During the first half of the 19 century, several important contributions to the knowledge of the diseases of the heart were made by physicians working in Dublin. Brilliant internists such as Stokes, Graves, Corrigan and Cheyne constituted the famous Dublin School of Medicine.
William Stokes was one of the most respected physicians of the Dublin School. He had a great interest on cardiac auscultation using the stethoscope which was invented by Laennec in 1816. Stokes published the first book in the English language on auscultation in 1825. His second important work appeared under the title, "A treatise on the diagnosis and treatment of diseases of the chest," in 1837.
William Stokes associated his name with two disorders that he described.The first is Cheyne-Stokes respiration which is an abnormal pattern of breathing characterized by gradually deeper and occasionally quicker breathing, followed by a progressive decrease that could result in apnea. These episodes of hyperventilation and apnea occur in cycles that last from less than one minute to several minutes. The second is Adams-Stokes Syndrome which is characterized by a sudden transient episode of syncope with convulsive seizure caused by a rapid decrease in cardiac output due to heart block. His study on the latter topic was published in an article, "Observations on some cases of permanently slow pulse," in 1846. Both these conditions were extensively reviewed in his authoritative textbook, "The diseases of the heart and the aorta," which was published in 1854.
Throughout his career, William stokes developed a true expertise in valvular heart diseases. In his monograph, he gave excellent accounts of valvular heart diseases with description of clinical manifestations and postmortem examination. He stressed the importance of a murmur detected on auscultation in diagnosis of valvular disease.
The chapter of his monograph on mitral valve diseases is divided into 4 sections:
Symptoms of disease of the mitral valves
Physical signs of disease of the mitral valves
Combinations of disease of the mitral valves
Contraction of the mitral valves
Disease of the mitral valve without contraction
In the sections on symptoms and physical signs of mitral valve disease, Stokes confirmed the findings of previous authors. He also referred regularly to the work of Laennec, Hope and Adams in this chapter. Although Stokes stressed the importance of auscultation on physical diagnosis, he also cautioned against overreliance on this modality to make the diagnosis of organic valve disease.
He discussed several cases of double mitral and aortic valve diseases. He described the seat and characteristics of each murmur and emphasized the difficulty of diagnosis in this setting. This is a brief quotation from his comments on auscultation in double valve disease:
"...for the mitral valves may be so altered as that no murmur whatever shall be produced during the passage of blood through them; and again the murmur from the aortic opening may be so loud, and also propagated downwards into the ventricle, as to obscure the mitral murmur, even should it exist."
In the section on contraction of the mitral valves, Stokes provided a simplified and methodical analysis of the clinical manifestations as follows:
"1) General symptoms- Palpitations; Dyspnoea on exercise, occurring independently of pulmonary disease; cardiac pains.
2) Symptoms referrible to disease of the left side of the heart- Irregularity, rapidity, feebleness, and diminished volume of the pulse; syncope; haemoptysis; sudden death.
3) Symptoms referrible to disease of the right side- Venous turgescence; pulmonary congestion; pulsation of the jugular veins; varying enlargement of the liver; anasarca; want of proportion between the strength, and perhaps the rapidity of the action of the heart and pulse."
Regarding the discrepancy between the heart rate and the arterial pulse in mitral stenosis, Stokes made the following comments: "It must be admitted, that the real or apparent difference of rate between the impulse of the heart and that of the artery, as observed at the wrist, has not yet received sufficient investigation. As one of the symptoms of disease of the mitral valves, it is of great value; and a difference of not less than fifteen beats between the rate of the heart and pulse has been observed. Even a greater discrepancy may occur." He also noted that in these patients with rapid and irregular pulse, "the murmur becomes imperceptible or nearly so."
Finally, Stokes also discussed the distension and pulsation of the jugular veins in patients with mitral stenosis and referred extensively to the work of his predecessors such as Adams, Hunter, and Lancisi.
In the last section "on the disease of the mitral valve without contraction", Stokes described mitral annular dilatation as a cause of valvular regurgitation. In the discussion, he demonstrated a great understanding of the pathophysiology of this condition:
"In the case of the mitral valves, with an actually enlarged opening, the ventricle and auricle may be held to form one bilocular cavity, both portions of which have a mutual re-action.The auricle having become distended, and probably hypertrophied, by regurgitation from the ventricle, sends an increased quantity of blood into that cavity, which latter has to expend its force not only in the direction of the aorta, but also in that of the auricle; thus it becomes not only dilated but hypertrophied; yet as the quantity of blood propelled into the aorta must be reduced in proportion to the size not only of the auricle, but also to that of its orifice, we have produced those effects which result from a weakened ventricle, even when no valvular lesion exists, as in fatty degeneration of the left ventricle."
The entire text on the diseases of the mitral valve is displayed here.
In his monograph, Stokes also reported probably the first case of biventricular dilated cardiomyopathy with severe enlargement of atrioventricular orifices and valvular regurgitation. The patient was a 34 year old man who presented initially with cough, dyspnea and palpitation. He then developed clinical manifestations of congestive heart failure that led to his demise.
At postmortem examination, Stokes noted:
" The heart was found to be enlarged to more than twice its natural volume; this increase of size was principally owing to dilatation of the cavities. The right auriculo-ventricular opening admitted of five fingers being passed through it; its circumference measured six inches and a quarter.The valves were healthy, but evidently incompetent to close the orifice. The circumference of the pulmonary artery was not less than four inches; the valves healthy; four fingers could be passed through the left auriculo-ventricular opening; its valves were healthy, but its circumference measured five inches; the valves seemed insufficient to close the opening. The circumference of the aortic orifice was three inches and three quarters."
Following the autopsy reports, Stokes stressed that the clinical manifestations and physical signs were in favor of an organic heart disease. He then discussed the characteristics of cardiac murmurs in patients with multivalvular disease and the difficulty of the diagnosis. In his closing comments, Stokes noted:
"If we consider that in chronic disease of the heart, when it is attended with symptoms and disturbance of action, with visceral congestion and dropsy [heart failure] , there is generally a complicated condition; that more than one set of valves is probably engaged, even though the physical signs seem to point out that but a single set are affected; and reflect that it is not always the more important lesion that causes the most prominent physical sign; and that the signs of disease on one side of the heart may mask the natural phenomena on the other- we must be slow in giving a special or an exclusive diagnosis."
In his monograph, Stokes summarized his views on valvular heart disease point-by-point in a very interesting text which is displayed here.
Finally, Stokes described several cases of chordal rupture involving the mitral or tricuspid valve. These valvular lesions were reported in the section on "Rupture of the heart". In his text, He gave credit to Corvisart for describing the first case of mitral regurgitation with chordal rupture. For each case, he provided a detailed description of clinical manifestations and autopsy findings. His comments, however, added little to the knowledge on this topic.