Tuesday, September 29, 2015

New and better ways to distinguish "athlete's heart" from abnormal heart enlargement

It has been long recognized that athletes may have larger hearts and changes on the EKG that are difficult to distinguish from abnormal findings such as those seen in an abnormally enlarged and thickened  left ventricle with hypertrophic muscles as is seen in long standanding hypertension.

In fact athletes have enlarged heart muscle as well and cardiologists have attempted to provided some wall thickness values above which it is thought to be too big to indicate the physiologic increases in muscle and chamber size of the athlete and represent pathological and maladaptive muscle growth. A distinction  based on various  EKG criteria have never been that reliable.

In addition, all athletic activity does not seem to bring out the same type of physiological adaptive changes. A distinction is typically made between endurance athletes and strength athletes, recognizing that some athletes do both endurance and strength training.

Generally endurance athletes increased cardiac output under conditions of  reduced peripheral resistance while strength trained athletes increased cardiac output against increased peripheral resistance. It would not be unexpected that these difference would be reflected in the heart's adaption

The stylized facts are that  the endurance athletes have increased wall thickness  as do the strength folks but endurance athletes have larger chambers . e.g left atrial size and left ventricular diastolic diameters. The usual definition of the upper limit of normal for the left atrium is often said to be 35ml while one  study of endurance athletes has shown value of 37.7 ml.The left  ventricular wall is sometimes greater than 13 mm ( in one study of elite endurance athletes 13% were greater than 13 but none above 15 mm.  About 1/3 of elite endurance athletes have LV cavity end diastolic greater than 60 ml. whereas  upper  normal is typically consisted 55 ml Typically endurance  athletes are said to have eccentric hypertrophy while endurance athletes have concentric but that concept has  been challenged.

At least one study reported that endurance athletes had indicators of  better diastolic function that do strength trained athletes. (Vinereanu,D, Clin Sci 2002).However, overall the data are conflicting as to whether endurance exercise improves diastolic filling apart from  heart rate changes and
 as to whether any diastolic function improvement persists in senior athletes to significantly mitigate the seemingly universal age related increases in myocardial stiffness. ( Perhaps another example of the Woody Allen physiological maxim ,paraphrased when you get old everything  that should be soft gets hard and everything that should be hard gets soft.)

In any event the athletes hearts seems to work quite well particularity when compared with the enlarged heart s that can results from hypertension both in terms of pumping  the blood during systole but also  in rapidly refilling the ventricular chamber in diastole preparatory for the next ejection

Athletes hearts  pump more effectively  blood during systole This is   usually expressed as as EF, value ( ejection fraction) which is  generally greater in endurance athletes than in  normals but the range overlaps. .But also the athlete's  ventricles  fill faster in the relation phase of the left ventricle , i.e. diastole so their enhanced cardiac output results from more filling  and more ejection giving them higher stroke volumes.

Using various indicators of diastolic function ( such as the early phase of filling versus the later phase of filling (an e/a ratio being one such measure) it has been  clearly demonstrated that left ventricular filing is normal or supra normal in the endurance  athletes with increased wall thickness while the opposite occur to varying degrees in hypertensive heart disease and other causes of LVH such as aortic stenosis and hypertrophic cardiomyopathy .

Newer echo techniques have provided even more evidence of a distinction   between the enhanced  cardiac function of the endurance trained athletes and those with hypertensive heart disease and to aid in the differential diagnosis of hypertrophic cardiomyopathy.

In the last ten years a technique referred to as deformation imaging ( which can be subdivided into 1)TDI and 2)speckle-tracing 2D strain imaging  has provide a new way to elucidate cardiac physiology. The techniques can distinguish between active and passive myocardial segment motion.

In echo speak "strain" mean deformation, unlike the  everyone day English language meaning of stretching and these techniques measure strain and strain rate.Strain is considered the fractional change in length of a myocardial segment and can be expressed as a percentage.Ultra sound images contain natural acoustic markers, called speckles, which can be tracking as muscle segments move during contraction and relaxation and actively contracting muscles segment can be distinguished from areas moving poorly. 

Speckle tracing studies have shown that the ventricular hypertrophy as in  hypertension is associated with decrease strain ,that is less deformation, which is functionally disadvantageous while the hypertrophy of endurance athletes does not differ appreciably from normal controls and is not associated with  functional impairment.In other words this is  an advantageous remodeling.

