Reader response: Systematic review and meta-analysis of cardiac involvement in mitochondrial myopathy
JosefFinsterer, Neurologist, KAR
Submitted August 21, 2019
Though stimulating, the article by Quadir et al. about a meta-analysis of 21 studies on cardiac involvement in mitochondrial disorders (MIDs)[1] has shortcomings.
The first is that left ventricular hypertrabeculation/noncompaction (LVHT) was not included. In a study of 172 patients with LVHT, 19 had a MID.[2] Since MIDs are the group of genetic disorders most frequently associated with LVHT,[3] it cannot be neglected. Additionally, LVHT requires treatment and has a strong impact on the outcome of MID patients. This is because of its complications, cardioembolic events, heart failure, ventricular arrhythmias, and sudden cardiac death.
Also missing is late gadolinium enhancement (LGE) in the left ventricular myocardium.[4] LGE reflects cardiomyopathy, fibrosis, myocarditis, amyloidosis, or scaring. LVHT with LGE has a worse outcome than LVHT without LGE.
Finally, Takotsubo cardiomyopathy (TTC) needs to be included, as MID patients are less stress-resistant than others due to their reduced anti-oxidative capacity to compensate for oxidative stress. This is because epilepsy is a frequent trigger of TTC and epilepsy is a frequent phenotypic feature of MIDs.[5] Though usually associated with a beneficial outcome, TTC needs to be discussed with regard to sudden unexplained death (SUDEP). TTC is considered as one of the possible mechanisms triggering SUDEP.
Quadir A, Pontifex CS, Lee Robertson H, Labos C, Pfeffer G. Systematic review and meta-analysis of cardiac involvement in mitochondrial myopathy. Neurol Genet 2019;5:e339.
Stöllberger C, Blazek G, Wegner C, Finsterer J. Neurological comorbidity affects prognosis in left ventricular hypertrabeculation/noncompaction. Heart Lung 2012;41:594-8.
Finsterer J. Cardiogenetics, neurogenetics, and pathogenetics of left ventricular hypertrabeculation/noncompaction. Pediatr Cardiol 2009;30:659-81.
Boban M, Pesa V, Gabric ID, et al. Auxiliary diagnostic potential of ventricle geometry and late gadolinium enhancement in left ventricular non-compaction; non-randomized case control study. BMC Cardiovasc Disord 2017;17(1):286.
Desai R, Singh S, Patel U, et al. Frequency of takotsubo cardiomyopathy in epilepsy-related hospitalizations among adults and its impact on in-hospital outcomes: A national standpoint. Int J Cardiol 2019. pii: S0167-5273(19)32472-6.
Though stimulating, the article by Quadir et al. about a meta-analysis of 21 studies on cardiac involvement in mitochondrial disorders (MIDs)[1] has shortcomings.
The first is that left ventricular hypertrabeculation/noncompaction (LVHT) was not included. In a study of 172 patients with LVHT, 19 had a MID.[2] Since MIDs are the group of genetic disorders most frequently associated with LVHT,[3] it cannot be neglected. Additionally, LVHT requires treatment and has a strong impact on the outcome of MID patients. This is because of its complications, cardioembolic events, heart failure, ventricular arrhythmias, and sudden cardiac death.
Also missing is late gadolinium enhancement (LGE) in the left ventricular myocardium.[4] LGE reflects cardiomyopathy, fibrosis, myocarditis, amyloidosis, or scaring. LVHT with LGE has a worse outcome than LVHT without LGE.
Finally, Takotsubo cardiomyopathy (TTC) needs to be included, as MID patients are less stress-resistant than others due to their reduced anti-oxidative capacity to compensate for oxidative stress. This is because epilepsy is a frequent trigger of TTC and epilepsy is a frequent phenotypic feature of MIDs.[5] Though usually associated with a beneficial outcome, TTC needs to be discussed with regard to sudden unexplained death (SUDEP). TTC is considered as one of the possible mechanisms triggering SUDEP.
Footnote
For disclosures, please contact the editorial office at journal@neurology.org.
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