Echocardiography Identifies Risks of Arrhythmia, Cardiac Failure in Pediatric Myocarditis

By Marilynn Larkin

July 06, 2021

NEW YORK (Reuters Health) - Left ventricular (LV) deformation assessed by echocardiographic strain measurements identified children with myocarditis at risk for developing arrhythmias and cardiac failure in a single center, retrospective study.

"Strain imaging by speckle tracking echocardiography has become an increasingly useful modality to monitor changes in LV deformation and myocardial function," Dr. Cathleen Pruitt of the University of Utah in Salt Lake City told Reuters Health by email. "Numerous adult and pediatric studies demonstrate that strain imaging allows for early detection of subclinical LV dysfunction in a variety of clinical states."

Other studies have shown the utility of strain imaging in adult and pediatric myocarditis, she said. However, the current study "is novel in that we evaluated the association of LV strain and arrhythmia in children hospitalized with acute myocarditis."

"We found that LV strain was significantly reduced in the patients with arrhythmia in acute myocarditis, she noted, "whereas echocardiographic LV EF and shortening fraction failed to discriminate between the arrhythmia and no arrhythmia groups."

"A cutoff value of LV global longitudinal strain (GLS) of -11 predicted arrhythmia in our cohort," she said. "We were curious if LV strain could also predict cardiac failure in this patient population. Indeed, a cutoff value of LV GLS of -7 predicted cardiac failure. This finding intrigued us as LV strain may be able to predict the need for mechanical cardiac support in the early stages of acute myocarditis."

As reported in The American Journal of Cardiology, Dr. Pruitt and colleagues assessed the relationship between LV deformation measured by two-dimensional speckle tracking echocardiography (2D-STE), and arrhythmia in children and adolescents hospitalized with acute myocarditis from 2008-2018.

Arrhythmias were defined as non-sustained or sustained ventricular tachycardia or ventricular fibrillation; sustained supraventricular tachycardia (SVT); high-grade or complete heart block; or any arrhythmia treated with an antiarrhythmic medication.

Sixty-six patients were included in the analysis, of whom 23 (35%) had arrhythmias, with SVT being the predominant type (74%).

Global and regional strain indices were reduced in the arrhythmia vs. no arrhythmia groups: LV GLS (-8.9 vs. -13.7); basal inferior/septal (-10.7 vs. -16.4); basal anterior/lateral (-7.1 vs. -9.4); and mid-inferior/septal segments (-9 vs. -14.1).

After controlling for age, reductions in GLS and segmental strain in the two basal and two mid-segments were associated with increased arrhythmia occurrence.

The authors note that a GLS worse than -11 was a "strong predictor" of arrhythmia in the setting of acute myocarditis and that "LV GLS worse than -7.6 was associated with cardiac failure, allowing 2D-STE monitoring to potentially identify patients who require close surveillance for acute decompensation or use of mechanical cardiac support."

Dr. Pruitt said, "With the advent of the COVID-19 pandemic, we have seen a multitude of children with cardiovascular manifestations of the disease. A portion of these children develop myocardial dysfunction as well as arrhythmias."

"The prognosis of these affected children is unclear, and there is likely a role for strain imaging in guiding clinical management," she said. "Additionally, there are now reports of myocarditis associated with the COVID-19 vaccine. Strain imaging may be useful in prognostication in this patient population, as well."

Dr. Cara Garofalo, Chair, Pediatric Cardiology at Deborah Heart and Lung Center in Browns Mills, New Jersey, commented to Reuters Health by email, "Myocardial strain by 2D speckle tracking is a valuable tool in the assessment of regional and global myocardial function, with expanding clinical applications in pediatrics."

"For children with myocarditis, echo is one of the first tools used at the time of presentation," she noted. "The ability to identify early on patients at potentially increased risk for arrhythmia by impaired myocardial strain... would be an important step in assessment and risk stratification and would inform clinical decision-making."

"The results of this study should set the stage for a larger prospective study," Dr. Garofalo concluded.

SOURCE: The American Journal of Cardiology, online June 18, 2021.