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Is the new professionalism and ACP's new ethics really just about following guidelines?

The Charter ( Medical Professionalism in the New Millennium.A Physician's Charter) did not deal with just the important relationship of ...

Sunday, April 23, 2017

"Para Hisian Pacing" as well as selective Bundle of His pacing may bring about a hyper response

I have written before about a sub group of Cardiac resynchronization patients (CRT)   who have a hyper response with marked improvement in indices of cardiac   function, e.g. ejection fraction and end diastolic volume.

Such responses have been reported with Biventricular pacing  (Bi-V) and  His Bundle Pacing ( HBP). There are two forms or types of HBP: 1) pure HBP also known as selective and 2) Para Hisian pacing also known as non  selective HBP.

The QRS is normalized with selective HBP while in nonselective although the widened QRS duration is significant reduced it may not be restored to the pre  bundle branch block  configuration. There is both activation of the His Bundle fibers and adjacent ventricular septal muscle giving a fused or fusion ventricular activation pattern. 

According to Lida et al writing in the December 2016 Journal of Arrhythmia (1) "there seems to be no significant clinical difference between selective HBP and non selective HBP because both do not alter physiological impulse conduction and possibly maintain rapid and synchronous LV ( left ventricular) activation "

A similar case report was published by Ajijola et al  from UCLA in 2015 (2)

His Bundle pacing seems to gaining momentum both as an alternative to right ventricular pacing and as a method of cardiac resynchronization.

1)Lida, Y et al Successful resynchronization by permanent His-bundle pacing in patient with pacing -induced cardiomyopathy' J Arrhythmia , 2016 Dec. 32(6), 499-501

2)Ajijola,O et al Hyper-response to cardiac resynchronization with permanent His bundle pacing:Is parahisian pacing sufficient? Heart Rhythm Society, open access article http://dx'doi.org/19.10.hrcr.2015.05.006

Addendum:  5/26/2017  Several papers presented at the May 2017 meeting of the Heart Rhythm Society indicated that His Bundle pacing is ready for prime time.  See Dr. John Mandrola's  article on Medscape entitled " His Bundle pacing hits the mainstream at HRS 2017".
On a personal note-It is now almost two years since I was implanted with a Pacemaker with Bundle of His pacing before the practice became more mainstream. I had developed a left bundle branch block and an exercise induced second degree heart block. The LBBB had  markedly decreased my exercise tolerance. My LBBB was "fixed" and after getting over a few complications of the procedure my exercise tolerance was back to my pre LBBB level .

Friday, April 14, 2017

If peak load is the determing parameter runners should have more osteoarthritis

Perhaps it seems counter intuitive that runners do not have a higher incidence of knee osteoarthritis or so the preponderance of epidemiologic data contents.After all the peak load of the articular cartilages in running is much higher than in walking or so the kinesiologists tell us and would not the cumulative higher peak load after many miles of running wear out and maybe chew up the articular cartilages.

Or maybe the explanation does not lie in the peak load.

 Ross H Miller from the Department of Kinesiology at the University of Maryland offers an alternative view (1) and an alternative analysis of the relevant forces conspiring to "wear out" the knees.

He suggested that peak load is not the relevant variable but rather it is the "average load per distance traveled"  which is said to be surprisingly low and purportedly similar to walking.

Ross also discussed the notion of cartilage conditioning .Knee cartilage glycosaminoglycan content( which affects lubrication and shock absorption ) has been  shown in one study to be greater in recreational runners and even greater in high volume runners.

"... a man hears what he wants to hear and disregards the rest" Paul Simon.The Boxer

1) Miller, RH "Joint loading in runners does not initiate knee osteoarthritis" Exerc Sports Sci  Rev 45(2), 87-95,4 2017