Hemodynamic Response to Exercise in Isolated Pulmonic Stenosis

Abstract

THE value of observations made during exercise in assessing the severity of isolated pulmonic stenosis has been recognized previously.1-4 Elowever, the small number of patients studied, the coincident occurrence of right-to-left shunting, and the paucity of comparable data in normal subjects have made for difficulties in interpretation. As a more precise assessment of the severity of pulmonic stenosis became necessary with the development of surgical technics for correction, exercise response was emphasized by Brock.5 The need for evaluating the rise of right ventricular systolic pressure during exercise in the selectioin of patients for surgery was stressed, and Johnsoin(" pointed outt its importance in the appraisal of the results of valvotomy.The ptirpose of this report is to present observations on the circulatory response to) exercise in a selected group of adult subjects with isolated pulmonic stenosis by uise of a technic f.or simultaneous measurement of pulinonary arterial and right ventricular pressures, and the Fick principle method for determination of cardiac output. Materials and MethodsAll patients studied were subjected to careful examination to exclude congenital cardiac anomalies other than pulmonic stenosis with intact ventricular septum. In addition to clinical examination, this included ani electrocardiogram, chest teleroentgenogram, and right heart catheterization. Particular attention was directed toward exclusion of subjects in whom intracardiac shunting mechanisms existed at rest or during exercise.

Ventilation and haemodynamics in heart disease.

“…10) Group V: Pulmonary Stenosis (27). The heemodynamic findings (Table II) reported from this laboratory (Johnson, 1962) and elsewhere (Joos et al, 1954;Lewis et al, 1964).…”

“…Here the effects of low cardiac output can therefore be seen in a purer form than in the other groups. Previous studies in such patients have yielded conflicting results: Sloman and Gandevia (1964) found a normal ventilatory response during upright exercise, while Lewis et al (1964) found an exaggerated ventilatory response during supine exercise. Our results indicate that about one-third of the patients with pulmonary stenosis hyperventilate during both supine and upright (Gazetopoulos et al, 1966) exercise.…”

Functional and haemodynamic assessment of mild-to-moderate pulmonary valve stenosis at rest and during exercise

“…Consequently, exercise capacity is reduced due to an inability to increase stroke volume with the increase in heart rate being the sole contributor to an increase in cardiac output 5 6. Conversely, the natural evolution of mild PV stenosis is considered to be benign without progression of the valve gradient after adolescence and no deaths are observed during an 8-year follow-up period 3 7.…”

Balloon Pulmonary Valvuloplasty

“…Some controversy exists with regard to indications for dilation in patients with moderate pulmonary stenosis and gradients in the range of 35 to 50 mmHg. Though these patients are likely to do very well for years, they demonstrate abnormally low maximal cardiac output, increased oxygen extraction, abnormal ventilatory responses, as well as marked increases in right ventricular pressures with exercise [17]. It is reasonable to consider valvuloplasty in such patients, though more long-term follow up will be required to clarify the best approach for this group.…”