Exercise Testing Important for HCM Patients

According to a recent study by doctors at Tufts HCM Center in collaboration with colleagues in Italy, exercise testing is an invaluable tool in the assessment of hypertrophic cardiomyopathy patients.

In particular, two types of exercise testing are most valuable for HCM patients:

  • Exercise Echocardiogram:  These tests are valuable in determining whether a patient has obstruction.  It provides a physiological way to measure whether or not a patient has an obstructed left ventricular outflow tract and hence, may potentially be in need of an invasive procedure to treat the obstruction.  According to the article, approximately 1/3 of HCM patients have latent obstruction which may only be seen during or after exercise.  This obstruction is not always apparent from their resting echocardiogram.

and

  • Cardiopulmonary Exercise Testing:  These tests help determine functional capacity and provide a quantifiable indicator of heart failure symptoms.  This test  can identify patients in need of more aggressive treatment options, or who are potentially in need of transplant.  A particularly valuable piece of data from this test is the “VO2 max” score, which is a measure of the maximum rate of oxygen consumption during exercise which reflects the cardiorespiratory fitness level of a person.

*Editor’s note – Exercise testing was particularly informative and important in my own HCM treatment.  It was only after my doctors performed an exercise echo that the extent of my obstruction became apparent.  The symptoms I had been suffering appeared to be out of proportion to what was visualized on my resting echo.  The exercise echo helped my doctors understand the cause of my symptoms which made the next step, in my case a myectomy, much clearer.

You can read my full story here .

 

 

Encouraging Results for MyoKardia HCM Drug

MyoKardia’s stock prices jumped today after their recent Stage II trial of the experimental drug mavacamten (formally known as MYK-461)  demonstrated a statistically significant reduction to left ventricular outflow tract gradients as well as improvement to aerobic capacity in patients with obstructive hypertrophic cardiomyopathy.  

Of the 10 patients who completed the study, 8 saw their gradient reduced to normal levels after 12 weeks on the drug.  The study also showed improvements in both peak oxygen consumption (peak VO2) and New York Heart Association classifications:  7 patients moved up one NYHA class while 2 patients improved by two classes.

The drug seemed to have mild to moderate side effects, though one patient was forced to drop out of the trial due to a recurrence of atrial fibrillation which necessitated discontinuation of mavacamten and a return to anti-arrythmic drugs which had been discontinued due to participation in the trial.

MyoKardia hopes to enroll between 200 and 250 patients in its next phase trial (Explorer HCM) which it plans to begin before the end of 2017.

MyoKardia also plans a clinical trial of mavacamten in non-obstructive HCM patients in the second half of 2017.

For more information on MyoKardia and  recent drugs being developed for HCM read these past blog entries:

MyoKardia HCM Drug Has Success in Cats

End of the Road for Eleclazine and Liberty HCM Study

HCM Drug Trial Advances to Next Round

Drug for Non-Obstructive HCM Moves Along

How to Improve Alcohol Septal Ablation

Alcohol septal ablations (ASA) have been available to HCM patients as a treatment option for the last 20 years.  While the procedure has been the subject of great controversy, some physicians have recently advocated for expanded indications of the ASA procedure.

An editorial in this week’s Journal of the American College of Cardiology from the Netherlands argues that the safety of ASA has been firmly established because mortality rates from ASA have been shown to be comparable to those from septal myectomy.  The Dutch doctors maintain that past concern about ventricular arrhythmia resulting from the scar left by the ablation have not born out.

Making ASA Safer

Now, they argue, the focus should shift from justifying the procedure toward perfecting the procedure.  In particular, the need for additional or repeat procedures must be reduced.  Additional procedures have been necessary due to incomplete resolution of obstruction and/or the need for pacemaker implantation due to heart block, neither of which are a common consequence following myectomy.  1 in 10 patients require a pacemaker following ASA, while only 1 in 25 require one following a myectomy. 1 in 13 patients require a subsequent intervention after ASA (either another ASA or a myectomy), which is 15 times the rate of re-intervention after a myectomy.

The researchers’ suggestions for improvement include:  1) performing ASA only in hypertrophic cardiomyopathy centers of excellence that perform high volumes of the procedure; 2) improving patient selection through the use of a multi-disciplinary team which includes a cardiologist specializing in imaging, a cardiac surgeon, and an interventional cardiologist; 3) using 3D myocardial contrast echocardiography in order to select the best vessels; and 4) use of a small targeted amount of alcohol.

Impact of 3D Myocardial Contrast Echocardiography

In particular, the researchers explain that 3 dimensional myocardial contrast echocardiography (MCE) has proven to be a helpful tool in selection of the appropriate septal perforator.  The use of MCE has resulted in a change in strategy in 15% to 20% of cases:  either by a change in which blood vessel is selected for the alcohol or by prompting the immediate discontinuation of a procedure if the MCE shows that other parts of the heart could be affected.  MCE has also improved the success rate of ASA, while allowing for a more compact scar.

Counterpoint Editorial Advocates National Registry to Quantify Results

An accompanying editorial by Dr. Paul Sorajja from Minneapolis Heart Institute argues that we do not have the data necessary to reconcile the differences in outcome between myectomy and ASA.  In order to better understand the long-term potential and risks of ASA, mandatory reporting should be required.  He points out that this is what is done in other multidisciplinary transcatheter-based therapies, e.g. transcatheter aortic valve replacement for the treatment of aortic stenosis and transcatheter repair of mitral regurgitation with MitraClip.  These procedures require: 1) the use of multidisciplinary teams; 2) participation in a national registry (i.e., The Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy Registry);  and 3) comprehensive reporting of procedural and 1-year outcomes.

Therefore, Dr. Sorajja proposes a national registry created that includes the following information:

  • risk factors for sudden cardiac death
  • LVOT gradients
  • Standardized definitions for procedure success

Guest Blogger – Surgical Myectomy: A Twice in a Lifetime Experience – By Jill Celeste

I have had the joy of being a Registered Nurse for over 40 years. I was born wanting to be a nurse and started bandaging teddy bears at the age of three. By the age of 5, I was creating “medicines” by spinning blades of grass mixed with clover flowers in the front wheel well of an upside down tricycle.

As I got older, I moved on to be a Candy Striper and a Nurse’s Aide, and then I went on to get my degree as a RN, a BSN, and MSN and became a teacher, administrator, and researcher. All of this cannot REALLY prepare you for; “Being on the other side of the bed” which is what happens when a health care professional who is used to caring for patients becomes a patient themselves. Continue reading “Guest Blogger – Surgical Myectomy: A Twice in a Lifetime Experience – By Jill Celeste”