Gallavardin Phenomenon is a physical exam finding in patients that have aortic valve stenosis.
The auscultation at the cardiac apex reveals a murmur which sounds holosystolic and can mimic the murmur of mitral regurgitation.
It's is the result of radiation of the murmur of aortic valve stenosis to the apex rather than coexistent mitral regurgitation.
The finding is sometimes referred to as Gallavardin Dissociation.
In order to determine if the apical murmur is really due to mitral regurgitation or radiation of the murmur of aortic stenosis, dynamic auscultation can also be used.
Handgrip exercises or even transient arterial occlusion increases afterload and will also increase the murmur of the mitral regurgitation while not changing that of aortic stenosis.
The Gallvardian effect is a mid-systolic ejection murmur, heard best over the right second intercostal space, with radiation into the right neck.
Although, high-frequency components may radiate to the apex in calcified aortic valves, and this phenomenon is called the Gallavardin phenomenon.