Category: Surgery

Nancy now has a cardiovertor defibrillator monitoring her heart functions and ready to intervene should said heart develop electro-mechanical problems.  The worst of these, sudden cardiac arrest, can lead to death in minutes.<Insert big sigh of relief here.>

Nancy and I have been playing puppy-tag for the past week – meaning when Nancy would show up at the whelping box I could leave and then I would return and she could leave.  Six of the puppies would likely survive an extended period without intervention but the seventh, a small male, is not bulky enough to keep from getting shoved aside by the others.

One plan was for us to use the pick-up with the canopy and cart mother and pups along to Yakima in separate housing, then there, I could put them together for a bit, then isolate them again, and so on.  The truck is designed for heavy loads and trailer pulling and is a rough rider.  This, I thought, would shake all of the animals, and us, unnecessarily.  Also, when contemplating this maneuver I did not know what the weather would be like.  If “hot and sunny” the back of the pick-up could be like and oven.  So, while doable, this appeared to be a humungous hassle and prone to problems.

Instead of attempting the shake-&-bake approach Nancy enlisted the driving prowess of a friend, R, and I stayed home.  Nancy left home about 7 A.M.  R lives (almost) on the path Nancy would take so the extra time needed was very small.  Nancy got checked in starting at about 8:30, saw a short video on what to expect, got prepped, and began the procedure shortly after 11.  They finished in about an hour and called me shortly after Noon.

Nancy was with a nurse in a room near where the procedure was done and lunch had been ordered.  Sometime in the afternoon she would go to a room to spend the night.  Not knowing any more, that is all I can write.

I (John), being raised in Pennsylvania, took a college class about the geography and history of my home State.  One region we learned of was “The Land of Milk and Honey,” also known as the Wyoming Valley in the northeastern part.  Honey implies bees and bees need blossoms, and blossoms need, what else, Sweet Clover.  [The Wyoming Valley played an important role in the Revolutionary War, including an early battle and later providing food for soldiers.]

Down through the years from the time of settlement sweet clover has been used as a cover crop (for green manure) and as a hay crop in northern U.S. and Canada.  A problem can develop because a component of sweet clover is coumarin.  It has a sweet scent, readily recognized as the scent of newly-mown hay. Some say it smells like vanilla.  In its succulent stems Sweet Clover hay can harbor fungi, some of which can transform the coumarin into an anticoagulant called dicoumarol.

Anticoagulants can be useful or deadly.  Sweet clover was widely used as hay in the early part of the 1900s when a series of wet summers, and lush clover, led to an epidemic of “bleeding disease” in cattle.  One such place this occurred was in Deer Park, Wisconsin in the northwest part of that state.   In 1933 a farmer from Deer Park showed up at the School of Agriculture and walked into a professor’s laboratory with a milk can full of blood which would not coagulate. In his truck, he had also brought a dead heifer and some spoiled clover hay. He wanted to know what had killed his cow.  When the researchers succeeded in isolating the anticoagulant the Wisconsin Alumni Research Foundation (known as WARF) became involved in seeing that the University benefited from the commercial application of the compound.  For a name they concocted Warfarin from WARF + (coum)arin. A major early use was for rodent killer. The compound Warfarin Sodium is marketed by the global biopharmaceutical company Bristol-Myers Squibb as Coumadin®.

Coumadin® (Warfarin Sodium) is used to help prevent and treat blood clots in the legs, lungs, and those clots associated with heart-valve replacement or an irregular, rapid heartbeat called atrial fibrillation.  Despite its effectiveness, treatment with Warfarin has several shortcomings. Many commonly used medications interact with Warfarin, as do some foods, and its activity has to be monitored by frequent blood testing for the international normalized ratio (INR) to ensure an adequate yet safe dose is taken.  The test is used to determine the clotting tendency of blood.

After trial-and-error adjustments over the last couple of months Nancy’s INR has just recently settled into the desired range.  Thus, it seems the appropriate dosage for her has been determined given her current diet, exercise, and whatever else is involved.

So yesterday she stopped taking it.

We are in the approach period for the implantation of a cardioconverter-defibrillator.  The clotting ability of her blood has to happen faster for the procedure to be safe, that is, excessive bleeding is to be discouraged.

We expect the implantation to be on Tuesday, June 1, mid-morning.  One night in the hospital is scheduled and she should be back home by late afternoon on Wednesday.

