Background The incidence and management of trastuzumab-mediated cardiotoxicity outside of clinical trials has not been well described. Objective and methods The aim of the study was to retrospectively evaluate the incidence of cardiac dysfunction, characterize its natural history, and identify the degree of reversibility using cardiac MRI, in a population of HER-2 positive breast cancer patients receiving trastuzumab in the adjuvant setting. Results Out of 152 patients (mean age 52 +/- 10 years), 36 (24%) developed trastuzumab mediated cardiomyopathy, the majority asymptomatic. Factors that predicted the development of trastuzumab mediated cardiac dysfunction were a pre-existing history of hypertension, smoking history, and a family history of coronary artery disease. Within 3 months of treatment with trastuzumab, there was a difference in LVEF between the normal cohort and those patients who developed LV systolic dysfunction (61 +/- 5% vs. 51 +/- 8%, P < 0.01). During the 6-month-followup, 34/36 patients demonstrated subepicardial linear delayed enhancement of the lateral wall of the left ventricle on cardiac MRI, suggesting trastuzumab induced myocarditis. Conclusion Approximately 1 in 4 women may develop LV systolic dysfunction after treatment with adjuvant trastuzumab, necessitating careful patient selection and close serial monitoring using noninvasive cardiac imaging.

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An elevation of cardiac injury markers including creatinine kinase (CK), myoglobin (Myo) and cardiac troponin T (cTnT) has been observed in elite athletes following strenuous exercise. The mechanism and significance of this observation however have not been fully elucidated. The goals of this study were: 1) to determine whether these changes in biomarkers also occur in a large, heterogeneous group of non-elite athletes; and 2) to identify possible clinical or biochemical associations. We recruited 129 non-elite runners in 2006, 61 individuals who were taking part in the half (13.1 miles) marathon and 68 individuals participating in the full (26.2 miles) marathon. Demographic data and blood samples were collected for analysis of CK, Myo, cTnT, and Creatinine (Cr) levels within two hours of race start, at race completion, and 1-h post-race for both patient cohorts. In the 61 individuals (40 males, 40+/-12 yrs) completing the half marathon in a mean time of 150+/-20 min, 90.3%, 65.2%, and 30.6% of the subjects exhibited significant elevations in Myo, CK, and cTnT, respectively immediately post race and 100%, 74.9% and 45.9% in the same biomarkers one hour-post race. In the 68 individuals (44 males, 42+/-14 yrs) completing the full marathon in a mean time of 310+/-30 min, 95.3%, 70.2% and 35.7% exhibited significant elevations in Myo, CK and cTnT respectively immediately post race and 100%, 78.5% and 52.8% in the same biomarkers one hour-post race. The elevation in cTnT levels post-race were modestly associated with the time required to complete the race for the entire cohort of marathon runners. The serum levels of Cr, CK, and Myo post-race did not correlate however with age, sex, BMI, level of training, or prior marathon experience. Elevations of cardiac injury markers in non-elite athletes are extremely common following the completion of endurance events and correlate to the increased endurance time. Whether the increase in the levels of these enzymes represents true myocardial injury or a result of the release of cTnT from the myocytes requires further investigation.