GENERAL ARTICLES

HEARTS are PUMPS

Your heart is a marvellous machine. But it can set out of order ... A doctor discusses heart disease and what can be done for it

Albert Hemming, M.D. October 15 1944
GENERAL ARTICLES

HEARTS are PUMPS

Your heart is a marvellous machine. But it can set out of order ... A doctor discusses heart disease and what can be done for it

Albert Hemming, M.D. October 15 1944

HEARTS are PUMPS

Your heart is a marvellous machine. But it can set out of order ... A doctor discusses heart disease and what can be done for it

Albert Hemming, M.D.

HEART Disease! Probably no other verdict in medicine carries with it, in the ears of the layman, the ring of the death knell more than this dread phrase. Instinctively it evokes a vision of life haunted by the possibility of sudden and unheralded death—a future of grim waiting for the lightning which, sooner or later, must strike at the slender thread which attaches the sufferer to life. This is a forbidding picture, its outline of truth obscured by the gaudy coloring of misconception and ignorance. The fact is that the heart is a faithful and steadfast friend to its owner, not given to sudden treachery. It sweats out his fevers with him and palpitates with his emotions, and when stricken with disease it fights for its life and the life of its owner with a dogged perseverance that is matched by no other organ in the body.

Anyone who doubts the fidelity of the heart should consider for a moment the debt of gratitude which he owes to this 10-ounce flesh and blood dynamo. Given the power of speech, any one of the 25 billion blood corpuscles it pushes around the body with clocklike regularity could tell him. Seventy times a minute they receive a vigorous push to keep them moving, a push which is initiated by a beat of the heart. In 24 hours the heart squeezes out its content of blood just about 100,000 times. To sustain an individual through an average lifetime, it must beat between two and three billion times. Perhaps, compared with a modern airplane engine, its power-weight ratio might not make an impressive showing, since it would take well over 200 human hearts working together to develop one horsepower. But the aircraft engine is serviced after every flight, whereas the heart may beat for as much as a century without benefit of ground crew or refitting.

To say that the heart is a pump is a commonplace, hut the exact how and why of its workings are a little more complex than might be gathered from this bare and uninspiring statement. The adult human body contains about two and a half gallons of blood, just about 10 times as much as a blood donor gives at a single sitting. In this amount of blood there are approximately 25 billion red corpuscles, those little rounded globules which carry the oxygen from the lungs to the other tissues of the body. The sole purpose of the heart is to keep an endless column of blood on the move so that the life-giving oxygen contained in the corpuscles and the nutrients contained

in the fluid part of the blood are maintained in a constant flow to the tissues. The piping system through which this constant traffic flows is made up of arteries and veins, the arteries being the thick-walled blood vessels which carry the freshly oxygenated blood from the heart to the tissues; and the veins being the more delicate tubes which conduct the “stale” blood back to the heart once more.

Essentially, the heart itself is nothing more than a hollow muscular bag, which by alternately expanding and contracting exerts a pumplike action on the blood which flows through it. In the earthworm the heart is seen in its simplest form. A little careful dissection of this animal reveals that the main artery of the body runs along the back. In the living animal periodic waves of contraction pass along this tube, emptying it of its blood just as a finger and thumb passed along a rubber tube will empty it of its contents. With no other assistance this versatile artery acts as the heart of the earthworm.

In the unborn baby the human heart has its beginnings in an almost identical manner. But a plain bulge on a blood vessel, although it may be good enough as a heart for such a sluggish beast as the earthworm, is nowhere near efficient enough for a warm-blooded animal given to strenuous activity. So, during the course of life within the womb, the heart develops into such a strong, highly specialized organ that it is easy to lose sight of its essentially simple nature.

If you hear a physician speak of the right heart or the left heart, you may he tempted to think that he is referring to the Siamese twins or some similar circus monstrosity. Such is not the case. The human heart is divided lengthwise by a membrane. Both sides of

the heart beat together but the blood on the two sides does not mix. 'The explanation for this arrangement may be seen from a very simple illustration. 'Pake a pencil and draw the figure eight. There is the simplest possible diagram of the human circulation. One loop represents the circulation through the lungs and the other the circulation through the rest of the body.