We’ll celebrate with a warm toasty muffin spread with Sweet Clover honey.

It is said, by whom I have no idea, that life happens while you are making plans.  The truth is, and you can quote me on this, one has to do both.  So we went to Yakima to have a session with an assistant to the implantation doctor.

The session was designed for us to review the reasons for having and ICD implanted and to have the nature of the procedure explained to us.  As I have been searching the internet for information and showing it to Nancy, and summarizing some for this to report here, we were able to ask questions and understand the answers.  There are small pamphlets available at the Heart Center about various heart issues but we find them short of information.  From the internet we can get detailed drawings, photos, animations, and video.  Only about 18 months ago did we get a high speed connection to the Web and we could not have learned what we have without it.

So, back to life and plans.  Life first.  Nancy has developed a sore throat and head cold but these seem unrelated to anything other than being out-and-about. She continues to function doing the things she has, such as music and physical therapy and an increasing number of domestic chores.  This approaching week has been scheduled with master thesis defenses for students that Nancy has had in classes.  Now retired but as an Emeritus Professor she can (and wants to) participate in these activities.  Guess who looks on this situation disapprovingly?  The up-side is that she may throw off the sore throat and cold before she goes to the hospital.

We have managed to squeeze this potential life saving procedure into the very busy schedule on June 1^st — twelve days from today.  With that date set we can back off from that 5 days and cease taking Coumadin® so that Nancy won’t bleed overly-much when the implant is done.  The dropping level of anti-coagulation will be of concern but can’t be avoided.

There is a nice vein below one’s collarbone within which leads can be threaded into the right atrium.  From there the lead will pass through the tricuspid valve into the right ventricle.  Near the bottom of that chamber where the wall-muscle is close to the left-ventricle, the plastic-coated metal lead will be stuck into the muscle (the myocardium).  This will be near pathways (bundle branches) for the movement of electrical signals along and through the ventricular walls.

The device can monitor the heart rhythm and sense and record any problems with the coordinated contractions and relaxations.  As necessary it can slow the beating if it is too fast (called tachycardia, TAK-ih-KAR-de-ah), speed it up if it is too slow (called bradycardia (bray-de-KAR-de-ah), and convert a fibrillating (quivering) pattern into a regular one.  This last situation – especially ventricular fibrillation, can stop the forward motion of blood through the body and lead to sudden death.  See the following for more info:

http://www.nhlbi.nih.gov/health/dci/Diseases/scda/scda_whatis.html

The implanted device is a sophisticated tiny computer with storage and the information it monitors is available for review.  A companion unit can be placed on a bed-side table and then at night the information about your heart will be moved to the bedside, then to a distant computer, analyzed, and searched for anything that suggests a problem.  If anything is found then you and your doctor can be alerted and in you go for a LOF.  Well not exactly but that is what the dealer said when I called about the car – Her exact statement was “So we need to schedule a LOF.”  I had to ask. It’s a lub-oil-filter procedure.  What the tune-up for an ICD is called, I have no idea.

Next entry is “planned” for Sunday morning.  Enjoy your weekend.  Enjoy life!

On Tuesday (May 18^th) Nancy is scheduled to have an examination meeting with an assistant of the doctor who will soon outfit her with an implantable cardioverter defibrillator (ICD).  There are many pages on the web that can be found using this 3-word phrase.  However, the basic concept is that of using something to provide an electric impulse to convert an abnormal heartbeat into a normal heartbeat.  Just a few years ago there was interest in (chemical) medications to accomplish cardioversion (the conversion of one cardiac rhythm to another) but rapid development of implantable devices (following the introduction of the simple pacemaker) has driven the modern usage to be synonymous with defibrillator.  We’ll get to that in a bit.

A Canadian named John Hopps was trained as an electrical engineer (EE) and conducted research on treating hypothermia (cold core body temperature). While experimenting with radio frequency heating to restore body temperature, Hopps made an unexpected discovery: if a heart stopped beating, it could be started again by using an electric impulse.  By 1950 he had developed a rather large device that could be used (externally) as a pacemaker.  Shortly after that another EE named Wilson Greatbatch had his own eureka moment that inspired his invention of the implantable cardiac pacemaker, and following that he developed the corrosion-free lithium battery to power it.  Wilson Greatbatch is thus considered the inventor of the pacemaker.