A similar distinction between pathological left ventricular hypertrophy and  physiologic athletic hypertrophy  has been made using MRIs of the heart. ( Peterson SE, 2005 , J Cardiovas Mag Reason 2005:7,(3) 551. Speckle tracing is much less expensive .

For the most part newer testing techniques have done away with concerns about exercise causing the heart to enlarge in a deleterious physiological way with the interesting possible exception of  harmful changes or remodeling of the right ventricle. Several authors have argued and provided some evidence that prolonged endurance type exercise can bring about a condition similar to an inherited disease called arrhythmogenic  right ventricular hypertrophy (ARRV), a topic I wrote about before see here.

addendum: added 10/1/15 5:46 PM.  Here is more on the differences between strength athletes and endurance athletes. Rowers were compared with Long distance runners and the authors fond  that the runners had larger left ventricular volumes,lower and in the normal range for ventricular mass and a tendency to less thickened left ventricular walls.  (Wasfy,M Endurance exercise-induced cardiac remodeling: Not all Sports are created equal,Journal of the American society of echocardiography, 2015,Sept 9


Thursday, September 03, 2015

George Soros's Open Society Institute and American Board of Internal Medicine Foundation programs,strange bedfellows or birds of a feather?

Medical Professionalism for the new Millennium; A Physician's Charter was published in 2002 both  in the Annals of Internal Medicine and in the Lancet reflecting an international authorship. In 2003, George Soros's Open Society Institute founded a think tank, advocacy organization called Institute on Medicine as a Profession. (IMAP) with a 7.5 million dollar grant.

Later two grants ($350,000 in 2003 and $ 60,000 in 2008) was  given to IMAP by the ABIMF.ABIMF is chiefly funded by the ABIM and has a common leadership roster.In turn ABIM makes its money by testing internists and managing their Maintenance of Certification (MOC) program,a program that has generated a firestorm of protests from practicing internists and a serious effort to establish a rival means of maintenance of certification.

What is the ACP-ABIM(F) version of medical professionalism. Among other features, this "charter" calls for physicians to be "stewards of society's medical resources" and to work for social justice. It speaks of an obligation not only to the patient but to society as least in the sense of conservation of these allegedly common resources and to work for a just distribution of these resources.

The Charter was not cut from whole cloth, neither was it a tailored answer to the alleged problems that were claimed to be causing physicians angst  in the new millennium.Rather it was another manifestation or application of the new Bioethics about which Pope Benedict XVI had this to say in his 2010 address to the Pontifical Academy for Life:

"Under traditional medical ethics the guiding principle is 'do no harm". But contemporary bioethics abandons this in an effort to find the utilitarian goal of the greatest good for the greatest number Under these principles preserving the life of the human patient is not considered paramount."

Wait. what  does the charter have to say about greatest good for the greatest number? Explicitly it said nothing but advocating social justice.

Social Justice is a loose , vague and indeterminate term, which although it has a useful rhetorical value   might puzzle physicians as to how they might actually work for the nebulous social justice in their everyday practices. The ABIMF in its publications and on its website made it explicit -follow the guidelines. In that way they claim  resources would be wisely distributed and fairly  thus furthering social justice. Here we get the greatest good for the greatest number in the collective. The collective may just be the HMO or ACO or possibly all members of society.So while the Charter seems on the surface to be medical ethical Principlism , a la Beaumont and Childress, underneath there is a strong utilitarian initiative .

ABIMF's mission appears to be to further this brand of medical professionalism and to
champion the "Choosing Wisely" initiative.

 IMAP describes its mission in the following way:
Their vision of medical professionalism  embodies 4 values;

1) altruism that is a unwavering commitment to the patient.
2)Physician Self regulation
3)Maintenance of technical competence-a commitment to life long learning
4)Civic engagement "Physicians should enlarge their scope of concerns from the welfare of the individual patient to a concern for the welfare of all patients" ( my underlining)

This parallels the outline of the Charter which continues to speak of duty to the patient but an additional obligation was grafted on to that traditional prime directive namely to conserve resources and work for an efficient and fair distribution of resources.Numbers 1,2, and 3 add nothing to traditional medical ethics but number 4 is another matter.