Every corpuscle in the blood must follow an extremely similar path to that traced by the pencil in drawing this figure. Now', to make it more lifelike, imagine a closed ring of hollow rubber tubing twisted into the form of an eight. Right at the centre is the heart, and at this point the tubing is double, just as the heart is. If the tube were filled with blood every corpuscle that did a complete circuit of the eight would have to pass through this centre point, that is, the heart, twice. Similarly, to do a complete circuit of the human circulation a blood corpuscle has to go through the heart twice, first through the right heart and then through the left.

A corpuscle which had just completed the circuit might describe its experiences thus: “At Zero Hour 1 was catapulted from the right heart into the smaller loop of circulation through the lungs. As I passed through the lungs 1 picked up oxygen from the air which was being breathed and my complexion changed to a bright healthy red. 1 then completed the loop and found myself back in the heart, but this time on the left side, having taken just about six seconds to complete this one loop of the circuit.

“A fraction of a second after returning to the heart, I was hurled again into the circulation, this time into t he larger loop of circulation to all organs of the body.

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Hearts Are Pumps

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By chance I was swept into the arteries leading to the foot. As I passed

through a muscle in the foot, I gave up my oxygen to it and instantly turned a deep asphyxiated purple. Emerging from the muscle I found myself in a vein. Once more I was caught up in the current and in a matter of seconds I was back at my starting point in the right side of the heart.”

Such is the life of a corpuscle. Twenty seconds or so for the round trip, and 3,000 round trips a day. Small wonder that few can stand the pace for more than three weeks of life!

Just one little point that in the excitement of the moment the corpuscle forgot to tell us—that both entrance and exit to the heart are controlled by one-way trap doors, the heart valves. As it entered the heart the entrance valve had closed behind it, thus preventing its being thrown back into the vein from which it had just come. Then, at exactly the same moment as the walls of the heart had begun to close down on it, the exit valve had opened and the corpuscle, with millions of its fellows, had poured out into the arteries.

Important things, these valves! Without them the blood would just bob backward and forward aimlessly like a bubble in an eyedropper. With them the blood is kept flowing constantly in the same direction around that never-ending figure eight.

Why Does It Beat?

Perhaps the most fundamental question to do with the heart is—why does it beat at all? No other muscle in the body contracts and relaxes with this clocklike regularity. Scientists have racked their brains for years over this question and the only answer that they can give is that it beats for just the same reason as grass grows or canaries sing. It is in the nature of the beast. This is shown by the fact that an animal’s heart can be removed from its body and kept beating for hours and days so long as it is provided with a liquid that constantly replenishes its energy.

But in spite of the fact that its beating mechanism is largely automatic, the rate at which the heart beats is ordiarily controlled by a subconscious part of our brain. This control centre is connected to the heart by two sets of nerves, one of which is used for speedup and the other for slowdown signals. The control centre itself, being extremely sensitive to changes in the blood which indicate the need for more oxygen, can thus regulate the pace as the necessities of the moment dictate.

When physicians get into conversation about heart disease they are liable to indulge in such jawbreakers as “aortic atherosclerosis” and “paroxysmal auricular tachycardia.” But do not be discouraged by a few polysyllabic words. The essential features of the commoner forms of heart disease are quite simple to understand. For a farmyard pump to do its job well, there must be a strong right arm at the handle and a watertight valve which holds. For its flesh and blood counterpart, the heart, to do its job efficiently, the heart muscle— which represents the strong right arm - must be capable of a strong pumping action, and the valves must act freely so that there is neither obstruction nor backflow. As long as both valves and muscles are healthy, the heart can stand up to as strenuous a workout as its owner can give it.

