Hypertrophic obstructive cardiomyopathy: about half of patients with Hypertrophic cardiomyopathy (HCM), present an “obstruction to the outflow”, i.e. an obstacle to the exit of blood flow from the left ventricle (LV)
THEobstruction is due to the increased thickness of the septum, that is, from the hypertrophy, present in the area under the aortic valve ("Subaortic"), And from abnormal mitral valve behavior (valve between the atrium and left ventricle), which is larger than normal and moves abnormally, (like a "flag") and obstructs normal flow, that is, the exit of blood from the heart, which often regurgitates into the atrium left ("Mitral regurgitation"). This form of HCM is defined "Obstructive". If the obstruction persists for many years and is not resolved, the clinical course over time is less favorable than in those who do not have obstruction.
At rest it is present in about the 20% of patients with HCM and it is clearly recognized by a "murmur" when the doctor listens to the heart during a visit.
Latent obstructive hypertrophic cardiomyopathy: in another 30% of patients the obstruction occurs only on certain occasions, particularly during effort, or at the end of a demanding effort, or even after a large meal,especially if they exert themselves after the meal.
Some patients with obstructive HCM report no symptoms or reduced capacity for work or exertion. But the majority develop some symptoms during exertion, such as chest tightness, ("angina") and shortness of breath ("dyspnea"), and sometimes even loss of consciousness ("syncope"). These symptoms are usually progressive, meaning they increase over time.
They can improve by taking proper medications. However, patients with severe and persistent symptoms, or with atrial arrhythmias (e.g. atrial fibrillation) or ventricular arrhythmias (e.g. nonsustained ventricular tachycardia), or progressive left atrial dilation, who are unresponsive to medical therapy, are candidates for elimination of obstruction and mitral regurgitation (often associated), with appropriate interventions.