Noncompaction patients may profit from neurological investigations
With interest we read the article by McMahon et al. about the application of tissue Doppler imaging (TDI) in assessing the prognosis of children with left ventricular hypertrabeculation/noncompaction (LVHT).
We have, however, several questions and concerns:
There are only limited experiences in the follow-up of patients with LVHT and the prognosis is largely unknown. The “undulating phenotype” of the cardiac abnormalities is a feature of LVHT, not exclusively found in children, but also in adults.
With interest we recognized that the applied diagnostic criteria are a fruitful combination of Jenni’s and our criteria. Recently we proposed to classify LVHT cases fulfilling both criteria as “definite” and fulfilling either criterion as “probable” LVHT. How was “dilated”, “hypertrophic” and “combined” phenotype defined?
It is well known that TDI parameters and measurements are influenced by the type of the echocardiographic machine. Did the authors observe different results when using different machines? Were interobserver variability studies performed regarding registration of the TDI signals? Were there any correlations between heart rate or blood pressure and the parameters measured by TDI?
We miss information about the gender of the included patients, and results of the 2-D and M-mode echocardiographic measurements, like left ventricular wall thickness or enddiastolic diameter. Why were these parameters not included in the calculation of the Cox model? It cannot be excluded that conventional 2-D and M-mode echocardiographic parameters are predictors for prognosis of equal emphasis as TDI parameters. According to which protocol were the follow-up investigations performed? How to explain the discrepancy of patient recruitment starting in January 1999 and the maximal follow-up duration of 132 months? How many thromboembolic events occurred during follow-up? How to explain the threefold increased mortality in the presented cohort compared to the 5.3% mortality/year as observed in adults?
In the two patients with dysmorphic features, which genetic syndrome was diagnosed? Did these two patients also present with skeletal muscle abnormalities? At least in adults, LVHT is frequently associated with neuromuscular disorders. How many of the included 56 patients were seen by a neurologist, and in how many was a neurological disorder detected? Interestingly, in 4 patients LVHT affected the interventricular septum.
Septal LVHT is extremely rare, thus it would be of interest to have more information about these patients. If the authors assume that TDI is influenced by LVHT, why did they choose movement of the basal parts of the ventricle for registration, where no LVHT is located, and not the midventricular or apical parts of the left ventricle, where LVHT is usually located? Which explanation do the authors have for their observation of decreased velocities as assessed by TDI in LVHT? Did the velocities change in patients with undulating phenotype in accordance with improvements in left ventricular systolic function?
In conclusion, before assessing TDI parameters as useful parameters to predict outcome of patients with LVHT, information about other echocardiographic findings and extracardiac comorbidities is necessary.
1. McMahon CJ, Pignatelli RH, Nagueh SF, Lee VV, Vaughn W, Valdes SO, Kovalchin JP, Jefferies JL, Dreyer WJ, Denfield SW, Clunie S, Towbin JA, Eidem BW
Left ventricular noncompaction cardiomyopathy in children: Characterization of clinical status using tissue Doppler-derived indices of left ventricular diastolic relaxation
Heart 2006 Nov 29;ePub
2. Stöllberger C, Winkler-Dworak M, Blazek G, Finsterer J
Prognosis of left ventricular hypertrabeculation/noncompaction is dependent on cardiac and neuromuscular comorbidity
Int J Cardiol 2006; in press
3. Stöllberger C, Keller H, Finsterer J
Disappearance of left ventricular hypertrabeculation/noncompaction after biventricular pacing in a patient with myopathy
J Card Fail 2006; in press
4. Finsterer J, Stöllberger C
Definite, probable , and possible left ventricular hypertrabeculation/noncompcation
Int J Cardiol 2006; in press
5. Kjaergaard J, Korinek J, Belohlavek M, Oh JK, Sogaards Hassager C
Accuracy, reproducibility, and comparability of Doppler tissue imaging by two high-end ultrasound systems
J Am Soc Echocardiogr 2006;19:322-8