Evaluation of Left Ventricular Contractile State in Childhood

Left ventricular contractile state was evaluated in 20 children ages 3 to 11 years with normal left hearts and in 15 children ages 2 to 16 years with a left ventricular pressure overload. All patients were studied during diagnostic cardiac catheterization with catheter-tip micromanometry. Pressure-velocity curves were obtained during isovolumic systole by plotting (dp/dt)/28 P versus developed or total pressure (P). Computer analysis of five cardiac cycles was used to yield one composite pressure-velocity curve for each patient with both linear and second-degree polynomial curve analysis. The developed pressure method yielded higher values for the calculated V max index, (dp/dt)/28 P at zero P than the total-pressure method for all patients. Normal standards were defined for both methods. The V max index calculated with total pressure as well as peak (dp/dt)/28 P was significantly less than normal for the hypertrophy group. The V max index calculated with developed pressure was not significantly different from normal for the entire hypertrophy group, but four of the 15 patients showed a depression of contractile state defined as a value for the V max index less than 2 sd of normal. These results indicate the potential importance of preoperative and postoperative estimation of contractile state in patients with a left ventricular pressure overload in evaluation of possible irreversible alterations of contractility that may accompany myocardial hypertrophy.