So IMAP more or less recapitulates the Charter blending the traditional mom and apple pie medical ethics with a new obligation to work somehow for all patients.It should be no mystery why ABIMF might share some of its resources with another advocacy group with similar if not identical goals. My question is why does Soros wish to promote the new professionalism i.e. the Charter ?

So here it is- the physician's goal should not just be the welfare of her patient but rather the welfare of everyone.And the best way she could accomplish that goal is to follow guidelines which will provide the best band for the buck (efficient parsimonious care) .And one way to say money is  to limit care to the elderly which is being sold as improving the quality of life in folks in their twilight days and months.

One of the leaders in the effort to limit care to the elderly , Dr.Joanne Lynn,perhaps said more that she intended when she said:"Not only the right thing to do, it makes good business sense".

Good business sense, is that what Choosing Wisely is all about?

Thursday, August 06, 2015

Still more data linking endurance exercise and atrial fibrillation

A number of  studies have shown a relationship between long time endurance exercise and increased  risk of atrial arrhythmias. and there is a growing consensus that this is a causal relationship. As a long time marathoner I don't welcome the news but I cannot no longer ignore it and have to worry about it. 

One of Bradford Hill's classic  criteria for assessing if a relationship between variables is causal is the dose response principle also referred to as biological gradient. This simply means that a larger dose or exposure should lead to a greater incidence of the effects.Myrstar and co authors  have published a study demonstrating a dose response relationship between years of endurance type activity and risk of atrial fibrillation and atrial flutter. In this article Myrstad and co-authors reported an odds ratio of development of atrial fibrillation of 1.16 per ten years of endurance exercise. (confidence interval 1.06--1.29).

 In another study from Norway the same lead author reported in regard to  a cohort study  of 2626 long time cross-country skiers and 2326 people from the general population. He found a prevalence of 12.3%  of self reported atrial fibrillation (AF) in the skiers versus 5% in the non-skiers. Of those, 64% continued to engage in regular endurance exercise after the onset of AF.Interestingly some 1/3 of AF patients did not use oral anticoagulants even though they had a CHA2DS-VASc scored of greater than or equal to 2,a score that current conventional medical wisdom believes anti coagulation is needed to decrease stroke risk.

 To get some approximation of context consider the ATRIA study (Go,A, et al, JAMA 2001:285:2370) which reported a prevalence of 0.1% in those younger than 60 years,3.8 % age 60 and older, and 9 % age 90 and older More extensive data can be found here in the discussion of a pooled analysis of five randomized clinical trials in which the relative risk of a fib increased 1.4 by decade ( C.I. 1.1 to 1.8). Some older runners would like to take those factoids to suggest that getting old is even more risky than running.

 An enlarged left atrium  has thought to be the  likely link between atrial fibrillation and hypertension.Some long term endurance athletes have been demonstrated to have larger left atria and while it can be considered a "physiological" adaption to increased exercise and periods of increased cardiac output the increased surface per se  may predispose to atrial rhythm mischief.Is the enlarged athletes' left atrium less pathological than that of the long term hypertensive patient?

Most of this is a "dog bites man" or duhh story but I continue to be impressed with how easily one can effortlessly find medical articles even in Journals that are not that widely read. The second article mentioned above was first published  in the official journal of the German Cardiac Society, one that I do not typically read. The ease with which you can follow current journal articles on a number of topics of your choosing on the free app QxMD is amazing particularly for someone who grew up wrestling the unwieldy Index Medicus tomes and wandering the medical library book stacks to find the volume of interest missing.You can easily learn more in an hour with that app and your tablet than you could in all day at the medical library.

addendum:10/1/15 some editorial flourishes made.

Tuesday, July 21, 2015

Born to run (slowly) and to loaf-The Leiberman hypothesis?

Harvard Professor David E. Leiberman  has taken Theodosius Dobzhansky's maxim to heart; "Nothing in biology makes sense except in the light of evolution."

Leiberman,also known as the barefoot professor for his interest and advocacy of barefoot running ,expounded his thesis along with co author Dennis Bramble in a 2004 article in Nature entitled " Endurance running and the evolution of the genus homo."

Quoting from the above article ;" The fossil evidence of these features [features that facilitate endurance running] suggests that endurance running is a derived capability of the genus Homo, originating about 2 million years and may have been instrumental in the evolution of he human body form."

Leiberman's theory suggests that Homo evolved the ability to run long distances and hunt and forage in the heat before the human brain grew and humans got smart enough to  rule the roost .