In heart disease either the valves or the muscles, or more frequently both,

fall down on their job. What causes the heart valves and muscles to weaken? Any medical textbook can supply a veritable mail-order house | catalogue of diseases which may lead to heart trouble. But in practice the situation is not nearly as complicated. Speaking in the broadest generalities, heart disease, in most instances, begins in youth or childhood or in the later years of life. Although it may first become evident in middle life, it has more often than not had its unnoticed beginnings in school days or youth. In the form of heart disease which commences in the earlier years of life, that vandal of juvenile health, rheumatism, is almost always responsible. In the J elderly, disease of the arteries, with or without high blood pressure, is the i condition which most frequently drags ! heart disease in its wake.

Rheumatism is a double-edged wea¡ pon—it strikes at both the valves and ; the muscles. Sometimes it strikes with I the violence of a cyclone and lays the | patient prostrate with high fever and ; swollen joints. Sometimes it is so ¡ insidious that it amounts to no more than “growing pains.” Often it comes back again and again, this time with fury, that time with a twinge, until the victim finally “outgrows” it.

The damage which it so frequently does to the heart is often not evident at first, sometimes not until the rheumatic pains have become no more than an unpleasant recollection. “Warts,” not on the skin, hut on the heart valves along the edges of the folds which come together when the valve is in action, are usually the first manifestation of rheumatic heart disease. These tiny growths seldom impair the efficiency of the valve in the early stages but as they grow they eat away the edges of the valve folds or cusps, as physicians call them. As months or years go by the cusps become thickened and hard in response to the irritation, and in the final stages they change from delicate pliable membranes, whose trim edges float easily together, to frayed and ragged pieces of parchment.

Anywhere between the heginningand end of this change the eating-away process may stop, leaving the patient with a greater or lesser degree of valve damage. Usually, however, the damage | is progressive, sometimes continuous, j sometimes in intermittent spurts with j long intervals of inactivity between.

Valves May Stick

The net result of the disease process, however, if it goes far enough, is a | valve which neither opens nor closes properly. When the heart contracts it has to do so with such force as to overcome the obstruction provided by a j valve which may not he more than half open. At the conclusion of the beat, j when the heart relaxes, part of the j blood which it has just expelled at such great effort comes gushing hack because the valve cannot contain it. It is all rather like blowing up a football with a pump that has a faulty valve. To get the ball blown up at all you have to j work three times as hard and three ! times as fast as with a pump with a j leakproof valve. That is the only way j of dealing with the problem and it is | the way in which the heart tackles the job.

As a man sits slumped in his armj chair his heart is ticking over at mere j idling speed. If he gets up and goes for ; a brisk walk it steps up its pace to a comfortable “coastalong.” But should he decide to run a mile at top speed every ounce of the heart’s energy is called upon to turn out blood, perhaps three times as fast as when he was comfortably ensconced in his chair.

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In other w ords the healthy heart has an enormous reserve energy which it can call upon in times of stress. This reserve energy is the currency w hich is deposited to the heart’s credit in the Bank of Life. Never, under any circumstances, must this account be overdrawn. But in a heart with a faulty valve half the reserve energy may be used up in compensating for the inefficiency of the valve. Even when its possessor is slumped in an armchair the diseased organ may have as much as it can comfortably do to pour out sufficient blood into the circulation. There is little energy to J spare for walking, and an attempt to I run might bring about fatal collapse.

Stated in cold-blooded terms these facts sound grim, but there is a brighter side to the picture. Occasionally rheumatic damage to the heart valves seems to progress to a fixed point and there ceases. In such a case there is no earthly reason why the patient should not live to a ripe old age, provided he does not overdraw his reserve energy by adopting furniture moving or weight lifting as a hobby. In most instances, however, once a valve is damaged, the damage is slowly progressive. For all that there may be 10, 15, even 20 or more years of useful life before the patient. The whole secret of prolonging life lies in conserving the reserve energy, by cutting out those activities which cost too much of this vital currency.

