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Adaptive and Maladaptive Hypertrophy: 18th & 19th Century Views Arnold M. Katz, MD, DMed (Hon.) Visiting Professor of Medicine and Physiology Dartmouth College Hanover, New Hampshire Professor of Medicine Emeritus University of Connecticut School of Medicine Farmington, Connecticut Heart Failure The 18th & 19th Centuries Clinical Picture Digitalis Architecture of the Failing Heart “Modern Echoes” Heart Failure in the 19th Century The respiration, always short, becomes hurried and laborious on the slightest exertion or mental emotion. The effort of ascending a staircase is particularly distressing. The patient stops abruptly, grasps at the first object that presents itself and fixing the upper extremities in order to afford a fulcrum for the muscles of respiration, gasps with an aspect of extreme distress. Incapable of lying down, he is seen for weeks, and even for months together, either reclining in the semi-erect posture supported by pillows, or sitting with the trunk bent forward and JAMES HOPE the elbows or fore-arms resting on the drawn-up Treatise on the Diseases knees. The latter position he assumes when of the Heart and Great Vessels (1832). attacked by a paroxysms of dyspnea - sometimes, however, extending the arms against the bed on either side, to afford a firmer fulcrum for the muscles of respiration. Heart Failure in the 19th Century With eyes widely expanded and starting, eye-brows raised, nostrils dilated, a ghastly and haggard countenance, and the head thrown back at every inspiration, he casts around a hurried, distracted look of horror, of anguish, of supplication: now imploring, in plaintive moans, or quick broken accents, and half-stifled voice, the assistance already often lavished in vain: now upbraiding the impotency of medicine; and now in an agony of despair, drooping his head on his chest, and muttering a fervent invocation for death to put a period to his sufferings. JAMES HOPE Treatise on the Diseases of the Heart and Great Vessels (1832). Heart Failure in the 19th Century For a few hours - perhaps only for a few minutes - he tastes an interval of delicious respite, which cheers him with the hope that the worst is over, and that his recovery is at hand. Soon that hope vanishes. From a slumber fraught with the horrors of a hideous dream, he starts up with a wild exclamation that “it is returning.” At length, after reiterated recurrences of the same attacks, the muscles of respiration, subdued by the efforts of which the instinct of self-preservation alone renders them capable, participate JAMES HOPE Treatise on the Diseases in the general exhaustion, and refuse of the Heart and Great Vessels. (1832) to perform their function. The patient gasps, sinks, and expires. Heart Failure The 18th & 19th Centuries Clinical Picture Digitalis Architecture of the Failing Heart Discovery of Digitalis (1785) “In the year 1775, my opinion was asked concerning a family recipe for the cure of the dropsy. I was told that it had long been kept a secret by an old woman of Shropshire, who had sometimes made cures after the more regular practitioners had failed… The medicine was composed of some twenty or more herbs; but it was not very difficult for one conversant with these subjects to perceive that the active herb could be no other than Foxglove.” William Withering An Account of the Foxglove and Some of its Medical Uses (1785). Digitalis purpura “[Digitalis] has a power over the motion of the heart, to a degree yet unobserved in any other medicine, [that] may be converted to salutary ends.” A Modern Echo (1997) Does Digitalis Improve Prognosis in Heart Failure Patients Who Are in Sinus Rhythm? Mortality From Any Cause (%) 50 40 30 20 Placebo 10 P=0.80 Digoxin 0 0 4 8 12 16 20 24 28 32 36 40 44 48 52 Months The Digitalis Investigation Group. N Engl J Med.1997;336:525-32. Heart Failure The 18th & 19th Centuries Clinical Picture Digitalis Architecture of the Failing Heart Architectural Patterns of Cardiac Enlargement Distinguished between enlarged hearts with increased cavity size (eccentric hypertrophy, dilatation), and with increased wall thickness (concentric hypertrophy, hypertrophy). JOANNIS MARIA LANCISI De