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Intravascular Stimulation of Autonomics: A Letter from Dr. Michael Scherlag

Letter received by Aviva Lev-Ari, PhD, RN on September 1, 2012

 

Michael Scherlag

To the Editor:

After doing a Google search, I came across your well written article which lacked any references to my research. It would be easy to do a Google search for intravascular stimulation of autonomics to find our work.

The topic of renal denervation is fascinating and holds tremendous promise for the treatment of a plethora of diseases (besides hypertension) which are most likely due to an imbalance of autonomic tone.  Rather than referring to the technique by the misnomer of renal artery denervation, I prefer the name “cardiac sympathetic denervation”.  As I will outline, the ablation of autonomics in the renal artery has more of an effect on the heart than it does on the kidneys.

The possibility that parasympathetic or sympathetic nerves running on blood vessels  could be stimulated or ablated from inside the vasculature was initially demonstrated using basket electrode catheters in a series of experimental studies (1-6) and formally patented in 1999 (7).

Our experiments noted changes in heart rate which have also been reported in SYMPLICITY HTN-1 and SYMPLICITY HTN-2 (8-9).  The SYMPLICITY HTN-2 study demonstrated profound bradycardia in 13% of patients that was treated with atropine.

The intra-procedure effect on heart rate during renal artery denervation documented in the  SYMPLICITY trials is also manifest long term by measuring heart rate variability (10).

Indeed, cardiac effects would be expected with autonomic modulation.  Besides the two example above showing that cardiac sympathetic denervation effects heart rate, there are many more that are just beginning to be reported in the literature.

This article discusses the effect of renal sympathetic denervation on atrial fibrillation.http://www.ncbi.nlm.nih.gov/pubmed/22585944

These articles shows the effects of renal denervation on heart rate. http://www.ncbi.nlm.nih.gov/pubmed/1735574
http://www.ncbi.nlm.nih.gov/pubmed/8777835

A Cleveland Clinic review article states: “Additionally, the resting heart rate was lower and heart rate recovery after exercise improved after the procedure, particularly in patients without diabetes.”
http://www.ccjm.org/content/79/7/501.full

“Brandt reported regression of left ventricular hypertrophy and significantly improved cardiac functional parameters, including increase in ejection fraction and improved diastolic dysfunction, in a study of 46 patients who underwent renal denervation. This findings suggests a potential beneficial effect on cardiac remodeling.” (Brandt MC, Mahfoud F, Reda S, et al. Renal sympathetic denervation reduces left ventricular hypertrophy and improves cardiac function in patients with resistant hypertension. J Am Coll Cardiol 2012; 59:901–909)

“Ukena reported reduction in ventricular tachyarrhythmias in two patients with congestive heart failure who had therapy-resistant electrical storm.” (Ukena C, Bauer A, Mahfoud F, et al. Renal sympathetic denervation for treatment of electrical storm: first-in man experience. Clin Res Cardiol 2012; 101:63–67)

The most recent data from Europe shows the following effects on heart failure: http://www.eurekalert.org/pub_releases/2012-08/esoc-rdg082712.php
http://www.theheart.org/article/1364267.do

Nearly ten examples of the effects of “CARDIAC SYMPATHETIC DENERVATION” and what are the effects on the kidney?  No change in GFR.  No change in creatinine.  My question to you is why does Dr. Esler refuse to cite our work?  Clearly, we were the first to stimulate/ablate autonomic nerves effecting the heart from the intravascular space.  If you doubt that, please see the patent.  Maybe, it is his conflict of interest with funding and consulting fees coming from Ardian/Medtronic.  I have sent emails and requests to Dr. Esler and other Symplicity investigators to cite our work, yet they refuse.

I do not use the term plagiarism lightly.  It is my hope that you will ask Dr. Esler and his cohort of Symplicity investigators why they refuse to cite our work.

I would also, respectively, ask that you cite our work.

Sincerely,

Michael Scherlag, MD
Interventional Cardiologist
Oklahoma Heart Hospital

References:
1. Schauerte P, Scherlag BJ, Scherlag MA, Goli S, Jackman WM, Lazzara R. Transvenous parasympathetic cardiac nerve stimulation: an approach for stable sinus rate control. J Electrophysiol. 1999 Nov;10(11):1517-24.

2. Schauerte P, Scherlag BJ, Scherlag MA, Goli S, Jackman WM, Lazzara R. Ventricular rate control during atrial fibrillation by cardiac parasympathetic nerve stimulation: a transvenous approach. J Am Coll Cardiol. 1999 Dec;34(7):2043-50.

3. Schauerte P, Scherlag BJ, Pitha J, Scherlag MA, Reynolds D, Lazzara R, Jackman WM. Catheter ablation of cardiac autonomic nerves for prevention of vagal atrial fibrillation. Circulation. 2000 Nov 28;102(22):2774-80.

4. Scherlag MA, Scherlag BJ, Yamanashi W, Schauerte P, Goli S, Jackman WM, Reynolds D, Lazzara R. Endovascular neural stimulation via a novel basket electrode catheter: comparison of electrode configurations. J Interv Card Electrophysiol. 2000 Apr;4(1):219-24.

5. Scherlag BJ, Yamanashi WS, Schauerte P, Scherlag M, Sun YX, Hou Y, Jackman WM, Lazzara R. Endovascular stimulation within the left pulmonary artery to induce slowing of heart rate and paroxysmal atrial fibrillation. Cardiovasc Res. 2002 May; 54(2):470-5.

6. Hasdemir C, Scherlag BJ, Yamanashi WS, Lazzara R, Jackman WM. Endovascular stimulation of autonomic neural elements in the superior vena cava using a flexible loop catheter. Jpn Heart J. 2003 May;44(3):417-27.

7. Webster W Jr, Scherlag BJ, Scherlag MA, Schauerte P. Method and apparatus for   transvascular treatment of tachycardia and fibrillation. US Patent 6,292,695. Filed June 17, 1999.

8. Krum H, Schlaich M, Whitbourn R, Sobotka PA, Sadowski J, Bartus K, Kapelak B, Walton A, Sievert H, Thambar S, Abraham WT, Esler M. Catheter-based renal sympathetic denervation for resistant hypertension: a multicentre safety and proof-of-principle cohort study. Lancet. 2009;373(9671):1275-1281.

9. Symplicity HTN-2 Investigators. Renal sympathetic denervation in patients with treatment-resistant hypertension (The Symplicity HTN-2 Trial): a randomised controlled trial. Lancet. 2010;376:1903-1909.

10. Frank Himmel MD, Joachim Weil MD, Michael Reppel MD, Kai Mortensen MD, Klaas Franzen, Leidinger Ansgar MD, Heribert Schunkert MD, Frank Bode MD.  Improved Heart Rate Dynamics in Patients Undergoing Percutaneous Renal Denervation. Letter to the Editor. JCH. 31 MAY 2012.1751-7176.

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