But before we dig too deeply into the problem of treatment, let us take a look at the other form of heart disease which is so prevalent, the type which occurs in the man w'hose hair is greying at the temples. A little hardening of the arteries happens so frequently in ageing men and women that it may almost be looked upon as part of the process of growing old. As long as it is not severe it does no particular harm and the individual often dies of pneumonia or old age long before his hardening arteries have caught up with him.

Sometimes, however, the process may begin at an earlier age than usual or may progress more rapidly than is customary. When this happens the heart is dealt a double blow. It luis to pump against the obstruction put up by inelastic arteries with a musculature that is weakened by a defective blood supply. The heart muscle, like any other muscle, needs blood for its nourishment. In fact, being the hardest worked muscle in the body it requires it in proportionately greater quantity. To supply this need there are two arteries: the coronary arteries, which double back from the main artery, leaving the blood to dive deep into the heart muscle.

When the other arteries of the body harden, these vital blood vessels share in the process too. These vessels, which above all other should remain elastic and healthy, slowly contract until they become as rigid and narrowbored as pipestems. The result is that to supply all its energy and rebuilding requirements the heart receives only a thin trickle of blood, a mere fraction of the quantity it normally receives. Like a grossly anaemic child, the muscle becomes listless and weak and its efficiency as a pump diminishes.

There Are Warnings

Events from there on may follow one or other of several different paths. If the arteries of the heart become extremely narrowed they become liable to sudden blockage by a clot and death may rapidly—though not necessarily— ensue. Frequently, in such cases, the blood pressure is raised much above its normal level, placing the patient in con-

stant danger of a stroke. If neither of these events occur the heart may slowly give up the unequal struggle, the patient eventually dying of heart failure.

Condensed into a few lines it sounds like a grim and rapid fate, but none ot these deaths comes upon the patient without casting its shadow before it. Though the end may be sudden, the twilight descends slowly over the years. A man’s arteries may begin to harden when he is 40, but that is no certain reason that he will not live to be 70. For 20 years he may suffer no symptoms, and for 10 nothing more fearful than what might be considered as a whispered warning that he is but a j mortal whose span of years is numbered. By almost any yardstick it is a gentle and kindly death.

These two main types of heart disease, incompetence of the valves and weakness of the heart muscle, have been described as two separate diseases occurring at different periods of life. It should not he concluded, though, that the valves and the muscle can lead independent lives as far as disease is concerned. In rheumatism, for instance, although the valve damage is usually more obvious, the canker eats into the | heart muscle too, and in the final I analysis the damage to the muscle is more important than the damage to the valves. Conversely, in the weakened heart of old age the valves often become hardened and frayed, but it is the weakness of the muscle which dominates the picture.

Rheumatism and the degenerative changes that go along with advancing years probably account for 80 to 90% of all heart disease. A small proportion of the remainder is accounted for by ; those victims of nature’s malice who are born with hearts that are imperfectly formed. Syphilis rots the arteries ot some. A few fall prey to that malig, nant and rapidly progressing form ot valve disease which occasionally follows an acute bacterial illness such as pneumonia. Sometimes, too, this type of disease, particularly diphtheria, causes a fatal weakness of the heart muscle. With all these various types of heart disease, the speed with which the disease progresses may depend upon the cause, but aside from that, an incom| petent valve will produce essentially the same results whether it is caused by ¡ syphilis or rheumatism, just as weakness of the heart muscle produces the j same results whether the weakness is ! due to diphtheria or to defective blood i supply.

So much for the mechanics of a weakened heart. What does it all mean translated into terms of little Johnnie up the street who, rumor has it, suffers from a rheumatic heart, or the old lady whose lips are slightly blue and who puffs and blows like a grampus whenever she boards a bus?

We will assume the little boy has had rheumatism in one form or another and as its aftermath he has a heart valve which is just not quite so good as it used to be. If his doctor was very astute he caught the disease right at its very beginnings. He could not cure it, because there are no known means by which to do this, but he did the next best thing. He ensured as easy a time as possible for the heart by keeping Johnnie strictly confined to bed until he felt that the active disease process had abated. So now Johnnie has a heart with a slightly leaky valve, but for the time being, at least, it seems to be ; getting no worse.

