Cardiovascular II Flashcards
What are the 6 principle mechanisms of heart disease?
Failure at the pump Flow obstruction Shunted flow "Leaky" flow (bad valves) Canduction disordes Rupture of heart/major vessel
Congestive Heart Failure definition
Failure of the heart to pump an adequate amount of blood to supply the metabolic requirements of the organs
Is Congestive heart failure due to pathologic conditions inside or outside of the heart?
It may be due to either
What are the compensatory mechanisms of congestive heart failure?
The heart can compensate to try and keep pace for a short time via:
- Activation of neurohumoral systems
- Frank-Starling Mechanism
- Myocardial Hypertrophy
Activation of neurohumoral mechanisms
The body releases NE to increase HR and contractility
The renin-angiotensin system is activated to retain water and salt to increase circulatory volume
Frank-Starling Mechanism
Increased end diastolic filling to stretch cardiac muscle fibers, which cause the fibers to contract more forcefully and increase CO
Eventually, they cannot keep up
Myocardial hypertrophy
Increase in muscle fiber size, resulting in increased thickness of the ventricular wall, but without increase in the size of the lumen
Why do compensatory mechanisms fail?
Due to increase oxygen requirements of the myocardium, but without increased capillary support - resulting in susceptibility to ischemia
How will decompensated muscle look compared to normal?
It will have larger nuclei and not as many fibers
What are some causes of left-sided heart failure? (Etiology)
Ischemic heart disease (IHD) Hypertension Myocarditis Cardiomyopathy Valvular disease
What are some causes of right-sided heart failure?
Left-sided heart failure - subsequent pulmonary congestion leads to an increased arterial pressure
Pulmonary hypertension
Valve disease
Septal defects with left-to-right shunts
What are some manifestations of Congestive heart failure from Left ventricular failure
- Pulmonary edema and congestion, resulting in dyspnea
- Chronic cough
- Orthopnea (can’t breathe laying down)
What are some manifestations of Congestive heart failure from Right and/or Left ventricular failure?
Cerebral hypoxia
What are some manifestations of Congestive heart failure from Right ventricular failure?
Congestion of the liver (nutmeg liver) and spleen
Edema (pitting) of subcutaneous tissues, particularly in the lower extremities
What are the two forms of Congenital heart disease?
Cyanotic
Noncyanotic
What are some causes of Congenital heart disease?
Environmental factors
Chromosomal abnormalities
90% are unknown and likely multifactorial
What are the Noncyanotic forms of congenital heart disease
Atrial Septal Defect - allows shunting between atria
Ventricular Septal Defect - allows shunting between ventricles
Patent ductus arteriosus - connects aorta and pulmonary artery, should close a few days after birth
What are the cyanotic forms of congenital heart disease?
Tetralogy of Fallot
Transposition of the great arteries
What are the 4 anomalies of the Tetralogy of Fallot?
1) Ventricular septal defect
2) Narrowing of right ventricular outflow
3) Overriding of the aorta over ventricular septal defect
4) Right ventricular hypertrophy
Transposition of the great arteries
The right ventricle empties into the aorta
The left ventricle empties into the pulmonary artery
Ischemic Heart Disease
Refers to a group of related disorders that are all characterized by an imbalance between myocardial blood supply and myocardial oxygen demand (ischemia)
Primarily due to atherosclerosis
Leading cause of death in the US
What is the pathogenesis of Ischemic Heart Disease?
Coronary artery atherosclerosis (>75%)
Coronary artery thrombosis
Other factors:
-Increased myocardial oxygen demand (Hypertension)
-Decreased blood volume (hypotension)
-Decreased oxygen (pneumonia)
-Decreased oxygen-carrying capacity (anemia)
What are the different types of Ischemic Heart disease?
Angina Pectoris
Myocardial infarction
Chronic Ischemic Heart Disease with Congestive Heart Failure
Sudden Cardiac death
Angina Pectoris
(Stable Angina)
“Chest Pain” of several minutes usually associated with exercise and emotional stress and relieved by rest
Caused by transient, reversible myocardial ischemia
No myocardial necrosis occurs
Unstable Angina
Increasing frequency of chest pain with minimal/no exertion
Longer lasting than stable angina
Often preceded more serious ischemia or MI
Acute Myocardial Infarction
Necrosis of cardiac muscle caused by ischemia
Severe ischemia lasting longer than 20-40 minutes will cause irreversible myocyte injury and cell death
Myocardial ischemia also contributes to arrhythmias, probably because ischemic regions cause electrical instability - may lead to ventricular fibrilation
Acute Myocardial Infarction Clinical presentation
Chest pain Shortness of breathe Nausea/vomiting Diaphoresis Low-grade fever
Acute Myocardial Infarction PAthology
Coagulation necrosis (few hours) Neutrophil infiltration (few days) Granulation tissue (1 week) Scar formation (weeks-months)
Acute Myocardial Infarction Tests
ECG
Elevated serum proteins from damages cardiac myocytes
How does an MI look in an autopsy?
MI’s less than 12 hours old are not usually grossly apparent at autopsy
At 12-24 hours, infarcted areas appear reddish-blue
Acute Myocardial Infarction Treatment
-Placement of stents to open coronary vessels affected by atherosclerosis
-Coronary artery by-pass grafts (CABG)
-“Clot-busting” drugs such as streptokinase
These may result in reperfusion injury
If a patient survives an acute MI, what is commonly seen?
Scarring of the wall - but this can reduce contractibility, which can also be a problem
Acute Myocardial Infarction Complications
Arrhythmia and sudden death CHF/shock Mural thrombosis/embolism Mitral valve regurgitation Ventricular aneurysm Chronic Ischemic Heart disease
Chronic Ischemic Heart Disease with Congestive Heart Failure
Progressive heart failure due to ischemic myocardial damage
Patient usually has a history of MI
Arrhythmias, CHF and subsequent MI’s lead to many deaths
What is the most common cause of sudden cardiac death?
Ischemic Heart Disease (80-90%)
Sudden Cardiac Death
Sudden onset of ischemic arrhythmia with or without MI
May occur in individuals with or without a history of IHD
What are the Classifications of Cardiomyopathies
Primary - disease primarily or solely confined to a heart muscle
Secondary - myocardium is involved as part of a systemic order
What are the 3 functional/morphological patterns of Cardiomyopathy?
Dilated
Hypertrophic
Restrictive
Dilated Cardiomyopathy
Can be primary or secondary, genetic, or acquired
Hereditary in 20-50% - related to alcoholism
Dilation of all 4 heart chambers
Histology shows variable fibrosis and myocyte hypertrophy
Poor ventricular contractility
Hypertrophic Cardiomyopathy
Primary and Genetic
Autosomal dominant inheritance
Missense point mutation in one of several sarcomeric gene loci
Stiff ventricles prevent adequate filling
Restrictive Cardiomyopathy
Wall of the ventricles becomes stiffer with impaired filling during diastole
Can be idopathic or secondary to systemic conditions that affect the myocardium
What can cause Myocarditis?
Pyogenic bacteria
Viruses
Parasites
Hypersensitivity
Myocarditis caused by Pyogenic Bacteria
Bacteria are usually from abscesses
Myocarditis caused by Viruses
Interstitial mononuclear inflammatory cells with myocyte necrosis
Myocarditis caused by Parasites
In individual myocytes or interstitium with adjacent inflammation
Myocarditis caused by sensitivity
Often to drugs, causes a perivascular inflammatory infiltrate with many eosinophils
