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Hypertrophic Cardiomyopathy in Childhood: Disease Natural History, Impact of Obstruction, and Its Influence on Survival

EJ Hickey, BW Mc Crindle, SH Larsen... - The Annals of Thoracic ..., 2012 - Elsevier Background We investigated the natural history, outcomes of myectomy, and impact on survival of obstructive hypertrophic cardiomyopathy (HCM) in childhood. Methods All 120 children diagnosed with HCM between 1971 and 2006 were studied. Available ...

Fig 3. (A) Outcomes of surgical myectomy on progression of peak instantaneous left ventricular outflow tract gradient over time. Regression equations (adjusted for repeated measures) have been solved for the following groups of children: (1) nonobstructive hypertrophic cardiomyopathy (HCM); (2) preoperative in those who underwent myectomy; or (3) postoperative in those who underwent myectomy. Children with nonobstructive HCM showed a progressive fall in peak gradients over time (p = 0.04). In contrast, those who underwent myectomy had significantly higher peak gradients (p < 0.001) and exhibited a time-related increase in these gradients (p = 0.04) preoperatively. Surgical myectomy was effective in both significantly reducing the peak gradient (mean, 57 mm Hg reduction; 95% CI, 25.3 to 87.8; p < 0.01) and the gradient continued to reduce thereafter at a rate comparable with nonsurgically managed children. For each plot, time transformations were explored to optimize log likelihood model fit ( no surgery = square transformation and preoperative = log transformation). (B) Outcomes of surgical myectomy on maximal interventricular septum zscore thickness. Regression equations (adjusted for repeated measures) have been solved for the following groups of children: (1) nonsurgically managed; (2) preoperative in those who underwent myectomy; or (3) postoperative in those who underwent myectomy. Children who do not undergo myectomy did not show a significant change in septal z score over time (p = 0.76). In contrast, those who underwent myectomy had higher septal z scores at the time of diagnosis (p = 0.04) and exhibited a time-related increase in septal hypertrophy (p < 0.001) preoperatively. Surgical myectomy then reduced the septal thickness to values comparable with nonsurgically managed children and septal z scores did not significantly alter thereafter. For each plot, time transformations were explored to optimize log likelihood model fit ( preoperative = square transformation). Lines represent parametric regression equations ( best-fit curves) adjusted for repeated measures.