Treatment Of Patients With Hypertrophic Cardiomyopathy

To the Editor:

enjoyed reading Ommen and Nishimura’s excellent review article (2000;1(10):393 – 401). The surgeons at Mayo Clinic have excellent results with myomectomy but I can understand why the treatment algorithm favors surgery over non-surgical septal ablation for severely symptomatic patients with outflow tract obstruction.
Most other institutions around the world will be unable to match the surgical outcomes achieved at Mayo Clinic and non-surgical septal ablation may then become the preferred treatment.
I am sure the authors will be aware of the work by Spencer and others from Baylor who have performed electrophysiologic testing before and after non-surgical septal ablation.
They found that patients without inducible arrhythmia prior to their non-surgical ablation therapy had no inducible malignant arrhythmia following the procedure.
Whilst these results do not provide complete reassurance about the late development of malignant arrhythmias, they are encouraging.
Is there any reason to believe that the scar tissue following non-surgical septal ablation is any more likely to be a focus for malignant arrhythmias than the scar tissue following surgical myomectomy?

The authors reply:

   To the Editor:

We appreciate Dr. Hockings thoughtful comments.
His letter highlights an important issue that we believe applies to both surgical myectomy and non-surgical septal ablation.
These procedures are best performed by experienced operators knowledgeable in all aspects of the treatment and pathophysiology.
There is a clear learning curve involved with septal ablation as evidenced by a high rate of procedural morbidity by less experienced centers.
In addition, while the procedural mortality for septal ablation maybe around 3%, there are a significant number of other complications that may occur during the procedure, such as intractable ventricular arrhythmias, VSD, and large myocardial infarctions.
Even in experienced hands, the catheter-based procedure has mortality that is comparable but not necessarily better than that seen with surgical septal myectomy performed by experienced surgeons.
It is unclear whether the neurohumoral response to iatrogenic infarction will result in an increased risk of adverse myocardial remodeling and arrhythmia.
Although the lack of significant post-procedural malignant arrhythmia in the short term follow up is encouraging for septal ablation, we await longer term follow up for this procedure.

STEVE R. OMMEN, MD RICK A. NISHIMURA, MD Division of Cardiovascular Disease Mayo Clinic Rochester, MN 55905 USA

INSTRUCTIONS FOR LETTERS TO THE EDITOR

  Typewritten

 Text up to 200 words
  Please include your full address, telephone number, and fax number or e-mail address     (if you have one).

  You may send us your letter by post, fax, or electronic mail.
  Address letters to: The Editor, Heart Views, Hamad Medical Corporation,
   P.O. Box 3050, Doha, Qatar Fax numbers: (974)4866346 / 4443447 / 4392707
   e-mail:hrtviews@hmc.org.qa