Some of the reserve energy of the heart is being used to compensate for the faulty valve but there still seems a fairly ample margin to spare. If the condition stays “put,” the boy may live his normal span of years just as if ¡

his heart were healthy, provided he does not continuously overtax his heart strength by indulginginviolentexercise.

But the physician, being wise, does not rely on any such luck. To make sure that the heart shall last just as long as possible he regulates Johnnie’s life, his eating, sleeping, and exercise habits, in such a way as to keep the strain on his circulation comfortably within the limits of its capacity. From time to time he examines him and if there is any sign of a “flareup” he curtails his activities sharply.

In this way he hopes to baby him along into adult life, when the likelihood of recurrence of the active disease becomes less. What measure of success he will meet is difficult to foretell. If the gods smile the boy may live to be 90 and die of old age. If the fates are malignant his life may be snatched by acute rheumatic fever within the next six months, despite all the physician can do. But outside these possibilities it is safe to predict that he has an excellent chance of becoming a useful middle-aged citizen, even though perhaps he will never make “old bones.”

Early Care Needed

But supposing his parents had not been attentive enough to secure him proper medical attention, Johnnie would have continued his swimming and his basketball just as before. Although his heart valves would be rotting there would perhaps be no symptoms beyond a little listlessness and a slight pallor about his face, until irreparable damage had been done. Then he would begin to get more than usually breathless when he ran. As time went on he would have to give up running altogether, because he would collapse completely when he tried.

He might suffer periodic attacks of “grippe,” which would in reality be rheumatic fever.

On the other hand the disease might run its course, as insidiously as it started, until a bluish tinge replaced the pallow in his cheeks and eventually led his parents to take him to the doctor. What the physician would see then is an all too familiar sight to the eyes of the medical profession. The heart, by a combination of stretching and growing, would probably have enlarged to somewhere near twice its normal size to cope with its unfair burden. Its heaving pulsations would probably be visible from the other side of the room. A hand laid flat on the chest would feel the heart vibrating at each labored contraction.

Obviously the margin of reserve energy, the deposit in the Bank of Life, is almost exhausted. Even with the best of care such a failing heart can be kept alive only for another year or two. From start to finish the process may have taken only months or it may have taken years. No physician can foretell its speed—only the final outcome is certain.

The problem of the old lady whose breath is short and whose lips are blue may at first glance appear fundamentally different. Of course she could be in the last stages of rheumatic heart disease but in view of her age the probability is that she has a heart muscle weakened through senility and poor blood supply. Because of her age, too, her arteries are probably thickened and hard and her blood pressure raised, and maybe her heart valves just a little ragged and worn. The very fact that her lips are blue shows that her blood is not being oxygenated properly—in other words that her heart is already failing to keep the circulation up to par.

In the little boy’s case the heart muscle had to fight to overcome the loss of efficiency caused by a faulty valve.

The old lady’s heart has to fight against the resistance put up by hardening arteries. The cases are similar except for one crucial difference. The boy’s heart muscle, at least befôre the onset of the disease, was lean and strong. The ; tissuas of the old lady are naturally senile and weakened. No matter what treatment she receives her condition will surely be progressive, maybe slowly, but inevitably. But there is no inherent tragedy in this situation. She has lived her life and is now nearing the end of her natural span. If the physician can extend her remaining years by a few weeks or months, the while keeping them comfortable, she has cause for gratitude.

It is only natural to ask what the physician can do in the face of heart disease, beyond regulating the patient’s life. Is he restricted to standing by, a mere interested onlooker? The answer is both “Yes” and “No.”

It must be admitted that in this situation he is no master technician with a bagful of miracle drugs.

Paradoxically enough the one drug he holds which makes any pretence at miracles, digitalis, is chiefly of value in pulling his patients from the brink of the grave and is relatively useless in the early stages of the disease. To add insult to injury, even that he acquired from an ignorant old lady, who brewed it from foxgloves. But that is only the belittling side of the story. Far as he has yet to go the physician’s skill saves thousands of lives annually which would otherwise be lost from heart disease. His chief weapon is not a miracle drug but early recognition, diagnosis before the disease has passed beyond its incipient stage.

