Tratado De Cardiologia Braunwald Pdf 15
Tianna Faure
Among the functional categories of cardiomyopathy (dilated, hypertrophic, and restrictive), restrictive is the least common33 Libby P, Bonow RO, Mann DL, Zipes DP (eds). Braunwald: tratado de doenças cardiovasculares. 9a. ed. Philadelphia: Saunders/Elsevier; 2013.. It is defined as a disease of the heart muscle that negatively impacts ventricular filling, with normal or reduced diastolic volumes or diminished in one or both ventricles. Ventricular function remains unchanged, at least early during the condition, and ventricular wall thickness tends to be normal or increased according to the underlying disease22 Kushwaha SS, Fallon JT, Fuster V. Restrictive cardiomyopathy. N Engl J Med. 1997;336(4):267-76..
The principal pathophysiological finding in restrictive cardiomyopathies (CMP) is diastolic dysfunction. Restricted ventricular filling occurs due to increased filling pressures and loss of ventricular compliance caused by excessive stiffening of the ventricular walls. This change is the result of myocardial fibrosis, inflammation or scarring33 Libby P, Bonow RO, Mann DL, Zipes DP (eds). Braunwald: tratado de doenças cardiovasculares. 9a. ed. Philadelphia: Saunders/Elsevier; 2013..
Clinical manifestations can be either right or left HF, because both ventricles may be affected. In the right ventricular involvement, signs of right-side HF predominated with elevated jugular venous pressure, peripheral edema, and ascites33 Libby P, Bonow RO, Mann DL, Zipes DP (eds). Braunwald: tratado de doenças cardiovasculares. 9a. ed. Philadelphia: Saunders/Elsevier; 2013.. When the left ventricle was affected, effort dyspnea was present and chest X ray showed lung congestion. It should be noted that the heart area was preserved in radiography, as there was no ventricular dilatation22 Kushwaha SS, Fallon JT, Fuster V. Restrictive cardiomyopathy. N Engl J Med. 1997;336(4):267-76..
Atrial dilatation is very common; the ventricular thickness may be normal or increased, diastolic volume may be normal or reduced, and myocardial relaxation is affected33 Libby P, Bonow RO, Mann DL, Zipes DP (eds). Braunwald: tratado de doenças cardiovasculares. 9a. ed. Philadelphia: Saunders/Elsevier; 2013.. A diagnosis of restrictive CMP should be expected when there is clinical HF syndrome associated with normal cardiac area and preserved systolic function44 Salemi V, Fernandes F, Nastari L, Mady C. Cardiomiopatias restritivas. In: Mesquita ET et al. Insuficiência cardíaca com fração de ejeção normal. São Paulo: Atheneu; 2009 .p.197-211. Ventricular filling basically depends on the pressure gradient between the atria and ventricle44 Salemi V, Fernandes F, Nastari L, Mady C. Cardiomiopatias restritivas. In: Mesquita ET et al. Insuficiência cardíaca com fração de ejeção normal. São Paulo: Atheneu; 2009 .p.197-211. At the beginning of diastole, ventricular filling depends on the atrial pressure, which is increased. In the late phase of diastole, atrial contraction and ventricular compliance are the main determinants44 Salemi V, Fernandes F, Nastari L, Mady C. Cardiomiopatias restritivas. In: Mesquita ET et al. Insuficiência cardíaca com fração de ejeção normal. São Paulo: Atheneu; 2009 .p.197-211.
Differential diagnosis of restrictive cardiomyopathies is conducted with constrictive pericarditis, which is considered a classic clinical challenge and one with significant implications for therapeutic conduct.33 Libby P, Bonow RO, Mann DL, Zipes DP (eds). Braunwald: tratado de doenças cardiovasculares. 9a. ed. Philadelphia: Saunders/Elsevier; 2013. Both conditions lead to rapid and deep decline in ventricular pressure at the beginning of diastole, with rapid increase in early diastole until it reaches a plateau, leading to a hemodynamic pattern known as the square root sign observed in the atrial pressure curves33 Libby P, Bonow RO, Mann DL, Zipes DP (eds). Braunwald: tratado de doenças cardiovasculares. 9a. ed. Philadelphia: Saunders/Elsevier; 2013.. In constrictive pericarditis, there is equalization of the diastolic pressures, whereas in restrictive cardiomyopathy, pressures may vary more than 5 mmHg.
The most common specific cause of restrictive cardiomyopathy is amyloidosis; in almost half of cases, restrictive cardiomyopathy may be idiopathic. Amyloidosis is a generally progressive infiltrative systemic disease.33 Libby P, Bonow RO, Mann DL, Zipes DP (eds). Braunwald: tratado de doenças cardiovasculares. 9a. ed. Philadelphia: Saunders/Elsevier; 2013. In its cardiac form, amyloid protein is deposited in the myocardium and can result in restrictive cardiomyopathy, systolic HF, orthostatic hypotension, or conduction system disturbances33 Libby P, Bonow RO, Mann DL, Zipes DP (eds). Braunwald: tratado de doenças cardiovasculares. 9a. ed. Philadelphia: Saunders/Elsevier; 2013.. The ECG is greatly valuable in confirming the diagnosis, diffusely showing low QRS voltage complexes that, along with the thickened appearance of the ventricular walls in the echocardiogram, strongly suggest an infiltrative disease33 Libby P, Bonow RO, Mann DL, Zipes DP (eds). Braunwald: tratado de doenças cardiovasculares. 9a. ed. Philadelphia: Saunders/Elsevier; 2013..
With respect to the treatment, measures to control symptoms related to diastolic HF should be implemented, such as volemic control. Diuretics and vasodilators should be used with caution because these patients' cardiac output is largely dependent on the increased venous pressures44 Salemi V, Fernandes F, Nastari L, Mady C. Cardiomiopatias restritivas. In: Mesquita ET et al. Insuficiência cardíaca com fração de ejeção normal. São Paulo: Atheneu; 2009 .p.197-211. Digoxin and calcium channel blockers should be avoided because they may bind to the amyloid substance and cause toxicity44 Salemi V, Fernandes F, Nastari L, Mady C. Cardiomiopatias restritivas. In: Mesquita ET et al. Insuficiência cardíaca com fração de ejeção normal. São Paulo: Atheneu; 2009 .p.197-211. A specific treatment must be determined on the basis of the etiology of amyloidosis. In its primary form (AL), alkylating chemotherapy can be used with or without concomitant use of autologous bone marrow transplant. The average survival of patients with cardiac amyloidosis is estimated to be 5 months44 Salemi V, Fernandes F, Nastari L, Mady C. Cardiomiopatias restritivas. In: Mesquita ET et al. Insuficiência cardíaca com fração de ejeção normal. São Paulo: Atheneu; 2009 .p.197-211. Heart transplant should be considered, but with a possibility of relapse in a short time and with survival rates of 30% for 5 years33 Libby P, Bonow RO, Mann DL, Zipes DP (eds). Braunwald: tratado de doenças cardiovasculares. 9a. ed. Philadelphia: Saunders/Elsevier; 2013..
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