MRI for post-vaccine myocarditis, review of 532 cases, peer-reviewed
Echocardiogram missed 59.8% of cases of myocarditis, and CT was even worse
Keshavarz et al (2022) (link below) appears to be a well-organized systematic review of covid vaccine myocarditis cases where cardiac MRI was used to confirm the diagnosis. They appeared to be less interested in clinical outcomes, noting simply that 3 patients died and over 90% were discharged from hospital.
However, for diagnosis, there is a substantial amount of data here. Much raw data is included to enable further analysis.
IS CT USEFUL FOR DIAGNOSING POST COVID VACCINE MYOCARDITIS? APPARENTLY NOT
In supplementary table 2, they include imaging findings for various modalities that were used in the studies. I spotted CT results for 24 studies in this table, comprising 27 patients. 24 of 27 scans were normal, yielding a sensitivity of 11%. CT with contrast does not appear to be at all helpful for diagnosis of post-vaccine myocarditis based on this data.
IS ECHO USEFUL FOR DIAGNOSING POST VACCINE MYOCARDITIS? SOMEWHAT
In their review of echocardiogram findings, the authors note:
“Echocardiography was reported in 73% (388 of 532) of cases with normal findings in 228 cases. Abnormal echocardiographic findings in 41.2% (160 of 388) of cases included pericardial effusion 5.1% (20 of 388), focal and general hypokinesia 12.1% (47 of 388), reduction in mono or biventricular ejection fraction 21.9% (85 of 388), and others were not reported. The left ventricle ejection fraction (LVEF) was reported in 197 cases of which 32% (63 of 197) were less than 50% and 68% (134 of 197) cases were greater than 50%.” (Some of these were not mild cases, in other words)
1) echo was much less sensitive at picking up myocarditis: 41.2% sensitivity
2) significant cardiac impairment was seen: impaired left ejection fraction in 63 cases.
A separate analysis should be written regarding echo findings in post-covid vaccine myocarditis. This paper provides useful data to work from.
SUMMARY: The most important takeaway for me as a clinician, and one that I would want to share with my medical colleagues (are you out there, colleagues?) is that echocardiaograms will miss post-vaccine myocarditis frequently - 60% of the time, according to this study. I have no reasons to suspect that this study is exaggerating the utility of MRI, nor diminishing the utility of echocardiograms, in myocarditis diagnosis.
Therefore, cardiac MRI must find its way into clinical practice much more frequently in cases of post-vaccine chest pain.
I welcome your comments and critiques.