The 60 years following these early inventions has seen rapid progress in understanding the electrical nature of the heart, electrical-electronics concepts, and miniaturization capabilities.

The heart is a 4-chambered muscle with blood from the body seeping into one chamber from which it is then forced out when the muscle contracts in response to a body-generated electrical pulse – the beginning of the heartbeat.  That impulse is developed and sent out from the sinoatrial node, often called the SA node. This is located on the inside surface of the upper-right part of the heart in the Right Atrium – the chamber into which oxygen-depleted blood from the body seeps.  When this chamber contracts blood is sent to the chamber below it – the right ventricle – by way of the tricuspid valve.  The blood in the right ventricle will go to the lungs for a fresh supply of oxygen.

Re-oxygenated in the lungs the flow from there is collected in the left atrium, also an upper chamber.  That blood will next pass into the lower chamber on the left – the left ventricle – which is the largest chamber of the heart and its contraction forces blood out into the body.  The more the wall muscle is stretched, the more forceful the contraction and the better the body’s cells receive oxygenated blood.  The mitral valve opens to allow the flow from the left atrium into the left ventricle.  It closes for the contraction so that the blood goes out into the body and not back up into the left atrium.

There is a lot to go wrong as the heart beats, pressures rise and fall, valves open and close, and blood flows.  The electrical impulse that starts in the SA node in the upper right has to move in perfect rhythm to the different parts such that each job is done in collaboration with the others.  One of Nancy’s major problems – now fixed – was the poorly performing mitral valve.  Because some of the blood was forced back into the chamber above it, the blood from the lungs seeping into the left atrium was encountering pressure that should not be there.  That blood should have been going through the aortic valve, into the aorta – the major artery supplying fresh blood to the entire body. The imbalances of pressures and the leakage caused the heart to enlarge.

Also, the left atrium contraction fills the arteries that supply the heart muscle with oxygen.  The two main arteries (lying on the outside surface) of Nancy’s heart were narrowed and this was the site of the clot that sent her to the ER on Friday following Thanksgiving.  The lack of oxygen-rich blood to this part of the muscle caused damage/death to some of the cells of the heart wall.  Thus, it doesn’t stretch and contract as it should.  Furthermore, (the following seems reasonable to me but I can’t find a web article to confirm it) the stretching and dying of the heart wall should alter the paths and timing of the electrical signals flowing down through the heart.  It seems to me that the heart is working around this damage but is more likely to loose its natural rhythm (experience arrhythmia).  When the left ventricle is experience this loss of natural rhythm it is called ventricular fibrillation (v-fib) and instead of stretching and contracting normally the muscle quivers rapidly and irregularly.

When this happens, the heart pumps little or no blood to the body. V-fib is fatal if not treated within a few minutes.  Most cases of sudden cardiac arrest (SCA) are caused by ventricular fibrillation.  What actually sets the heart into v-fib is another matter but studies show that it is more likely to happen when the efficiency of the heart as measured by the ejection fraction is below 35%.  Scroll back to the page for SUNDAY – April 25^th where, in the bottom part, this is explained further.

If any part of the heart is experiencing fibrillation (and it is serious) than the solution is to convert it into a normal rhythm, and thus is born the term defibrillation.  The thing that does this is a defibrillator based on the idea of the conversion of a bad rhythm into a good rhythm.  Modern science and medical technique now can miniaturize the necessary components, doctors can implant the unit under a person’s skin with leads to the heart and should the fibrillation occur the patient is saved by the implanted cardioverter defibrillator (ICD).

Simple really.  We are off to the heart clinic on Tuesday to set the plan in motion.

We went to sleep last night expecting a freezing temperature at daybreak this morning.  We are finishing breakfast while watching deer amble around the back fence just 30 feet away and the thermometer reads 40 degrees Fahrenheit (~5C).  The sky was clear last evening and (apparently) expected to stay that way so we would have experienced rapid radiative cooling.  Instead, the flow of the jet stream shifted unexpectedly our way from over the Pacific Ocean just off Washington State’s NW corner.  That shift brought enough moisture into our atmosphere to prevent the cooling we were told to expect.  Either that or there is one huge forest fire sending a pall of smoke and warmth our way and covering the sky.  Without further investigation it is hard to tell.

