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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 ...

Thursday, January 21, 2021

Battery problems with Medtronic Pacemakers, actual battery drainage and battery life estimation error

 The leads in a pacemaker (PM) is said to be the Achilles heel of those systems.A close runner up in the Achilles heel competition is the PM battery.

In 2019 Medtronic reported problems involving batteries.

In one case the problem did not  pose an imminent threat to patients as the issue was that some of their units (manufactured between October 2018 and January 2019 ) were displaying erroneous estimates  of battery life. The problem was said to be in the "programmers" and not in the units themselves and battery life was not altered. The term programmer here refers to the computers that are used to communicate with the PM in the doctor's office and to make programming changes and to make updates to firmware.

A much more serious battery issue also was reported in 2019.There were three reports of pacemaker batteries being completely drained resulting  in one death.The devices involved with this problem were the following models: Astra,Azure,Percepta,Serena,and Solara.Damage to a capacitor in the units was said to be the cause of the battery drainage. Unfortunately there was no way to determined if a given Pacemaker was likely to have a battery failure. The FDA was not recommending  replacing all of the units.Some 131,000 units were potentially affected.

PMs can be "interrogated" by bedside monitors providing various parameters of PM function including a value for battery life estimation.

In theory battery life determination seems  simple.It is the battery drain rate divided into the battery capacity which is measured in ampere hours. The devil is in the denominator of the equation. How accurate are these estimations.

My own PM was  implanted in October 2015.I am writing this in January 2021 .

An interrogation done on October 2016 gave an estimate of 2-2.5 years which corresponds to October 2018 to June 2019. An interrogation done October 2017 gave a estimation of 1.5 to 2.5 years which corresponds to June 2018 to June 2019.IN January 2021 the estimate was 4 to 10 months. By May the estimate was still 4 to 10 months.

So at least as regards my PM the estimations of battery life do not instill confidence. 

Addendum 5/17/2021 undated battery estimates were added to the next to last paragraph. 


Longevity in athletes -good genes,exercise levels or both

 There are several reports suggesting that endurance athletes enjoy good longevity .These studies have involved professional cyclsits,Ski racers,French oarsmen and Harvard rowers. 

Do the  genetic endowments that world class endurance athletes possess that facilitate their athletic ability also either alone or with other genetic contributions enable to live longer? Alternatively is it the long hours and perhaps years of exercise that lead to a long life? Maybe both.

A key, perhaps the key,to be a world class endurance athlete is a high maximum oxygen uptake (02Max).Although intense aerobic training can increase one's 02 max a moderate amount  (maybe 10-15%),world class endurance athletes inherit high 02 max values. A typical 25 year old man may have a value of 40-45 ml/kilo/minute while a budding world class marathon runner typically has a value of 80 or higher with few exceptions.Values as high as 90 have been recorded in some world champion cross country skiers. 

The prodigious exercise capacity of elite endurance athletes is characterized by a slightly larger than normal ventricular size with great capacity to fill quickly.

The maximal oxygen capacity of humans inexorably decreases over time.Whether continuing moderate or even high levels of aerobic exercise will mitigate that rate of loss is the topic of an ongoing debate.

 What is clear,however, is that if you have for example a 02Max of 60 or 70 when you are thirty years old you are more likely to have a 02 max in the high 20s or low 30's when you are 75 or eighty.

A  80 year old with a 02 max of 28 is more likely to come out the other side of a serious illness or accident than an 80 years with an 02 max of 18 or 20. 

 Practice,practice practice arguably may get you to Carnegie Hall but someone with a 02 max of 45 will not win the Olympic marathon regardless of how much training he endures and you will not have a 02 max of 50 when you are 80 years ( Ed Whitlock had an 02 Max of 52 at age 82))  unless you  had a very high  02 max in your youth.

For more on Ed Whitlock and how he slowed down marathon time wise during his 70's while his O2 Max seemingly was unchanged, see here.

Tuesday, January 19, 2021

Late gadolinium enhancement at Right Ventricular insertion points in highly trained endurance athletes

 A study from Spain (1)demonstrated late gadolinium enhancement in 37 % of highly trained young endurance athletes, all of which occurred at the insertion points of the right ventricle into the inter ventricular septum.See here for full text of article.

All of the athletes trained at least 7 hours per week for the previous five years.Compared to controls the study group had a 10 fold increase in late gadolinium enhancement (LGE) .

LGE is seen in patients with coronary artery disease with  a post myocardial infarction scar and in cardiomyopathy patients in whom the LGE may be considered a negative prognostic sign.

Early reports of LGE in older , long time endurance athletes were confusing and in one study confounded by a significant number of cigarettes smokers. Some of the cases demonstrated a coronary artery pattern ( i.e. LGE along the distribution pattern of the coronary arteries ) and some did not and some were noted in the insertion point of the right ventricle.

The authors described the LGE as a possible "matrix remodeling" and along with bi-atrial and bi-ventricular chamber size increase and superior diastolic function characterizes  the pattern of  the so-called athlete's heart.

1)Domenech-Ximenos,  Prevalence and pattern of cardiac magnetic resonance in highly trained endurance athletes Journal of cardiovascular Magnetic Resonance 2020 Sept 3, 22,(1) 62