There are distinct stages of HCM and treatments will vary according to the stage. Therefore, it is important, according to a recent article in the Netherlands Heart Journal, for patients to seek treatment from teams experienced in the the treatment of HCM. These professionals are able to recognize transitions in the course of the disease as they occur, and then implement necessary changes in treatment.
In this thorough overview of HCM and its treatment, Dr. Iacopo Olivotto and his colleagues in the Netherlands observe that HCM is seen infrequently by community cardiologists (as compared to more common heart conditions like coronary artery disease). Hence, one of the major difficulties in HCM practice has been identification of patients at highest risk.
According to the article, there are four factors which may foreshadow transition to a more advanced stage of HCM.
- reduction of left ventricular function;
- left atrial dilation;
- reduction of maximum wall thickness; and
- onset of atrial fibrillation
These are as follows:
- Stage I – genotype-positive, phenotype-negative individuals. These are individuals (usually identified during family screenings) who carry a gene for the condition, but do not show any thickening of the left ventricle. At this stage, current treatment recommendations include repeated screenings including EKG, echocardiogram and physical examination, but no medication.
- Stage II – classic phenotype. These are individuals who have thickening of the left ventricle, hyperdynamic systolic function, and may also have outflow obstruction. Treatments for this stage include beta-blockers, calcium channel blockers, disopyramide, and ICDs or myectomy, only if and when indicated.
- Stage III – adverse remodeling. In this stage, patients may see a gradual reduction of their left ventricular ejection fraction, progression of diastolic dysfunction and dilation of the left ventricle. Often left ventricular outflow gradients disappear. Treatments in this stage include more standard heart failure therapies such as diuretics, beta blockers, angiotensin converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs) and mineralocorticoid receptor antagonists (MRAs). If atrial fibrillation is present, anti-coagulants are necessary. ICDs may be indicated if there is extensive scarring seen on MRI.
- Stage IV – overt dysfunction. At this stage, the left ventricular ejection fraction may drop below 50%. Diastolic dysfunction is severe, causing heart failure. Medications at this stage include diuretics, beta blockers, angiotensin converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs) and mineralocorticoid receptor antagonists (MRAs). If atrial fibrillation is present, anti-coagulants are necessary. If heart failure becomes severe, referral for heart transplant should be considered before significant elevation of pulmonary pressures, since this can disqualify patient for heart transplant eligibility. In Stage IV, ICDs are indicated.
The article goes on to provide detailed case histories of two individual patients who progressed to Stages III and IV.
Lastly, the article provides some suggestions for future HCM research topics and encourages collaboration between scientists and clinical cardiologists in order to cure the disease.