Letters to the Editor

Exercise--hazard or health aid

To the Editor: The idea tha t one type of exercise is beneficial and another

harmful may appear mystical to Dr. Eskwith 1 bu t there is scientific evidence this may be true.

I refer you to Dr. Joel Morganroth 's report on two types of athletic heart2: the diastolic hear t of the distance runner and the systolic heart of the weightlifter and shotputter .

We distance runners natural ly look on the diastolic hear t as the one to have. But then we do tend to be mystics.

George A. Sheehan, M.D. 79 Wes t Front St.

Red Bank, N. J. 07701

REFERENCES 1. Eskwith, I. S.: Reply (Letter to Editor), Am. Heart J.

92:267, 1976. 2. Morganroth, J., et al.: Comparative left ventricular

dimensions in trained athletes, Ann. Intern. Med. 82:521, 1975.

What kind of evidence?

To the Editor: In the August, 1976, issue of the JOURNAL Eskwith, 1 in reply

to a letter, writes the following: "Circumstantial evidence, no mat ter how strong, has no place in scientific discipline and cannot be substi tuted for proof, neither can anecdotal reports. ''1 He considers his correspondent's contention tha t one type of exercise can be beneficial, another harmful, "too mystic a concept" to be believable. In this connection it may be useful to ask, what kind of evidence is acceptable to science?

I t is clear tha t data can be misinterpreted and medicine, like any other branch of science, provides ample scope for human error. Equally clearly, generalizations and hypotheses should be carefully scrutinized before they gain acceptance. As there is only one basic faculty of human reasoning, the scientist has no other mental equipment at his disposal than anyone else. He differs only in the more disciplined use of this faculty, imposed on him by more rigorous criteria of what constitutes acceptable evidence of validity.

Generalizations based on a few examples, to which the vogue term "anecdotal" presumably applies, belong to the genus of statistics derived from an insufficient number of samples. They can doubtless be sources of error. An amusing example is cited by Gordon, 2 writing of a Russian report to the effect tha t the incidence of heart disease was higher among the staff of a Moscow Inst i tute of Food than in an Ins t i tu te of Geology.

While on the subject of possible sources of error, may I mention another example? This is the often ignored uncer- tainty, when the results of animal trials are applied to human practice. An example is the classic experiment in 1913 of Anitchkow and Chalatow, who were the first to produce atheroma-like lesions in cholesterol-fed rabbits. The source of

error in this case is t ha t some mammals, including man, possess a mechanism regulating the absorption of dietarY cholesterol, enabling them to reject excess intake Undigested, while some herbivores, like rabbits, do not. The presumable reason is tha t plants contain lit t le cholesterol, so t h a t ' t h e ingestion of a quant i ty in excess of needs is so unlikely for a herbivore under na tura l conditions, tha t a mechanism capable of rejecting such excesses has no survival value for them. The lack of this information in the earlier decades of the present century has led to the ill-founded but widely accepted belief tha t excess cholesterol in the diet was the main cause of human atheroma.

However, it is possible to err in two directions. In science, insistence on too rigorous criteria of validity can have a stifling effect. Non-communicable diseases, like cancer, athe- roma or multiple sclerosis, seldom oblige us by providing easily recognizable clues for their etiology and pathogenesis, so who is to provide those perfect, incontrovertible, scientifically acceptable hypotheses? Since beginnings have to be made somewhere, most probably imperfect beginnings, is it not the case of cutting our coats to fit our cloth? Insistence on perfection is likely to result in scientists refraining from at tempting the impossible and keeping to data-collecting and fact-finding.

The worst example in this respect is cancer research, with its flood of li terature on experiments with inbred, x-ray irra- diated, cortisone-treated rats. Most of these experiments are probably irrelevant to any aspect of human cancer and most are probably of the nature of trying to find out how a motorcar worked by experimenting on it, e.g., by drilling holes in its hood or by mixing chicken blood with its gasoline. While such experiments are impeccably scientific in form, they are utterly sterile and unproductive in practice. Perhaps the best judgment on them, to quote Gordon again: "seldom can so much have been writ ten by so many and read by so few. ''2

In my opinion the only practicable criterion of validity ever produced by science is tha t of consistency. A deduction or generalization derived from one set of data is tentat ively regarded valid if it is consistent with similar deductions or generalizations based on another set of data and is finally incorporated in the tenets of science unless later challenged by new observations. This is how science does, in fact, progress. The progress may be halt ing and jerky, but, in the long run, it is progress.

Let us consider, how all this applies to the subject of Dr. Eskwith's letter. In my opinion any evidence relevant to a problem is admissible and cannot be rejected by catchwords like "circumstant ia l" or "anecdotal." The replier should take the trouble to explain why a thesis is unacceptable, t ha t is, provide data which contradict it or with which the thesis is inconsistent.

I do not agree tha t the proposition t ha t some exercise can be beneficial, other harmful, is obviously wrong. Sudden bursts of violent exercise could be harmful, because they are likely to find any weakness of the circulatory system. Sedentary life can conceivably be harmful because never used capillaries and arterioles may disappear, which may mean the difference between death and survival in an emergency following the

A m e r i c a n H e a r t J o u r n a l 5 3 7

Letters to the Editor

occlusion of an artery in the coronary circulation. Moderate, regular exercise may steer a median course between the two evils.

Stephen Seely, B.Sc. 3 Truro Drive, Sale, Cheshire

M33 5DF, England

REFERENCES 1. Eskwith, I. S.: Reply (Letter to Editor), AM. HEART J.

92:267, 1976. 2. Gordon, I.: Cholesterophobia, 1962, Medical Officer,

108:385, 1962.

