Author + information
- Matthias G. Friedrich, MD⁎ ()
- ↵⁎Reprint requests and correspondence:
Dr. Matthias G. Friedrich, Montreal Heart Institute, Cardiology, 5000 Rue Belanger, Montreal, Quebec H1T 1C8, Canada
- cardiac magnetic resonance imaging
- endomyocardial biopsy
- left ventricular reverse remodeling
- recent-onset dilated cardiomyopathy
Prediction is very difficult, especially about the future.
—Niels Bohr (1885–1962) (1)
Any diagnostic exam is a snapshot in time and thus cannot easily predict dynamic processes without additional context. This is often given by the known clinical course of a disease; thus, based on their knowledge and experience, clinicians combine their clinical assessment with the results of a diagnostic test to make a therapeutic decision.
Recent-onset dilated cardiomyopathy, generally representing an inflammatory response to viral infection, is an example of a dynamic disease, because it is characterized by acute regional and/or global inflammation with hyperemia, edema, cell death, and dysfunction, which may or may not recover. The reversibility of tissue pathology and associated dysfunction is not only determined by the severity of the initial inflammatory response, but is also subject to mechanical stress caused by increased filling pressures, with subsequently high regional or global wall stress. The immune response can vary dramatically between individuals and depend on the general immune status of the patient and the specific immune reaction to the specific trigger. Importantly, these processes are local in nature and thus, especially in internal organs, are not amenable to a diagnosis through a physical exam or even systemic markers such as blood tests. Thus, a diagnostic test ideally also provides information on function, mechanical stress (especially because filling pressures can to some extent be modified by pharmacological interventions), and tissue pathology. This explains the pivotal role of imaging for clinical decision making in acute disease.
In this issue of the Journal, Kubanek et al. (2) report a study using cardiovascular magnetic resonance (CMR), known cardiac serum biomarkers, and endomyocardial biopsy to predict left ventricular reverse remodeling in patients with recent-onset dilated cardiomyopathy. When comparing the predictive value of these markers for left ventricular recovery, they found that a smaller extent of irreversible injury (as measured in late gadolinium enhancement images) and myocardial edema, both acquired at baseline, were the strongest independent predictors, whereas after 3 months, the latest brain natriuretic peptide (BNP) was the only independent predictor. The authors conclude that CMR and serial BNP are the most accurate predictors for left ventricular reverse remodeling in recent-onset dilated cardiomyopathy.
The paper has some limitations: The sample size is limited, with only 15 patients considered as having inflammation. Patient selection was based on the presence of left ventricular dilation, and thus may have missed patients with slowly evolving left ventricular dilation. The sample may only represent a subgroup of patients with subacute or chronic disease. The clinical onset of disease was beyond the time expected for acute myocarditis, also suggested by the observation that left ventricular size did not differ between inflammatory and idiopathic patients and by the lack of a difference with regard to markers of acute disease (high-sensitivity troponin T, viral genome presence, BNP, and C-reactive protein) between inflammatory and idiopathic cardiomyopathy as defined by biopsy. Therefore, the results may only be applicable in patients with suspected chronic inflammation as defined by biopsy.
Biopsy, used as a gold standard, was obtained from the right ventricular septum, a location that is known to be a rather infrequent site of inflammation-induced injury and even less so in patients with parvovirus B19 (3), the virus reported in 25 of the patients of this study. Therefore, the value of biopsy to serve as a standard of truth is unclear.
Furthermore, the authors did not match the location of CMR findings of irreversible injury with biopsy. Finally, the paper does not well reflect a clinical “real-life” scenario, since a reader would not look at the results of edema and scar separately, but take both into account. Thus, the combined use of these criteria may have further improved the predictive value of CMR.
Yet, despite these shortcomings, the paper provides important comparative data on the predictive value of various markers acquired at different time points. The work underscores the value of CMR as a uniquely comprehensive tool for diagnosing myocardial disease, which not only provides a precise snapshot of the current status, but also delivers several strong predictive markers.
Regional myocardial edema as assessed by edema-sensitive CMR in the absence of matching irreversible injury is a very strong predictor of functional recovery. This is especially impressive in stress-induced cardiomyopathy, where the recovery of an extensive wall motion abnormality can be predicted by the presence of edema in the absence of regionally matching irreversible injury (4).
Regional persistence of gadolinium as the key interstitial MR contrast agent as demonstrated by scar-sensitive CMR (“late gadolinium enhancement”) indicates irreversible injury and thus is associated with a lack of functional recovery, acting as a predictor for a lack of functional recovery in acute myocardial inflammation. Of note, this finding has also been proven as a strong predictor of mortality (5).
The diagnostic and prognostic value of global left ventricular dysfunction, typically reported as ejection fraction, has been demonstrated. Furthermore, the presence of regional wall motion abnormalities has a strong predictive value even in the general population (6).
It is important to keep in mind that all these markers can be easily assessed during 1 scan of <25 min.
There is little doubt that in patients with recent-onset cardiomyopathy, as in other acute myocardial diseases, functional recovery can generally be predicted by a single CMR scan if done at the time of clinical presentation. Clinical trials using standardized protocols in larger samples are warranted. If these results can be confirmed, the prediction of the future, at least in acute myocardial disease, may not be that difficult after all.
The author has reported that he has no relationships relevant to the contents of this paper to disclose.
↵⁎ Editorials published in the Journal of the American College of Cardiology reflect the views of the authors and do not necessarily represent the views of JACC or the American College of Cardiology.
- American College of Cardiology Foundation
- Bohr N.
- Kubanek M.,
- Sramko M.,
- Maluskova J.,
- et al.
- Mahrholdt H.,
- Wagner A.,
- Deluigi C.C.,
- et al.
- Grün S.,
- Schumm J.,
- Greulich S.,
- et al.
- Yan R.T.,
- Bluemke D.,
- Gomes A.,
- et al.