Nancy’s recovery is continuing but there too is an unexpected turn.  I suppose it is unexpected for us but not for the cardiologists involved in her case.  (Metaphor alert!)  They, having been years at this, are not surprised by much and have gone down all the various paths, even those less traveled.  At our recent appointment, the receiving (or check-in) nurse was a heart patient and the doctor too.  His pulmonary valve had been replaced by the same surgeon that replaced Nancy’s mitral valve.  About 8 years after the replacement that tissue valve began to fail and he then had an artificial valve implanted.  The parts in our truck don’t last that long but, still, when you fix something you like to think it will stay fixed.

With hearts there are many things to measure besides beats per minute and the one at the top of the list today is called the ejection fraction.

Below is a link that gives a clear explanation:

http://www.medhelp.org/posts/Heart-Disease/EJECTION-FRACTION-/show/869616

“Ejection fraction (EF) is a measurement of how well the heart is pumping.  It represents a percentage of the total blood volume in the left ventricle that is pumped (ejected) with each beat of the heart.  As with any pump not all of the liquid is pumped out with each cycle.  Normal EF is in the 50-60% range.  Values higher than this are termed “hyperdynamic”, meaning that the heart is forcefully contracting.  The lower the EF the worse the heart function.  A general breakdown of values is as follows: 40-50 % mild dysfunction; 25 – 39% moderate dysfunction; < 25% severe dysfunction.”

The most recent test of Nancy’s heart (done when she went to the ER a few weeks ago – and under the stress of excess fluid) showed and ejection fraction of about 25% — note this is about half the normal as defined by the above statement.

Nancy’s heart also exhibits atrial fibrillation. The Mayo Clinic staff have a description of “a-fib” on the web:

http://www.mayoclinic.com/health/atrial-fibrillation/ds00291

As I read that I think of the most recent truck repair – replacing all the wiring components that keep the spark plugs firing well and in proper sequence.  I knew this work need doing and so, just before we went to pick up the new horses, into the mechanic we went.  I hate breakdowns at any time, but with 3 horses that are new to us and on an interstate highway such an episode is to be avoided.

Well, the human body functions with electrical impulses also and those that are directing Nancy’s heart are a little bit in need of help.  The help comes in the form of a modern “pace maker” and is called an implantable cardiovertor defibrillator or ICD.  The link here is helpful:

http://www.nhlbi.nih.gov/health/dci/Diseases/icd/icd_whatis.html

The very last paragraph of the above page mentions a special procedure called cardiac resynchronization therapy (CRT) involving a device able to pace both ventricles at the same time.  Nancy’s primary cardiologist suggested we discuss this route with the implanting specialist.  His opinion, at the moment, is that this is a less traveled road and one she need not take.

This will be a short description of Nancy’s open heart surgery.  I’ve used notes from the surgeon and information taken from the internet.  I’ve changed most of the medical terms to simple English and in the process reduced the accuracy.  I’ve added links where I’ve found helpful drawings and information.

When the operation was completed Nancy had a new valve and two replaced sections of artery leading to parts of her heart.

This link shows the location of the parts of the heart.  Note the location of the ‘left atrium’ because that is how one approaches the mitral valve.

http://en.wikipedia.org/wiki/Mitral_valve

The heart needs oxygen rich blood that is provided by arteries and when these become narrowed by disease the muscle of the heart suffers or dies.  Two arteries needed to be replaced.  One of the larger heart arteries is called the “left anterior descending” (LAD) coronary artery.  Its location is shown on this page:

http://www.texheartsurgeons.com/cad.htm

From the main arteries are branches or “diagonals” and one of these also had reduced blood flow from clogging.

To get to these arteries and the mitral valve Nancy’s chest had to be opened.  This is done with a reciprocating saw with the same basic design of a wood worker’s tool you buy at the hardware store.  The design is more refined and the blade is short – it only has to be slightly longer than the breast bone (sternum) is thick.  The location of the sternum is shown here:

http://en.wikipedia.org/wiki/Sternum

A photograph of one brand of sternum saw is shown here:

http://www.terumo-cvs.com/products/ProductDetail.aspx?groupId=6&familyID=114&country=1

You will sometimes hear of “breaking” the chest bone but the instrument of choice is a saw and not a hammer.  Here is a link to a video that shows the chest being opened.  There is some blood, but not a lot, and you get a look at a beating heart.  If you feint at the sight of blood skip this or sit down in a comfy chair.

