The American journal of cardiology
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Editorial Comment Comparative Study
Lidocaine and sustained monomorphic ventricular tachycardia: fact or fiction.
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Comparative Study Clinical Trial Controlled Clinical Trial
Comparison of impedance cardiography with thermodilution and direct Fick methods for noninvasive measurement of stroke volume and cardiac output during incremental exercise in patients with ischemic cardiomyopathy.
In the last decade, an inexpensive and simple noninvasive method (i.e., transthoracic electrical bioimpedance cardiography, has been tested in healthy subjects and patients with various heart disease for measuring stroke volume and cardiac output at rest and/or during exercise. However, the results are still controversial, especially when measurements are obtained during exercise and data on reproducibility during exercise are lacking. Twenty-five consecutive patients (20 men and 5 women, mean age 48 +/- 9 years) in sinus rhythm with documented coronary artery disease and a previous myocardial infarct were studied. ⋯ There were no significant differences in stroke volume and cardiac output in the 3 techniques at any matched work rate. There was no significant difference between measurements obtained by 2 experienced observers or between those obtained on 2 exercise tests performed on 2 different days. These results demonstrate that impedance cardiography is a noninvasive, simple, accurate, and reproducible method of measurement of cardiac output and stroke volume over a wide range of workloads.
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In summary, ST-segment elevations on the admission electrocardiogram not only diagnose acute myocardial infarction but also provide predictive information with respect to developing infarct size and left ventricular remodeling as well as survival.
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Clinical Trial
Troponin T as a marker for myocardial ischemia in patients undergoing major noncardiac surgery.
To assess the diagnostic performance of cardiac troponin T as a marker for myocardial injury in patients undergoing major noncardiac surgery, we prospectively collected preoperative and postoperative clinical data, including measurements for creatine kinase (CK), CK-MB, and troponin T for 1,175 patients undergoing major noncardiac surgery. Acute myocardial infarction was diagnosed in 17 patients (1.4%) by a reviewer who was blinded to troponin T data and who used CK-MB and electrocardiographic criteria to define acute myocardial infarction. Other predischarge major cardiac complications were detected for another 17 patients. ⋯ Among patients without myocardial infarction, troponin T was elevated in 62% of patients with and in 15% of patients without major cardiac complications. Receiver-operating characteristic analysis indicated that troponin T had a performance for the diagnosis of acute myocardial infarction similar to CK-MB, and a significantly better correlation with other major cardiac complications in patients without definitive infarction. Future research should seek to determine the significance of troponin T elevations in patients without complications.
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Fetal transesophageal and intracardiac echocardiography by utilizing ultrasound technology permits accurate definition of cardiac anatomy in fetal sheep. Because fetal transesophageal echocardiography is less invasive than intracardiac echocardiography, it has the potential to serve as a monitoring tool for currently developed open and fetoscopic fetal cardiac interventions.