Chapter 279 - Heart Failure: Pathophysiology and Diagnosis Flashcards
How prevalent is heart failure in developped countries?
2% regarding global population. It increases with age, affecting 6-10% of people over 65 years of age.
How do you explain that almost half of the patients with heart failure are women, although this clinical syndrome is relatively less common in comparison to men?
“Although the relative incidence of Heart Failure (HF) is lower in women than in men, women constitue at least one-half of the cases of HF because of their longer life expectancy.”
Normal or preserved ejection fraction heart failure affects approximately one-half of the patients with heart failure syndrome.
True or False?
True.
What is the most frequent etiology for heart failure in developped countries?
Coronary artery disease (60-75%), aggravated by hypertension (75%).
Name two toxic causes of dilated cardiomiopathy.
Alcohol and chemotherapy.
It is known that an increasing number of cases of dilated cardiomiopathy are due to genetic defects affecting the cytoskeleton.
True or False?
True.
Cytoskeleton’s proteins mutations are associated with various hypertrophic aswell as dilated cardiomyopathy.
High output diseases usually cause heart failure in structurally healthy hearts.
True or False?
False.
Name mutations associated with dilated cardiomiopathy. How are these syndromes inheredited?
“Most forms of familial dilated cardiomyopathy are secondary to specific genetic defects, most notably those in the cytoskeleton. Most forms of familial dilated cardiomyopathy are inherited in an autossomal dominant fashion. Mutations of genes that encode cytoskeletal proteins (desmin, cardiac myosin, vinculin) and nuclear membrane proteins (laminin) have been identified thus far. Dilated cardiomyopathy also is associated with Duchenne’s, Becker’s, and limb-girdle muscular dystrophies.”
Name three causes of premature atherosclerosis.
Hypothyroidism, Hyperhomocysteinemia and Pseudoxantoma elasticum.
What is the most frequent cause of heart failure in south America?
Chagas’ disease.
What is the mortality rate in a patient with class I functional classification (NYHA) heart failure in comparison to a patient with class IV (NYHA)?
5-10% instead of 30-70%, respectively.
Symptomatic heart failure (HF) has a poor prognosis.
True or False?
True.
“Community-based studies indicate that 30-40% of patiensts die within 1 year of diagnosis and 60-70% die within 5 years, mainly from worsening HF or as a sudden event (probably because of a ventricular arrythmia.”
How come patients with heart failure (HF) might be asymptomatic for years?
“one potential explanation is that a number of compensatory mechanisms become activated in the presence of cardiac injury and/or left ventricular (LV) dysfunction allowing patients to sustain and modulate LV function for a period of months to years. The compensatory mechanisms that ahve been described thus far include (1) activation of the renin-angiotensin-aldosteron (RAA) and adrenergic nervous systems, which are responsible, respectively, for maintaning cardiac output through increased retention of salt and water, and (2) increased myocardial contractility.”
What might explain the transition from asympatomatic to symptomatic heart failure (HF)?
“Although the exact mechanisms that are responsible for this transition are not known (…), the transition to symptomatic HF is acocompanied by increasing activation of neurohormonal, adrenergic, and cytoine systems that lead to a series of adaptive changes within the myocardium collectively referred to as LV remodeling.”
The pathogenesis of heart failure (HF) with preserved ejection fraction (HFpEF) is related to diastolic dysfunction, aswell as additional extracardiac mechanisms (such as increased vascular stiffness and impaired renal function).
True or False?
True.
Name the main events that lead to left ventricle (LV) remodeling.
“LV remodling develops in response to a series of complex events that occur at the cellular and molecular levels. These changes include (1) myocyte hypertrophy; (2) alterations in the contractile properties of the myocyte; (3) progressive loss of myocytes through necrosis, apoptosis, and autophagic cell death; (4) beta-adrenergic desensitization; (5) abnormal myocardial energetics and metabolism; and (6) reorganization of the extracellular matrix with dissolution of the organized structural collagen weave surrounding myocytes and subsequent replacement by an interstitial collagen matrix that does not provide structual support to the myocytes.”
Name the biologic stimuli for the left ventricle remodeling.
“The biologic stimuli for these profound changes include mechanical stretch of the myocyte, circulating neurohormones (e.g., norepinephrine, angiotensin I), inflammatory cytokines (e.g., tumor necrosis factor [TNF]), other peptides and growth factors (e.g., endothelin), and reactive oxygen species (e.g., superoxide).”
How do you explain higher concentrations of citosolic calcium in heart failure myocytes?
“The changes that regulate excitation-contraction include decreased function of sarcoplasmic reticulum Ca2+ adenosine triphosphatase (SERCA2A), resulting in decreased calcium uptake into the sarcplasmic reticulum (SR), and hyperphosphorylation of the ryanodine receptor, leading to calcium leakage from the SR.”
