Differential Diagnosis
- Single most likely diagnosis
- Hypertrophic Cardiomyopathy (HCM): The presence of a mild concentric left ventricular hypertrophy, a resting LVOT gradient of 7 mmHg, and an increase in the LVOT gradient to 19 mmHg with Valsalva maneuver are suggestive of HCM. The symptoms of cough followed by syncope could be related to the obstructive nature of HCM, especially if the cough increases intrathoracic pressure, thereby increasing the outflow tract obstruction and potentially leading to a decrease in cardiac output and subsequent syncope.
- Other Likely diagnoses
- Aortic Stenosis: Although the LVOT gradients are not as high as typically seen in severe aortic stenosis, mild aortic stenosis could still be a consideration, especially if the patient has a bicuspid aortic valve or other congenital heart defects. The symptoms could be consistent with exertional syncope, a classic symptom of aortic stenosis.
- Left Ventricular Outflow Tract Obstruction (LVOTO) due to other causes: Other conditions such as subvalvular or supravalvular aortic stenosis could also cause similar symptoms and findings.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Aortic Dissection: Although less likely given the information, aortic dissection is a life-threatening condition that could present with syncope and could potentially cause an increase in LVOT gradient due to involvement of the aortic root. It's crucial to consider this diagnosis, especially if there's a history of hypertension or aortic disease.
- Pulmonary Embolism: A large pulmonary embolism could lead to syncope due to a sudden decrease in cardiac output. While not directly related to the LVOT gradient, it's a critical diagnosis to consider in the context of syncope.
- Rare diagnoses
- Cardiac Sarcoidosis: This condition can lead to left ventricular hypertrophy and could potentially cause obstructive symptoms similar to HCM, although it would be less likely given the specific findings.
- Fabry Disease: A genetic disorder that can lead to left ventricular hypertrophy, it might present with similar echocardiographic findings, though it's much rarer and would typically be associated with other systemic symptoms.