% in group C (P <0.001). The incidence of newly diagnosed diabetes mellitus was higher in younger patients (12.0% vs 13.2% vs 7.1 % in groups A, B and C respectively, P = 0.027). CONCLUSIONS: FRS inadequately predicts cardiac risk in young patients presenting with a fi rst MI. This could be because a significant proportion of these young patients have undiagnosed diabetes mellitus, a coronary artery disease risk equivalent.