http://www.youtube.com/watch?v=r7RsB0BA4EI

Once the surgical team gets the chest open the blood flow to the body is maintained by bypassing the heart with a “heart lung machine.”   The concept is shown here:

http://biomed.brown.edu/Courses/BI108/BI108_2004_Groups/Group03/HeartLungMachine.jpg

And here is a picture of the real thing.

http://heatherwritesablog.files.wordpress.com/2009/06/heart-and-lung-machine.jpg

Much more complex.  The issue is to take the heart “off line” and repair it while maintaining blood flow to the rest of the body.  You can read about it here:

http://en.wikipedia.org/wiki/Cardiopulmonary_bypass

An issue in all of this is that you do not want the patient to get blood clots while doing the surgery so an anticoagulation chemical is necessary but you then need to put the parts back together with sufficient clotting ability in the blood so that they don’t leak around every suture.

Nancy managed to complicate this already complex issue because of her serious allergic reaction to heparin, the anticoagulant of choice.  For her they used a chemical called Angiomax.

The next issue is that the heart will be stopped and disconnected from the blood supply and both the patient and her heart will fare better if all this is done at a lower temperature.  So she was cooled from a normal 98.6^o F. to 86^o F. (37^o C. to 30^o C.).

Her heart was stopped by using cold blood (with added potassium) put into it by way of both the main artery and vein and kept cold by repeating this every 10 minutes.  This is called “cold potassium blood cardioplegia” with the last word meaning “paralysis of the heart.”

A vein from near the surface on the  inside of her left leg, above the ankle, was “harvested” and used to replace the “diagonal” artery.  The vein used is called the “saphenous” vein (clearly seen) as it is close to the surface of the body and can be seen under the skin.  When the body is too hot the body shunts blood from the deep veins to the superficial veins, to facilitate heat transfer to the surroundings.  Normally this vein doesn’t get a lot of blood volume and so can be removed without harm.

Next the “left anterior descending” or LAD  was bypassed.  For this they used an artery found within the chest cavity called “left internal mammary artery” or LIMA.  There is also one on the right side.  These unique blood vessels run along the inside edges of the sternum, sending off small branches to the bones, cartilage, and soft tissues of the chest wall. For unclear reasons, the IMAs are remarkably resistant to cholesterol buildup and thus a good choice for replacing an important heart artery.  Read more about the IMAs here:

http://www.hsforum.com/stories/storyReader$1491

To replace the mitral valve the left side of the heart has to be opened.  This is called “left atriotomy” —  meaning cutting open the upper chamber on the left side of the heart (the atrium).  Nancy’s mitral valve was in need of replacement and (apparently) dead bacterial ‘vegetation’ from last summer’s endocarditis was also found there. The attachments that make the valve work were shaved some to make them work better.  The old valve was cut out and a replacement from a pig (a 33 mm Hancock II porcine prosthesis) was set in and sutured into place.

With the new valve in place the surgeon than had to close the opening in the heart.  As they worked their way back out of the chest cavity they re-warmed Nancy’s entire body and sent warm blood back into the heart.  Her heart came back to life with a single electrical shock.  It started with a normal rhythm, which in medical terms is called “sinus rhythm” but the use of the term ‘sinus’ likely derives from a mistaken idea and so has only historical context for its continued usage.  She was on the heart-lung machine for 100 minutes.

On a normal patient the surgery would be about over at this point.  But for Nancy there was a long wait ahead.  The blood thinning issue meant she would stay in danger of excessive bleeding for some time.  With all the major and minor cuts and sutures in her chest cavity there were lots of places for something to leak.  So they waited.  First they waited for 3 hours with an open chest, watching and monitoring the instrumentation, and testing the clotting time (ACT = activated clotting time). Then they closed the chest and stayed with her in the operating room for another hour.  She spent from 9 in the morning until about 4 in the afternoon with the operating team.  Then she was returned to the ICU, a room full of instruments, and watchful nurses.

The operation was on a Tuesday.  Watchful waiting lasted into Thursday.

Then the ventilator was taken away and slowly other sensors and monitors were removed.  About Friday Noon the ever-vigilant nurses started to relax.

Nurses from earlier days, doctors, and many others started coming by, standing at the foot of her bed, smiling, and giving her 2-thumbs up.