The creature than evolved  could be described as a fur less,short toed,sweaty bipedal endurance athlete who was typically at the edge of negative calorie balance and who tended to loaf and rest whenever he could to conserve energy as food was scarce and difficult to obtain.These were the hunter gatherers whose survival depended on their ability to track and hunt animals over long distances in the climates of the African savannas as well as to dig around and find what they could to eat. That stylized story is that is how our ancestors lived as recently as some 600 generations ago, according to some estimates.

As the pressing need to work very hard physically became less and less necessary for more and more people the evolved human's drive to rest and conserve energy persisted and when not countered by lots of exercise obesity and the modern maladies such as  arterial diseases and type 2 diabetes went from rare to increasingly common.

It is an appealing story,one that resonates with those among us who like to do endurance type exercise. This includes Leiberman .  Much of it seems to make sense and is rich in physiologic insights, but is it all  just an "as if story"?

Hans Vaihinger is known as the philosopher of "as if". His view was that one should not ask if a theory or belief was true in some deep probably unknowable objective sense but rather is it useful to act as if the theory were true. ( I think Milton Freidman spoke of economic models or theory is that way, that is are they useful.) From reading descriptions of Vaihinger's work, I think it seems to him maybe most stories are "as if stories".

Leiberman writes and speaks well in an entertaining way and regales us with mechanisms  such why tighter ( rather than more lax) Achilles tendon enables running and why longer toes are a detriment to running  and how sweating works much better as a heat dissipation mechanism than panting.

Tuesday, July 14, 2015

Bob Wachter's defense of ABIM's shenanigans and Mel Brooks

Dr. Bob Wachter,former chair of the ABIM, has spoken out in defense of ABIM and , of course, of himself.

Several medical bloggers have offered their critique of his comments including Michel Accad,  ,Walter Bond. and Dr RW..In my opinion all make  some good points with which I agree.

But I think Med Brooks' comments  may be the most appropriate.

Friday, July 10, 2015

Can Dr. Cassel and her collaborators at the National Quality Forum repeal Goodhart's Law?

In the December 4, 2014 issue of the NEJM, Dr. Chistine K.Cassel et al expound on performance measures.She freely admits there have been some problems but also apparently some successes.It is just a matter of learning from the mistakes and  leveraging the successes. We just have to work harder and be smarter. "Getting More Performance from Performance Measurements" Cassel, CK et al , NEJM 371,23 2014)

She offers her explanation of  why the notorious "four hour pneumonia rule" did not work out well. That particular clinical situation was "not the right place to intervene". .."There was too much clinical variability for the measure to help physicians on exactly the right course of action." True enough but that was not the reason.

The underlying insight is found in Goodhart's Law which states that when a measure becomes a target it loses its value as a measure.A more basic insight is that people respond to incentives. When folks are graded, or rewarded or punished based on some measure they will find ways to achieve that target and if better care results fine but there is not reason to think apriori   that it will. Teachers will teach to the tests and students will study for the test regardless of how well or how badly the test reflects the students mastery of the subject.

Goodhart wrote about his "law " in 1975 and in 1976 Donald Campbell wrote in regard to education and testing :

"achievement tests may well be valuable indicators of general school achievement under conditions of normal teaching aimed at general competence. But when test scores become the goal of the teaching process, they both lose their value as indicators of educational status and distort the educational process in undesirable ways.

It is tempting to substitute medicare care for  the teaching process and we get "But when quality measures become the goal of the medical care process , they both loose their value as indicators of medical care and distort the process in undesirable ways."

I submit that devising better measures will not change the situation.

Dr. Cassel et al would disagree with my view and she closes her commentary with  the usual boiler plate words about "stakeholders"  and better quality down the road. "All stakeholder groups are now invested in getting more  performance out of measurements ,which should ultimately drive the care improvements that patients need and deserve."

 The economist,Arnold Kling, give his take on performance measures or P4P  here.

I have commented on this general subject before and here  the issue of a conflict between P4P and traditional medical ethics is talked about.

The folks at the National Quality Forum can no more negate Goodhart's law than they can make it now longer the case that people respond to incentives.The stakeholders of which Cassel speaks , of course, included the NQF itself as it is in the business of writing quality standards .

