A digital network for long-distance echocardiographic image and data transmission in clinical trials: the CEDIM (Carnitina, Ecocardiografia Digitalizzata, Infarto Miocardico) study experience

Transition to an all-digital echocardiography laboratory: a large, multi-site private cardiology practice experience

Acquisition, interpretation, and storage of digital echocardiographic images has many advantages over the standard videotape-based method. Archival, transmission, and comparative interpretation are all optimized with digital echocardiography. A study performed at one site can be immediately available for viewing and analysis at another site by means of standard data transfer technology. Echocardiograms can be interpreted in the context of prior studies, which are readily available for side-by-side comparison. The transition to an all-digital laboratory involves the commitment of persons at multiple levels in the cardiology practice, including administrators, information technology specialists, sonographers, and physicians. Quality of patient care, use of physicians' and sonographers' time, and long-term financial benefit are all areas where improvement may be realized with the use of digital echocardiography. We present our experience in the development of an all-digital echocardiography laboratory, and we conclude that digital echo-cardiography is practical and can be implemented readily in a clinical setting. We performed several correlative analyses during this transition to validate the consistency and accuracy of digital interpretation compared with those of analog methods. The transition process from analog (videotape) to digital, including full wide area network exchange, took approximately 8 months. As technology advances, issues surrounding storage, comparison, and acquisition formats will continue to develop. We hope that our experience will help others make the transition to the digital environment and benefit from the ease of image access, the ability to comparatively interpret echocardiograms, and the superior image quality afforded by this advancement.

Myocardial infarction and left ventricular remodeling: results of the CEDIM trial. Carnitine Ecocardiografia Digitalizzata Infarto Miocardico

Left ventricular dilatation after acute myocardial infarction (MI) is a powerful predictor of progressive functional deterioration, culminating in heart failure and death. The most important determinants of post-MI left ventricular remodeling are the size of the infarct, the degree of residual stenosis in the infarct-related artery, and the viability of the infarct zone. In addition to reperfusion therapy and angiotensin-converting enzyme inhibition, metabolic intervention with L-carnitine may represent a therapeutic approach for preventing left ventricular dilatation and preserving cardiac function. Ongoing studies with early metabolic intervention with carnitine in the acute phase of infarction may prove successful in protecting the microcirculation against ischemic damage and enhancing its ability to respond to blood flow resumption. The results of the multicenter, randomized, double-blind Carnitine Ecocardiografia Digitalizzata Infarto Miocardico (CEDIM) trial suggest that the early and long-term administration of L-carnitine attenuates progressive left ventricular dilatation after acute anterior MI. Results show significant, consistent reductions in end-diastolic volume and end-systolic volume in patients who received L-carnitine compared with placebo. The ongoing CEDIM-2 trial (projected 4000 patients with acute MI) will assess the efficacy of L-carnitine in reducing the combined incidence of death and heart failure at 6 months. In addition to standard reperfusion therapy and angiotensin-converting enzyme inhibition, metabolic intervention with L-carnitine may be a therapeutic approach for preventing left ventricular dilatation and preserving cardiac function by limiting infarct size, decreasing residual stenosis in the infarct-related artery, and increasing viability of the infarct zone.

A comparison of the interpretation of digitized and videotape recorded echocardiograms

Conventional echocardiograms are typically recorded on videotape and later reviewed and interpreted by a physician. Although videotape recording is an excellent medium for this purpose, it does have several disadvantages, which may be overcome by digital storage. This study compared the diagnostic accuracy of digitized and videotape recorded echocardiograms. Echocardiographic examinations (n = 110) were recorded simulta-neously on videotape and were digitized with a commercially available frame grabber system. Images were transmitted by an Ethernet link to the network-based computer system and compressed with a nondestructive compression algorithm. Images were reviewed on a personal computer. Images were interpreted by 3 observers, and differences in interpretation were documented. There were 274 findings in 110 patients. Exact agreement in interpretation was found in 83%. A major discrepancy occurred in 2%, and a minor discrepancy occurred in 15%. Most discrepancies occurred in the setting of valvular heart disease. When compared with a consensus interpretation, no significant difference was seen in the number of errors between the digital and videotape interpretation. We conclude that the interpretation of a properly recorded digitized echocardiographic examination yields interpretations equivalent to those of videotape recordings.

Effects of L-carnitine administration on left ventricular remodeling after acute anterior myocardial infarction: the L-Carnitine Ecocardiografia Digitalizzata Infarto Miocardico (CEDIM) Trial

OBJECTIVES

This study was performed to evaluate the effects of L-carnitine administration on long-term left ventricular dilation in patients with acute anterior myocardial infarction.

BACKGROUND

Carnitine is a physiologic compound that performs an essential role in myocardial energy production at the mitochondrial level. Myocardial carnitine deprivation occurs during ischemia, acute myocardial infarction and cardiac failure. Experimental studies have suggested that exogenous carnitine administration during these events has a beneficial effect on function.

METHODS

The L-Carnitine Ecocardiografia Digitalizzata Infarto Miocardico (CEDIM) trial was a randomized, double-blind, placebo-controlled, multicenter trial in which 472 patients with a first acute myocardial infarction and high quality two-dimensional echocardiograms received either placebo (239 patients) or L-carnitine (233 patients) within 24 h of onset of chest pain. Placebo or L-carnitine was given at a dose of 9 g/day intravenously for the first 5 days and then 6 g/day orally for the next 12 months. Left ventricular volumes and ejection fraction were evaluated on admission, at discharge from hospital and at 3, 6 and 12 months after acute myocardial infarction.

RESULTS

A significant attenuation of left ventricular dilation in the first year after acute myocardial infarction was observed in patients treated with L-carnitine compared with those receiving placebo. The percent increase in both end-diastolic and end-systolic volumes from admission to 3-, 6- and 12-month evaluation was significantly reduced in the L-carnitine group. No significant differences were observed in left ventricular ejection fraction changes over time in the two groups. Although not designed to demonstrate differences in clinical end points, the combined incidence of death and congestive heart failure after discharge was 14 (6%) in the L-carnitine treatment group versus 23 (9.6%) in the placebo group (p = NS). Incidence of ischemic events during follow-up was similar in the two groups of patients.

CONCLUSIONS

L-Carnitine treatment initiated early after acute myocardial infarction and continued for 12 months can attenuate left ventricular dilation during the first year after an acute myocardial infarction, resulting in smaller left ventricular volumes at 3, 6 and 12 months after the emergent event.