The Effect of Acetylcholine on Pulmonary Vascular Resistance and Left Atrial Pressure in Mitral Stenosis

Title page reproduced by permission from the British Heart Journal 19:279, 1957.

July 25, 1972 The American Journal of CARDIOLOGY Volume 60 167

Commentary by Malcolm K. Towers, MD, MRCP

My own association with Dr. Paul Wood began in January 1955. The first edition of Diseases of the Heart and Circulation had appeared in 1950. I found it inspiring and determined to work for him. Supported by my teacher, Dr. William Evans of the London Hospital, I was able to get a job as lecturer at the Institute of Cardiology at the second or third attempt. Over the years I was promoted to senior lecturer and then was given a consultant post at the Brompton Hospital, begin- ning in July 1962, with the intention that I should work in the catheter laboratory there and continue my association with Wood. I think that any ap- preciation of his work ought to make reference to his book. Certainly he felt he had a great duty to keep it up to date, and he was working on the third edition when he died. If I remember correctly he died on Friday July 15, and he was working at the Brompton Hospital on the preceding Tuesday. I had cleared up a good deal of the routine work be- fore he arrived and he seemed very pleased and said, “At this rate I shall finish the book by Christ- mas.”

Wood’s greatest gift to his junior staff was the instruction and inspiration he gave them. We re- member his Tuesday afternoon clinic at the Heart Hospital. He arrived about 2 :30 PM usually com- plaining about the traffic or the difficulty in park- ing and having done a round at the Brompton Hospital that morning. The new patients (often twelve or fifteen of them) would have had their histories taken and been examined by one of his two senior assistants. The X-ray films and electro- cardiograms were done. When Wood arrived the assistants would present their cases in turn. He would check the history and always check the physical signs carefully himself. Anything which could not be directly quantitated (like the blood pressure, the pulse rate and the venous pressure) was graded 1 to 4 according to whether it was mild, moderate, considerable or gross. Similarly the heart sounds and murmurs were graded 1 to 4 for intensity and, in the case of diastolic murmurs, duration. With practice I found that I could write the grade down before he arrived and rarely had to alter a single grade in the afternoon. There were always many students, and he found time to ask them searching questions about the patient. The diagnosis was made from the history and the physical signs, and we would predict what the X-ray films and electrocardiogram ought to show. If they did not match, then every item in the his- tory and physical signs had to be checked. If the

diagnosis was still in doubt, then the points for and against the various diagnostic possibilities would be written down and considered. Wood us- ually left the clinic and his exhausted assistants between 5 and 6 PM and went off to see still more patients. He would get home between 8 and 9 in the evening and, having relaxed over a drink and his dinner, would start work on the book until the early hours of the morning. The next day his ob- servations on the clinic patients were carefully re- corded on indexed cards, and it was from these cards that he could make the statement in his book, “in a series of 400 cases analysed by the author. . . .” It is true that the clinical observations were often supported by special techniques such as phonocardiography and cardiac catheterization, but in the main they were clinical observations. The heritage which Paul Wood gave to his disciples was the technique of history taking and physical examination, the integration of this evidence with radiography, electrocardiography and other spe- cial techniques and the logical assessment of the whole situation. His pupils not only were able to deal with current problems but had been given the equipment to solve cardiological problems which could arise in the future.

From time to time there were Clinico-Patho- logical Conferences at the National Heart Hos- pital which were attended by distinguished visi- tors both from this country and overseas. Almost always Paul Wood dominated these meetings. He seemed to be able to assimilate the information more quickly and to put it into a logical pattern. Indeed at this distance in time it is hard to appre- ciate the extent of his dominance in cardiology in this country and in bedside cardiology throughout the world.

He would never tolerate careless work or care- less thinking. If one made a foolish statement he would pursue it to its logical conclusion and reduce it to absurdity. Some found this method of learn- ing too traumatic, but there was never any per- sonal malice in it. Although he would become heated in argument, some believed that he was not a particularly warm or emotional person. I do not myself think that this was true although I think it was a side of himself which he liked to keep hidden and usually did.

Acetylcholine and pulmonary vascular resis- tance : His work on the effect of acetylcholine on pulmonary vascular resistance in mitral stenosis might seem a little academic, but it had great clini- cal relevance. Paul Wood was much interested in

166 July 25, 1972 The American Journal of CARDIOLOGY Volume 30

patients with mitral valve disease who had a high pulmonary vascular resistance and often spoke of the difficulty of diagnosing mitral stenosis in this situation and how easily the diagnosis might be missed. There was considerable argument whether mitral valvotomy might be justified in such pa- tients because it was thought that the rise in pul- monary vascular resistance might not be reversi- ble. Wood demonstrated that the resistance was less fixed than had been supposed and as surgery has progressed to open valvotomy and valve re- placements using inverted aortic homograft, it has been confirmed that substantial falls in the pulmonary vascular resistance can occur even when the resistance has been very high. His ar- ticles on the Eisenmenger syndrome based upon lectures to the Royal College of Physicians were a remarkable achievement. Even the collection of

so many cases was a considerable feat. I well re- member how excited he was as he realized that the Eisenmenger syndrome occurred only with large communications in the case of ventricular septal defect and patent ductus arteriosus. I also remember, as he went through his figures, how fascinated he was to discover that the Einsen- menger syndrome in atria1 septal defect did not appear in children but mainly in women in middle life. He was later able to link this with observa- tions on the way in which the pulmonary vascular resistance normally fell after birth. So complete and comprehensive were his observations in 1958 that comparatively little new information has emerged since. His work was based on matchless and painstaking clinical observation, a sound knowledge of physiology in health and disease and an endlessly enquiring and agile mind.

Dr. Towers is Consulting Cardiologist, Harefield General Hospital, Hare- field, Middlesex, England.

July 25. 1972 The American Journal of CARDIOLOGY Volume 30 169