Amyl nitrite test using double microphones for differentiation of systolic murmurs in the elderly.

Abstract

The effects of amyl nitrite on systolic murmurs and hemodynamic alterations in the elderly have been studied with amyl nitrite test using 2 phonocardiographic amplifier channels and 2 microphones of the same frequency response. From the simultaneous recording at the aortic and apical region, the alteration of the amplitude of systolic murmurs in both areas after inhalation of amyl nitrite was checked. In Germany, we named this method with 2 microphones as Doppel Amyl-nitrit Versuch.Mechanocardiographically the time intervals such as HR, Q-I, Q-IIi, ET, ETi, PEPi were checked. The following observations were made: Alterations of systolic heart murmurs were divided in 4 different groups, namely, (1) increased murmurs in both regions, the apex and base (group I), (2) decreased murmurs in both areas (group II), (3) increased murmurs at aortic area and decreased murmurs at the apex (group III), (4) others: i.e. increased murmurs only at the apex, and decreased murmurs only at the apex or base (group IV).The results support the opinion that the effects of amyl nitrite in the elderly is not as conspicuous as in children. Amyl nitrite test using double microphones may be useful to differentiate the origin of some murmurs as the Gallavardin phenomenon.The Gallavardin phenomenon is the more common in the older patients. Furthermore, apical murmurs may also be conducted often to the base of the heart, especially when the left ventricle and ascending aorta are dilated (anti-Gallavardin mechanism). Under some conditions the systolic murmur of mitral incompetence may have its maximum intensity at fourth or third left ICS.