Coronary plaque instability in severe acute respiratory syndrome.

In his second week of severe acute respiratory syndrome (SARS) illness, a patient developed an unusually complicated course of acute coronary syndrome. One day after initial stabilization of a non-ST-elevated anterior myocardial infarction (MI), he sustained an ST-elevated anterior MI. Eight hours after emergency coronary intervention to the culprit lesion, he developed another ST-elevated MI in the inferior territory. Acute inflammation and cytokine storm in the immunopathological phase of SARS may play a role in coronary plaque instability. Physicians should be alert to this potentially fatal complication and adopt appropriate vigilant and aggressive management strategies.

Preparedness of the cardiac catheterization laboratory for severe acute respiratory syndrome (SARS) and other epidemics.

Severe acute respiratory syndrome (SARS) is a highly contagious disease that has led to large hospital and community outbreaks, necessitating stringent infection control in its management. Among 90 SARS patients in our institution in the 2003 outbreak, 2 underwent cardiac catheterization. We report the personal respiratory protection and environmental control measures implemented to minimize the risk of droplets spread during these procedures, including re-engineering of the ventilation system of the cardiac catheterization laboratory (CCL). The report highlights the importance of collaboration of CCL personnel with relevant hospital engineering and management teams to develop a contingency infection control plan to prepare for future outbreaks of SARS or other epidemics.

Partial normalization of the heart rate response to exercise after cardiac transplantation: frequency and relationship to exercise capacity.

OBJECTIVE: To determine the frequency of partial normalization of the heart rate response to graded exercise and its relationship to exercise capacity in cardiac transplant recipients. SUBJECTS AND METHODS: The study subjects were 95 adults (77 men, 18 women) who were available to perform a cardiopulmonary exercise test 1 year after orthotopic cardiac transplantation, which occurred between June 1988 and September 1998. All subjects received standard immunosuppressant medications. At the time of the exercise tests, the mean +/- SD age of the subjects was 49+/-14 years. The mean +/- SD resting left ventricular ejection fraction was 62%+/-8%. All subjects participated in a 6- to 8-week supervised exercise program, starting no later than 1 month after surgery. Subjects were given an exercise prescription for independent exercise training after finishing the supervised program. Self-reported weekly exercise training had a median value of 90 minutes (interquartile range, 0-210 minutes). Symptom-limited graded exercise was performed on a treadmill, with breath-by-breath analysis of expired air. RESULTS: For the entire cohort, peak exercise oxygen uptake was 19.9+/-4.8 mL x kg(-1) x min(-1) (61%+/-15% of age and sex predicted). Thirty-two subjects (34%) had a partially normalized heart rate response to graded exercise. The frequency was similar for men (25/77 [33%]) and for women (7/18 [39%]) and was independent of recipient or donor age. Peak exercise heart rate (147+/-18 vs 134+/-21 beats/min; P=.008) and heart rate reserve (46+/-15 vs 33+/-15 beats/min; P<.001) were greater for subjects with a partial normalization of heart rate response. Peak exercise oxygen uptake was similar for subjects with or without partial normalization of the heart rate response (20.9+/-5.8 vs 19.4+/-4.2 mL x kg(-1) x min(-1); P=.22). Submaximal exercise oxygen uptake during the first few minutes of exercise was also not affected by normalization of the heart rate response. CONCLUSION: At 1 year after cardiac transplantation, approximately one third of subjects had partial normalization of the heart rate response to graded exercise. However, a higher peak exercise heart rate and a larger heart rate reserve did not result in better aerobic exercise capacity.

Clinical predictors of exercise capacity 1 year after cardiac transplantation.

BACKGROUND: The exercise capacity of cardiac transplant recipients is reduced compared with normal controls. However, clinical variables predictive of post-transplant exercise capacity have not been well defined. The objective of the present study was to identify clinical features predictive of post-transplant exercise capacity. METHODS: Ninety-five cardiac transplant recipients underwent cardiopulmonary testing at 1 year after transplant. The exercise parameters were compared with both pre-transplant values and normal subjects. The relationships between exercise parameters and clinical characteristics were analyzed. RESULTS: Mean peak oxygen consumption (VO(2)) and exercise test duration at 1-year post-transplant improved significantly from 16.4 to 19.9 ml/kg/min and 5.5 to 7.6 minutes, respectively (p < 0.001), but were significantly lower than for normal controls (peak VO(2) 34.0 ml/kg/min; exercise duration 11.2 minutes; p < 0.001). Age- and gender-adjusted VO(2) was 54% of predicted. Pre-operative body weight correlated strongly with post-transplant weight (r = 0.80, p < 0.001). Significant recipient predictors of 1-year post-transplant peak VO(2) identified by multivariate regression analysis were age, male gender, body mass index, exercise peak heart rate and duration of post-operative intensive care. Donor variables did not contribute significantly to post-transplant peak VO(2). CONCLUSIONS: Peak VO(2) improved after cardiac transplantation but remained significantly impaired compared with normal subjects. In estimating the impact of cardiac transplantation on exercise capacity the most important pre-transplant factors to consider are age, gender and height and weight (or, alternatively, body mass index).

Behçet's aortitis and aortic regurgitation: a report of two cases.

Behçet's disease is a rare systemic vasculitis that may lead to neurologic complications and rare manifestations of aortitis and aortic regurgitation. We report 2 cases of Behçet's aortitis and aortic regurgitation. The first patient presented with acute stroke. Recognition of acute aortitis on echocardiography led to the diagnosis of vasculitis as the cause of the cerebral event. This case highlights the echocardiographic features of aortic root pathology from acute aortitis to subsequent aortic valve perforation. In both cases, severe aortic regurgitation necessitated aortic valve replacement. Both were complicated by valve dehiscence requiring reoperation, illustrating the postoperative morbidity in this inflammatory condition.