With heart disease, to know the danger is sometimes to avert it and almost always to postpone it. In its early stages it can be tricky and difficult to detect. Time was when it was scarcely ever diagnosed until the patient’s complexion was a deep heliotrope and his heart pulsations vibrated him from stem to stern. Now by the aid of X-ray, of electrical tracings of the heartbeat, and a dozen other diagnostic refinements, the astute physician can make a fairly accurate estimate of the nature and extent of the damage even in the earliest stages. Armed with this knowledge he can foretell with some degree of certainty how the patient’s life must be regulated in order to prevent any worsening of the condition. A method of treatment that is unspectacular and miserably short of the ideal! Yet for all that it adds to many a patient’s life the boon of an extra five, 10, maybe even 20 years.

Drugs Can Help

Neither does it do to dismiss his drugs, because he has no miracle worker which will kill the germs of rheumatic heart disease as swiftly and surely as pencillin knocks out the germs of pneumonia. True enough, no drug yet discovered will stay the fundamental process underlying heart disease. But a miracle, or something very near a miracle, can be achieved in relieving the symptoms and complications arising from a heart which is on the brink of failure.

Oftentimes when the heart has been j strained by disease for a considerable period it breaks out from under the control of its “pacemaker.” When this happens its beat becomes as irregular as that of a gasoline engine with crossed ignition wires. Its futile sputterings, unless very soon controlled, lead to a complete breakdown of the circulation. Blood piles up in the veins behind the heart for just the same reason as a traffic snarl grows behind a road obstruction. The lungs become congested and the patient gasps for air 1

even as he lies in bed. Fluid seeps through the walls of bulging blood vessels and waterlogs the tissues. And it is just when the patient is in this pitiable condition that the physician can use his drugs to most spectacular advantage.

Digitalis of itself alone will usually snatch the patient from the jaws of death. Unaided it will, in almost every case, bring the heart hack to a sane and sensible rhythm, will add power to the heat, and drive the fluid from the waterlogged tissues into the kidneys from which it is excreted. And to aid digitalis in this work there are a half dozen other drugs which the physician can produce from the recesses of his bag, each of which will control one or other symptoms of heart failure. So complete can be the relief that many times a patient has been snatched from the edge of the grave in just this way and has lived to resume his normal * working life for another decade or more.

What prospects the future holds for development in the treatment of heart disease it would be hazardous to guess. The greatest medical discoveries of the past decade have practically all been in the control of the germ-caused diseases. Rheumatic heart disease, like pneumonia and septicemia, has its beginnings in bacterial infection, yet so far there has been no drug discovered which will for certain seek out and annihilate the organisms responsible. But science cannot be discouraged. In laboratories, scattered from one end of the earth to the other, biochemists are constantly concocting new germ-killing agents. It is all rather like searching for a particular key in a mountain of those elusive objects. Sooner or later someone must emerge in triumph, brandishing aloft i the implement that will unlock the door to health for victims of this disease.

With regard to the degenerative type of heart disease which is so common among the elderly, the problem is entirely different. Here there is no germ to be killed by some new miracle drug. The problem is the problem ot growing old itself. Paradoxically the sulfonamides, penicillin, insulin, liver extract, and the other lifesaving drugs indirectly aggravate the problem because they save the youthful and middle aged from earlier death and carry them safely into those later years in which this form of heart disease is so prevalent. Yet if the problem is a mighty one the reward is equally great, for its solution would mean the addition of years to our life expectancy. At this moment the eyes of the medical profession are turned toward Russia. There is a rumor that here has been prepared a serum which will postpone the ageing of human tissues. It seems incredible. It would not do to place reliance on it, but equally foolish would it be to discount it in advance. The Russians are a strange people. They have a way of backing their claims with achievement.