Wednesday, June 17, 2015

There are some amazing octogenarians out there

Some  know-it-all-officious-busybodies   medical progressive elite presume to know when various medical procedures should be limited on the basis of age. Some even presume to know how long someone will live as in recommendations regarding limiting of medical procedures for those deemed to have less than ten years life expectancy or using 75 as a cut off date for certain type of screening tests.My pathology professor in medical school was fond of saying when you tell someone how long he has to live they may piss on your grave.Spock's "live long and prosper" butts up against Dr.Zeke's proposed forgoing of preventive measures for those 75 and older, well at least for him, or so he claims now.

Two recent journal articles shed some physiological light on  some  folks in their 80s,folks about whom some of the progressive elite would desire to limit medical care.

Trine Karlsen et al described a remarkable 80 year old Norwegian.The authors believe that the subject of their study may have a world record for maximal oxygen uptake (VO2max). for his age,50 ml/kilo/min.Accordingly to the authors this value is compatible of a normal, active, non endurance trained 35 year old Norwegian man.(How to be 80 year old and have a V02max of a 35 year old, Case Reports in Medicine, Vol 2015, article id 909561). The "how " seems to be to have great genes and to be very physically active.

 To put V02 max  in some perspective; It is a measure of the highest rate at which oxygen can be utilized by the body during intense exercise.It is a function of how much blood the heart can deliver to the muscle ( cardiac output) and how  much oxygen the muscles can take up measured by the a-v oxygen difference.

It is generally believed to peak somewhere between age 25 and 35 and decreases afterwards. Various estimates of the rate of decline have been made. A stylized version is that the decrement is of the order of 5-10 % per decade until about age 70 and then V02 max declines more rapidly.For those who continue to do endurance exercise training the decrease is in the 5% per decade range.Some data indicate that endurance athletes' VO2 max actually decreases more per decade in absolute terms ( ml/minute/kilogram) but since they begin the decline with a higher absolute value their percentage decline is about half of that of the non trained healthy person. In that regard as in most things there are some conflicting data and considerable individual variation. Karlsen's subject has his 02 max measured at age45 so that the calculated decrease in his 02 max  from age 45 to age 80 was a remarkable 2.3 ml/min/kilo per decade while previous reports suggested the average decrease is 5.4 ml/min/kilo per decade. At age 25 he was measured at 75 ml,min/kilo.

World class endurance athletes typically have values in the 70s and 80's. The value of 90 is often quoted as the highest record, this in a 24 year old cross country skier while other publications quote the recording of 95 . The value of 17.5 ml/kilo/min ( 5 mets)  has has been labelled the aerobic frailty level, the value below which a person is by one  imprecise definition, frail, and would find the activities of every day life consuming such a high percentage of their O2 max that fatigue would greatly limit function.A value of 7 ml oxygen /kilo is said to be the lowest level compatible with life.Endurance exercise training programs typically increase 02 max by 10-15% ( with the occasional outlier of more than 30%) but those folks in the 70 plus range can thank their parents ( at least one of them) for their exercise capacity.The sled dogs who race have 02 max values in the range of 240!

Scott Trappe and co authors in an earlier article in the Journal of Applied Physiology ( see here) published detailed physiological data including results of muscle biopsies and muscle enzyme studies on 15 active healthy octogenarians (one actually was 91).Nine were long time endurance athletes and 6 were age matched healthy untrained men without serious medical conditions and who were fit enough to do the exercise testing. Not only had the athletic group been competitive cross country skiers in their youth, they had continued with vigorous programs and all had trained  on average 8 hours a week for the last fifty years. ( Fifty years is not a typo).The endurance athletes had 02 max values between 34 and 42 while the healthy non endurance folks had on average a 21.

And then there is Ed Whitlock.See here for details of his setting the marathon time record for a 82 year old human . He finished at 3:41:58 which is nine minutes 49 second per mile.Whitlock is also noted for being the only man to run a sub three hour marathon at age 70 or older.Estimating his V02 max using table 2.3 from Tim Noakes's Lore of Running ( which is derived from data of Davies and Thompson) gives a value of about 48 ml/kilo/min, which is close to Karlsen's subject's measured value..

addendum: 8/28/2015
Ed Whitlock is not the only 80something who ran a sub four hour marathon. Ed Benham ran a 3:48 marathon at age 82 and Harold Wilson did 3:58 in Boston at age 80. In the half marathon category Anne Garrett ran 2:13 at age 80 .