Aneurysmatibus, (1728) “So varied and so serious are the maladies of the heart that we often discover that it has suffered from an increase in its own bulk, ’ combined with enlargement []. Nor do I mean here by increase of bulk dilatation of the cavities only, but thickening of the fibers and increase of density [that] makes the base of the heart heavier than is normal...” Architectural Patterns of Cardiac Enlargement It is necessary to distinguish two species of [cardiac enlargement]. In the first the heart is enlarged, its [walls] thickened, the energy of its action increased. Concentric Hypertrophy (“Hypertrophy”) J.N. CORVISART An Essay on the Organic Diseases and Lesions of the Heart and Great Vessels (1812). In the second there is likewise enlargement, but [also] thinning of the [walls] and diminution of energy in the action of the organ. Eccentric Hypertrophy (“Dilatation”) Architectural Patterns of Cardiac Enlargement Concentric Hypertrophy “Hypertrophy” Normal Eccentric Hypertrophy “Dilatation” Dilatation Weakens the Heart [That] the heart may be too big for its system is a melancholy fact; for when it becomes relaxed, it enlarges, and as it grows in bulk loses its power… JOHN BELL The Anatomy of the Human Body. 2nd Ed. (1802). Prognosis is Worse in Dilatation Than Hypertrophy …considered in the abstract, dilatation of the heart has the effect to weaken the contractile power of the muscular substance…The muscular fibres lose in strength what they acquire in extent. Réné-JosephHyacinthe Bertin Treatise on the Diseases of the Heart and Great Vessels (1833). …the progress of hypertrophy is, in general, slow, tardy and chronic… frequently hypertrophy does not merit on its own account anything more than a secondary consideration. Prognosis is Worse in Dilatation Than Hypertrophy Hypertrophy, by adding to the heart’s power… tends to maintain itself, while dilatation tends downwards. JOHN MILNER FOTHERGILL The Heart and Its Diseases. 2nd Ed. (1879). Dilatation is Progressive When dilatation has progressed so far as to occasion morbid dyspnea, it has a constant tendency to increase unless the circulation be kept tranquil by a very quiet life and judicious medical treatment. – JAMES HOPE A Treatise on the Diseases of the Heart and Great Vessels (1832). If the dilatation… [has] reached a certain degree, and so far as to induce a morbid dyspnoea, the disease has a marked tendency to increase, unless the circulation be maintained in a state of complete repose. – FRANCOIS ARAN Practical Manual of the Diseases of the Heart and Great Vessels (1843). A Modern Echo (1985) Effect of an ACE Inhibitor on “Remodeling” LV Pressure (mmHg) 30 Infarct, Placebo Infarct, ACEI Control – No infarct 20 10 0 0 0.6 1.2 1.8 2.4 3.0 LV Volume (ml/Kg) Pfeffer JM, Pfeffer MA & Braunwald E. Circ Res. 1985;57:84-95. Hypertrophy is Compensatory In [valvular heart disease], nature, to enable the heart to perform the additional labour thrown upon it, increases its strength by an addition of muscular fibre, and the heart thus becomes hypertrophied, in accordance with the general law, that muscular fibres become thickened and strengthened when there is additional power required from it. – DOMINIC JOHN CORRIGAN Edinburgh Med Surg J (1832). What is seen in the arm of blacksmiths, in the legs of dancers, is also seen in the heart… In proportion as the walls are thickened, its contractile power augments. – FRANCOIS ARAN Practical Manual of the Diseases of the Heart and Great Vessels (1843). A Modern Echo (1968) Hypertrophy is Compensatory 320 Normal (dynes/cm2 103) Stress x Pressure (dynes/cm2 x 103) Wall Thickness (mm) 160 120 80 20 40 10 Circumferential Stress – Pressure 240 200 Pressure Overload (Aortic Stenosis) 280 Wall Thickness Circumferential Stress – Pressure 280 240 Stress (dynes/cm2 x 103) Pressure (dynes/cm2 x 103) Wall Thickness (mm) 200 160 120 30 80 20 40 10 Wall Thickness 320 0 0 0 0.2 0.4 0.6 0.8 0 Time After Onset QRS (sec) 0.2 0.4 0.6 0.8 Time After Onset QRS (sec) Hood WP, Rackley CE & Rolett EL. Am J Cardiol. 