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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 Vmax index, (dp/dt)/28 P at zero P than the total-pressure method for all patients. Normal standards were defined for both methods. The Vmax index calculated with total pressure as well as peak (dp/dt)/28 P was significantly less than normal for the hypertrophy group. The Vmax 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 Vmax 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.

Evaluation of Left Ventricular Contractile State in Childhood