Peter Mere Latham was a prominent British physician and medical educator of the mid 19th century. He studied at Oxford University and obtained his medical degree in 1814.
He published his work, "Lectures on subjects connected with clinical medicine comprising diseases of the heart," in 1845-1846. In the preface of his book, Latham made the following comments regarding James Hope's treatise which was published in 1832 and reedited several times in less than one decade:
"The treatise of Dr. Hope is very comprehensive. It embraces all that concerns the heart, its physiology, its pathology, and the treatment of its diseases. But the very abundance of its matter has made it a hard book to the student, and its style, which is too often controversial, and even disputatious, repels many readers, and has been in some measure a hindrance to its usefulness."
He then continued regarding his own book: "Mine is a limited purpose. It is to regard the diseases of the heart only in one point of view, i.e. as they appear in the living man. But this one point of view includes the several objects of their clinical diagnosis, and their clinical history, and their medical treatment."
Latham stressed the importance of physical examination for the diagnosis of cardiac diseases. He was one of the early supporters of cardiac auscultation and contributed significantly to the widespread use of this diagnostic modality in England. Multiple chapters in his book are devoted to auscultation dealing with the origin of heart sounds and cardiac murmurs.
Similar to his contemporaries, Latham was uncertain about the origin of the first cardiac sound:
"...About the efficient cause of the first normal and natural sound of the heart there is, I am afraid, a good deal still in debate. After many direct experiments still physiologists do not agree. Pathologists and physicians then may well be pardoned any doubts and difficulties they may have about sounds which are abnormal and unnatural...It is very plausibly conjectured that the efficient cause of the first sound is pretty equally shared between the muscular structure of the ventricles and the auriculo-ventricular valves, and that both, by conditions under which they are placed during the systole, directly contribute to it..."
Latham was, however, convinced that the second heart sound was due to the closure of semilunar valves:
"...The efficient cause of the second sound of the heart admits of little doubt. Though it takes place during the diastole of the heart, yet is it in no way produced by the alterations of form and consistence which the ventricles then undergo. Their relapse from a state of tension to a state of flaccidity has nothing to do with it; but the second sound of the heart results simply from the sudden closure of the sigmoid valves by the recoil of the blood, when it is thrown back upon them from the pulmonary artery and the aorta."
Regarding cardiac murmurs resulting from mitral valve disease, Latham described clearly the systolic murmur of mitral regurgitation:
"...The same systole of the ventricle which carries the blood forward into the aorta, without impediment and without a murmur, where there is no disease, throws it back partially, and with a murmur , into the auricle, through the half-closed mitral orifice, which now admits its regurgitation."
Latham, however, expressed difficulty in identifying the diastolic murmur of mitral stenosis:
"...Yet the condition of disease in mitral valve is often found to be such as must have raised certain impediment to the passage of blood from the auricle into the ventricle. Why, then, is the murmur, which would indicate such impediment, and which would be coincident with the diastole of the heart, a thing not found in practice, when the mitral valve alone is diseased?"
Latham's book included several chapters dealing with the inflammation of the heart and valvular lesions resulting from rheumatism. He used the term endocarditis, introduced first by Bouillaud, extensively throughout his work. From 1836 to 1840, Latham took care of 136 patients with acute rheumatism at St. Bartholomew's Hospital. Ninety patients (47 males and 43 females) presented with cardiac manifestations (rheumatic endocarditis 63 patients, pericarditis 7 patients, endocarditis and pericarditis 11 patients, and doubtful cases 9 patients). Only three of these patients died during their hospitalization. Latham was of the opinion that early diagnosis and treatment of rheumatic endocarditis could potentially lead to cure although he recognized the possibility of relapse. He also expressed concern about the long term outcomes of patients with damaged valves:
"...Thus, while inflammation arrested and life saved in all the cases which occurred, even 63 in number, do indeed sufficiently testify how small is the present peril of life from rheumatic endocarditis, yet the entire restoration of the endocardium to its perfect structure in 17 only, and the permanent injury done to it in 46, denote a most fearful disease in regard to its distant results."
He then continued: "...Sad, indeed, but most interesting and instructive, would be the entire history of the lives and deaths of all those in whom I here witnessed the first attack of disease, which spoiled the perfect structure of the heart. Such an entire history I shall never know. I may learn a few particulars of one or two whom I may chance to meet with, and this is all I expect."
Latham treated patients with rheumatic carditis with blood-letting. This treatment was highly recommended by Jean Baptiste Bouillaud. Latham did not report any mortality with this treatment whereas Bouillaud had a high mortality following blood-letting as he was performing heavy and repeated episodes in his practice. Latham also used opium and mercury as an inflammatory agent for the treatment of this condition.
Two additional chapters of Latham's work are displayed here: