Q-1 or C-1 interval in the diagnosis of mitral stenosis

Usefulness of the right ventricular systolic to diastolic duration ratio to predict functional capacity and survival in children with pulmonary arterial hypertension

The objective of this study was to investigate the systolic to diastolic duration ratio (S:D ratio) in children with pulmonary arterial hypertension (PAH) and its association with right ventricular (RV) performance, hemodynamics, 6-minute walk test, clinical outcomes, and survival. We reviewed 503 serial echocardiograms in 47 children with PAH (mean pulmonary artery pressure >or=25 mm Hg) and compared the S:D ratio, assessed from Doppler flow of tricuspid valve regurgitation, to that in 47 age-matched controls. We reviewed echocardiograms, catheterization data, 6-minute walk tests, clinical data, lung transplantation, and death and used univariate linear regression models with a maximum likelihood algorithm for parameter estimation to investigate associations between S:D ratio and RV function, hemodynamics, functional capacity, and clinical outcomes. The S:D ratio was significantly higher in patients than in controls (1.38 +/- 0.61 vs 0.72 +/- 0.16, p <0.001). A higher S:D ratio was associated with worse echocardiographic RV fractional area of change, worse catheterization hemodynamics, shorter 6-minute walk distance, and worse clinical outcomes independent of pulmonary resistance or pressures. An increase of 0.1 in the S:D ratio was associated with a 13% increase in yearly risk for lung transplantation or death (hazard ratio 1.13, p <0.001). An S:D ratio 1.00 to 1.40 was associated with a moderate risk and an S:D ratio >1.40 was associated with a high risk of a negative outcome. In conclusion, in children with PAH, an increased S:D ratio is temporally associated with worse RV function, hemodynamics, exercise capability, clinical status, and survival.

The apex impulse in mitral stenosis: graphic explanation of the palpable movements at the cardiac apex

Simultaneously recorded phonocardiograms and apexcardiograms of 39 patients with mitral stenosis (MS) were retrospectively analyzed. A notch on the upstroke of the apexcardiogram coincidental with the first heart sound (S1) occurred in 18 (47%) of the patients. The notch ratio or vertical distance from the onset of the apical impulse to the notch ratio or vertical distance from the onset of the apical impulse to the notch as a percentage of the total upstroke was measured and compared with the mean mitral diastolic gradient obtained at cardiac catheterization. Statistical analysis showed a significant relation (r = 0.61; p less than 0.01) between notch ratio and the mean mitral diastolic gradient. This study reaffirms that the complex palpable movements at the cardiac apex, consisting of a "tap" representing S1 occurring perceptibly after the onset of the apex impulse itself, are a useful diagnostic sign of MS. Furthermore, a graphic measurement of the extent of delay of S1 with respect to the onset of the apical thrust can provide a rough measure of the severity of the valvular obstruction.

Systolic phases of the cardiac cycle in children

The duration of the systolic phases of the cardiac cycle in 390 normal children was determined from high-speed simultaneous recordings of the electrocardiogram, phonocardiogram, apexcardiogram, and carotid pulse. Data were obtained on children 1 mo to 13 years of age and analyzed to define the independent effects of aging and heart rate on the systolic intervals. Electromechanical systole (Q-II) was found to prolong with increasing age in children with the same heart rate. Pre-ejection period was also prolonged in older children and occupied an increased percentage of total systole. The interval from onset of contraction to first sound varied inversely with heart rate and was independent of age. Electromechanical delay and isometric contraction time were directly related to age and independent of rate. Ejection time varied directly with age and inversely with heart rate but occupied a smaller percentage of systole in older children. Alterations in systolic phase duration occurring with maturation reflect the normal functional adaptation of the developing heart. Measurement of these phases can provide useful information relative to cardiac function in children.