Causes of dynamic LVOT obstruction

Causes of dynamic LVOT obstruction

Causes of dynamic LVOT obstruction: Hypertrophic cardiomyopathy is the most important cause of dynamic LVOT obstruction (left ventricular outflow tract obstruction). In transposition of great arteries (TGA) with intact interventricular septum LVOT obstruction due to systolic anterior motion of mitral valve (SAM) is possible. SAM can also occur transiently following surgery for aortic stenosis and mitral valve repair and cause LVOT obstruction. Dynamic LVOT obstruction is also described as a rare association with myocardial infarction possibly due to SAM. Dobutamine can worsen the LVOT obstruction in this situation.

Ji Hyun Yang and colleagues reported a case of severe LVOT obstruction after treatment with catecholamine [1]. Hypovolemia accompanied by catecholamine treatment may cause LVOT obstruction due to systolic anterior movement of mitral valve. Prompt recognition with correction of hypovolemia and withdrawal of catecholamine therapy is the solution to this problem.

Similar to catecholamine therapy, pheochromocytoma is a rare reversible cause of dynamic LVOT obstruction. B Gallet and associates reported a case with LVOT gradient 120 mm Hg on Doppler echocardiography [2]. The gradient disappeared completely after removal of pheochromocytoma.

References

1. Ji Hyun Yang, Seung Woo Park, Jeong Hoon Yang, Sung Won Cho, Hyo Song Kim, Kyoung A Choi, Ho Joong Kim. Dynamic Left Ventricular Outflow Tract Obstruction Without Basal Septal Hypertrophy, Caused by Catecholamine Therapy and Volume Depletion. Korean J Intern Med. 2008 Jun;23(2):106-9.
2. B Gallet, H Quintard, J Fruchaud, M Hiltgen. Dynamic Left Ventricular Obstruction Associated With a pheochromocytoma Reversible After Tumor Ablation. Arch Mal Coeur Vaiss. 2001 Nov;94(11):1195-8.