Cardiomyopathy (VVV) Study Basics

Cardiomyopathy (VVV) is a trial of variability of echocardiographic left ventricular mass, volume and ejection fraction in pediatric patients with congestive cardiomyopathy. Echocardiograms are the primary method to evaluate the size of the heart and how it functions. Healthcare providers did not know how reproducible some of the measurements were, especially in children. This study was done to help us understand why there might be errors in measurements and the true change in heart function values over time. The study began on May 16, 2005 and the last patient was enrolled in July 2007 with 131 individuals enrolled.

Who was in the study?

Individuals who:
  • Were less than 22 years of age.
  • Had a diagnosis of dilated cardiomyopathy for more than 2 months.
  • Had follow-up at the same institution for 3-13 months after enrollment.
  • Were not on the transplant list.
  • Were having an echocardiogram done.

What happened during the study?

Each qualified person had data collected on labs, tests and procedures that were done as part of routine clinical care. A second set of measurements were done when each routine echocardiogram was performed during a one year period of time (with at least 3 months in between each test).

What were the results of the study?

  • Beat averaging and a single core lab observer improved the reproducibility of echocardiographic measurements in children with dilated cardiomyopathy. Certain measurements were highly reproducible, while others, despite beat averaging, were poorly reproducible.
  • M-mode had similar or greater reproducibility in both intrareader and interreader settings for LV dimensions, shortening fraction (SF), and most wall thicknesses. In contrast, 2D reproducibility was similar or better for nearly all variables in the interacquisition setting but not for SF. Interacquisition variability was approximately twice the intrareader variability. LV dimensions by either modality consistently had high reproducibility and had the highest agreement between modalities. Except for LV dimensions, M-mode and 2D values should not be used interchangeably due to poor agreement.
  • The reproducibility of LV size and functional measurements in children with dilated cardiomyopathy is highest using the 5/6AL algorithm and can be further improved by using the 3BA. However, values derived from different algorithms are not interchangeable.
  • In pediatric patients with dilated cardiomyopathy, compared with dimension and area methods, left ventricular measurements by volume method have the best reproducibility in settings where assessment is not performed by the same personnel.