Reply

To the Editor: I now find myself answering letters writ ten to the reply of

my original communication to your JOURNAL. In reference to Doctor Sheehan's letter, perhaps long distance runners have a lower mortali ty from hear t disease, perhaps not. They form a very small group. Regardless of what their mortal i ty is, I can ' t see the general population getting up every morning and running twenty miles before reporting to work. I don ' t think we should be too sanguine about this small group of people until more data have been compiled on them.

Doctor Seely's letter is most interesting. To my mind, objective evidence in connection with atherosclerotic heart disease would be the application of a remedy which by itself produces a sharp and sustained reduction in mortal i ty from heart disease. An example of such objective evidence would be the mortali ty from subacute bacterial endocarditis prior to the use of penicillin therapy and afterwards. Koch's Postu- lates still remain excellent guidelines for determining what objective criteria are. I t is apparently not considered stylish to read them anymore, but I think we all should, for they are as valid today as when they were originally written. These furnish a good skeleton on which to construct any experiment tha t would have in mind the reduction of hear t disease.

Naturally, as a writer, even of a letter, I have been very pleased at the response my original note has elicited. Ventila- tion of controversy, particularly in areas tha t are themselves controversial, is always beneficial and stimulating.

Irwin S. Eskwith, M.D. Pinnell Street

Ripley, W. Va. 25271

The simultaneous occurrence of a ventricular septal defect and mitral insufficiency after myocardial infarction

To the Editor: It is of interest to note the rari ty of simultaneous

occurrence of ventricular septal defect and mitral regurgita- tion complicating myocardial infarction. Doctors Gowda, Loh, and Roberts (AM. HEART J. 92:234, 1976) remarked "it is possible tha t surgery may be helpful when both lesions are present, if recovery is possible for 2 to 3 weeks." The following report demonstrates the success of surgery in such a case.

Case report A 6!-year-old white male was admitted to the coronary care

unit of the V. A. Hospital, Salem, Va., on April 2, 1974, with the complaints of shortness of breath and ankle swelling. He

had been in his usual good heal th until two weeks prior to his admission when he developed vague chest pain and shortness of breath. He consulted his family physician who prescribed some medicine but his symptoms continued to get worse and he had shortness of breath on mild activity,, orthopnea, paroxysmal nocturnal dyspnea, and swelling of his legs at the time of admission to the V. A. Hospital. He smoked one pack of cigarettes per day and had some cough and mild dyspnea of effort in the past. He did not have hypertension, diabetes mellitus, or angina pectoris. His only previous admission to the hospital was in 1973 for bunionectomy.

Physical examination revealed an ill-looking man in respi- ratory discomfort. His pulse was 100' per minute in regular rhythm. Blood pressure was 95/50 mm. Hg. The neck veins were distended up to the angle of jaw with prominent "V" waves at 45 degrees inclination. The point of maximal impulse of the hear t was in the anterior axillary line in the fifth left intercostal space (LICS). No thrills were palpable. There was a summation gallop, pericardial friction ~rub, and 3/6 pansys- tolic murmur. The murmur was heard maximally in the fourth LICS along the parasternal border but radiated to the apex and the axilla. Bibasilar rfiles were present up to the angle of the scapulae. The liver was tender and was enlarged two fingerbreadths below the costal margin. There was pit t ing edema of the lower legs and sacral area. X-ray of the chest showed cardiomegaly, congestion of pulmonary vessels, and left ventricular failure. The electrocardiogram revealed regular sinus rhy thm with Q wave, ST elevation, and T wave inversion in Leads 2, 3, aVF and T wave inversion in Leads V~_8. Laboratory findings were: SGOT 345 units, SLDH 1096 units, and CPK 21 units. Hematocri t was 37 per cent and white blood cell count 7800/mm2 He was treated with intravenous furosemide, salt and fluid restriction, and digoxin. He had a good diuretic response and had subjective and objective improvement, but 36 hours after admission he became cyanotic and had no palpable pulses. He remained in sinus rhythm. Cardiopulmonary resuscitation was immedi- ately initiated and pericardiocentesis was a t tempted but did not yield any fluid. Norepinephrine infusion raised the systolic blood pressure to 100 mm. Hg and One hour la ter he was able to maintain blood pressure on his own. He was transferred to the University of Virginia Medical Center, Charlottesville, Virginia. Cardiac catheterization and coronary angiography were performed. These showed elevated r ight atrial pressure with "a" waves of 11, "v" waves of 12, and a mean pressure of 9 mm. Hg. Right ventricular and pulmonary ar tery pressures were 40/11 and 40/16 mm. Hg, respectively. Pulmonary capillary wedge pressure was also elevated and showed "a" and "v" waves of 16 and 21 mm. Hg. The re was a positive hydrogen curve in the pulmonary artery. Pulmonary-to- systemic blood flow ratio was 1.3 and a left-to-right shunt of 0.64 L. /min. /M. ~ Left ventricular end-diastolic pressure was elevated at 22 mm. Hg. Left ventricular angiography showed 2 to 3+ mitral regurgitation, akinesis of a large portion of inferior wall, and a discreet inferior wall aneurysm just beneath the posterior medial papillary muscle. Right coronary artery (RCA) cineangiography revealed the RCA to be the dominant coronary artery with complete occlusion in its proximal portion. Both left anterior descending and left circumflex coronary arteries showed 50 per cent occlusion with poor distal vessels. The next day he developed Mobitz II heart block and a temporary t ransvenous pacemaker was inserted.

5 3 8 October, 1977, Vol. 94, No. 4