Phonocardiographic changes were studied on 31 cases of Congenital Heart Diseases (CHD) and 9 normal person with innocent murmur with inhalation of Amyl Nitrite and on 10 cases with intravenous administration of Phenylephrine (Neo-Synesin, Kowa).
1. Pulse rate increased with an average of 25 in 30 sec. and 12 in 60 sec. after inhalation of Amyl Nitrite. It decreased with an average of 10 in 1 to 3 min. after administration of Phenylephrine and returned to roughly equal to control in 5 to 8 min..
2. Systemic blood pressure dropped with an average of 24.8 mmHg in 30 sec. and 7.7 mmHg in 60 sec. after inhalation of Amyl Nitrite.
It rised with an average of 24 mmHg in 1 to 3 min. and 9.7 mmHg in 5 to 8 min. after administration of Phenylephrine.
3. Cardiac cycle was shortened of higher grade in diastole than systole after Amyl Nitrite and was prolonged of higher grade in diastole than in systole after Phenylephrine
4. Heart sounds: After inhalation of Amyl Nitrite, amplitude of the first heart sound (I sound) increased and it of the second heart sound (II sound) decreased. IIP/IIA ratio increased. Diminution in amplitude of IIA was more marked compared to IIP. After administration of Phenylephrine, amplitude of both I sound and II sound increased.
5. Pattern of murmurs: After inhalation of Amyl Nitrite, pattern of murmurs showed no marked changes in Atrial Septal Defect (ASD), Tetralogy of Fallot (TOF) and Innocent Murmur (IM) and it changed to plateau type in most Ventricular Septal Defect (VSD), postoperative VSD (op. VSD) and Pulmonary Stenosis (PS). Continuous murmur in typical Patent Duct Arteriosus (PDA) changed typical non-cotinuous murmur. After administration of Phenylephrine, no marked changes were showed in most of CHD, except that component of diastolic murmur in PDA was prolonged.
6. Intensity of systolic murmurs: After inhalation of Amyl Nitrite, intensity of murmurs showed a tendency to be increased in ASD, PS, op. VSD and IM, to be decreased in VSD, PDA and TOF, but in VSD infundibular stenosis or pulmonary hypertension, it was rather increased. After administration of Phenylephrine, it was increased in most cases, and it was more promnenFt in VSD than ASD.
7. Peak of systolic murmurs: after Amyl Nitrite, peak showed no marked changes in ASD, op. VSD and IM and showed a tendency to shift forward in the other diseases. No definite relation with Phenylephrine was observed.
8. Duration ratio of murmurs: After inhalation of Amyl Nitrite, showed a tendency to be shortened in VSD, PDA and TOF and to be increased in ASD and PS. After Phenyleprine in showed a tendency to be prolonged in ASD and to be shortened in VSD.
9. Test of Amyl Nitrite inhalation has been proved to be useful in differentiation of so-called innocent murmurs of op. VSD from systolic murmur of residual VSD.
10. Test of Phenylephrine has been proved to be useful in differentiation PDA from atypical PDA and other diseases.