1968;22:550-8. Hypertrophy Protects Against the Deleterious Effects of Dilatation [Overload] excites a more forcible ventricular action… and hypertrophy is produced. The increased muscular growth for a certain period protects against the occurrence of dilatation. At length, hypertrophy reaches a point beyond which it cannot advance… The causes, however, persist and… can produce only dilatation [so that] from this period the progressive enlargement is due to augmentation of the cavities… AUSTIN FLINT Diseases of the Heart 2nd Ed. (1870). According to this view, hypertrophy becomes an important conservative provision, first, against over-accumulation of blood, and second, against the more serious form of enlargement, viz., dilatation. Hypertrophy is Compensatory But Dilatation is Usually Deleterious Hypertrophy is a compensatory and beneficial condition, in fact, nature’s effort to meet a difficulty… Dilatat is the direct opposite of hypertrophy, inasmuch as it impairs the efficiency of the cardiac pump. BYROM BRAMWELL Diseases of the Heart and Thoracic Aorta (1884). …[although] dilatation is usually bad, in regurgitant valvular lesions dilatation of the cavity… behind the affected orifice is beneficial, providing that it is just sufficient to accommodate the blood which is regurgitated at each systole. Hypertrophy Can Be Deleterious As Well As Compensatory Hypertrophy [which] always occurs wherever a portion of the heart has been called upon to perform work beyond its normal capacity… may exist for many years, and the individual still continue to have relatively good health, but in the end it certainly leads to a so-called catastrophe through some of its sequels… which are of themselves full of danger to the patient. – LEOPOLD SCHROETTER Ziemssen’s Practice of Medicine (1876). It has frequently been said that the heart hypertrophies in order to establish a sort of compensation… This view would be correct if the hypertrophy remained stationary; but experience has shown that the excess of work imposed upon the heart finally deteriorates its fibres … – CONSTANTIN PAUL Diseases of the Heart (1884). A Modern Echo (1987-1988) -Myosin Heavy Chain -Tropomyosin Pressure overload Sham operated Fetal ventricle Pressure overload Sham operated Pressure overload Fetal ventricle -Myosin Heavy Chain Sham operated Fetal ventricle Hypertrophy is Accompanied by Reversion to the Fetal Phenotype Skeletal -Actin Izumo S et al. J Clin Invest. 1987;79:970. Izumo S et al. Proc Nat Acad Sci. USA. 1988;85:339. Adaptive and Maladaptive Hypertrophy Three Stages in the Heart’s Response to Overload 1) “DEVELOPMENT”: Depends on the nature of the underlying abnormality. 2) “FULL COMPENSATION”: Allows the heart’s “vigor” to meet the increased hemodynamic demand. (ADAPTIVE HYPERTROPHY) WILLIAM OSLER The Principles and Practice of Medicine (1892). 3) “BROKEN COMPENSATION”: Can result in acute dilatation [pulmonary edema], but more commonly evolves slowly as the result of “degeneration and weakening of the heart muscle.” (MALADAPTIVE HYPERTROPHY) Hypertrophy and Dilatation Result from Different Mechanical Stresses …in obstruction… without any increase in the distending force, as in aortic stenosis, there is pure hypertrophy, usually without dilatation. Increased Systolic Stress With increase in the distending force [as in aortic insufficiency], hypertrophy is always combined with dilatation of the cardiac chambers. JOHN MILNER FOTHERGILL The Heart and Its Diseases. 2nd Ed. (1879). Increased Diastolic Stress Hypertrophy and Dilatation Result from Different Mechanical Stresses Aortic stenosis (Hypertrophy) Increased Systolic Stress Aortic insufficiency (Dilatation) Increased Diastolic Stress A Modern Echo (2001) Systolic and Diastolic Stress Activate Different Signaling Pathways Strain Pacing Strain imposed during the systolic phase Strain imposed during the diastolic phase MEK1/2 Strain imposed during systolic phase Strain imposed during diastolic phase 11 10 9 8 7 6 5 4 3 2 1 0 10 Phosphorylation of MEK1/2 (Fold basal) Phosphorylation of p44/42 MAPK (Fold basal) P44/42 MAPK Strain imposed during systolic phase Strain imposed during diastolic phase 9 8 7 6 5 4 3 2 1 0 0 10 20 30 40 Time (min) 50 60 0 10 20 30 40 50 60 Time (min) Yamamoto K et al. Circulation. 2001:103:1459-64. Heart Failure The 18th & 19th Centuries Clinical Picture Digitalis Architecture of the Failing Heart “Modern Echoes”