Chapter 12 Summary
- Heart function may be impaired by conduction system abnormalities, interference with
the blood supply to the myocardium, or structural abnormalities. Arterial and venous
disorders usually affect cardiac function as well. Multiple long term factors usually
predispose to heart dysfunction. Treatment of cardiovascular disorders frequently
involves dietary changes, exercise programs, and cessation of cigarette smoking, as well
as drug therapy and possibly surgery.
- Arteriosclerosis refers to degeneration of small arteries with loss of elasticity;
development of thick, hard walls and narrow lumens causing ischemia; and possibly local
necrosis.
- In atherosclerosis, cholesterol plaques and thrombi obstruct larger arteries such as the
aorta and the coronary and carotid arteries. Obstructions may be partial or complete, and
emboli are common. Factors such as genetic conditions, high cholesterol diet, elevated
serum LDL levels, and elevated blood pressure predispose patients to the development of
atheromas.
- Angina pectoris attacks are precipitated when the demand for oxygen by the myocardium
exceeds the supply. Chest pain is relieved by intake of the vasodilator nitroglycerin and
decreasing demands on the heart.
- MI results from total obstruction in a coronary artery, resulting in tissue necrosis and loss
of function. Continuing chest pain, hypotension, and typical changes in the ECG are
diagnostic. Arrhythmias are a common cause of death shortly after infarction occurs.
- Cardiac arrhythmias may result from MI or systemic abnormalities such as electrolyte
imbalance, infections, or drug toxicity. Arrhythmias include abnormally slow or rapid
heart rates, intermittent additional heart contractions (extrasystoles) or missed
contractions (heart blocks).
- Depending on the cause, CHF may develop first in either the right or the left side of the
heart, causing systemic backup and congestion or pulmonary congestion, respectively. In
either case, cardiac output to the body is reduced, causing general fatigue and weakness,
and stimulating the renin-angiotensin mechanism.
- Congenital heart defects consist of a variety of single or multiple developmental
abnormalities in the heart. These structural abnormalities may involve the heart valves,
such as mitral stenosis; the septae, such as ventricular septal defect, the proximal great
vessels; or a combination of structural defects. The primary outcome is decreased oxygen
to all cells in the body. Cyanotic defects such as the tetralogy of fallot refer to congenital
defects where blood leaving the left ventricle consists of mixed oxygenated and
deoxygenated blood, thereby delivering only small amounts of oxygen to all parts of the
body.
- Rheumatic fever is a systemic inflammatory condition caused by an abnormal immune
response to certain strains of hemolytic streptococcus. Inflammation causes scar tissue on
heart valves and in the myocardium leading to rheumatic heart disease.
- Heart function may be impaired by conduction system abnormalities, interference with
the blood supply to the myocardium, or structural abnormalities. Arterial and venous
disorders usually affect cardiac function as well. Multiple long term factors usually
predispose to heart dysfunction. Treatment of cardiovascular disorders frequently
involves dietary changes, exercise programs, and cessation of cigarette smoking, as well
as drug therapy and possibly surgery.
- Arteriosclerosis refers to degeneration of small arteries with loss of elasticity;
development of thick, hard walls and narrow lumens causing ischemia; and possibly local
necrosis.
- In atherosclerosis, cholesterol plaques and thrombi obstruct larger arteries such as the
aorta and the coronary and carotid arteries. Obstructions may be partial or complete, and
emboli are common. Factors such as genetic conditions, high cholesterol diet, elevated
serum LDL levels, and elevated blood pressure predispose patients to the development of
atheromas.
- Angina pectoris attacks are precipitated when the demand for oxygen by the myocardium
exceeds the supply. Chest pain is relieved by intake of the vasodilator nitroglycerin and
decreasing demands on the heart.
- MI results from total obstruction in a coronary artery, resulting in tissue necrosis and loss
of function. Continuing chest pain, hypotension, and typical changes in the ECG are
diagnostic. Arrhythmias are a common cause of death shortly after infarction occurs.
- Cardiac arrhythmias may result from MI or systemic abnormalities such as electrolyte
imbalance, infections, or drug toxicity. Arrhythmias include abnormally slow or rapid
heart rates, intermittent additional heart contractions (extrasystoles) or missed
contractions (heart blocks).
- Depending on the cause, CHF may develop first in either the right or the left side of the
heart, causing systemic backup and congestion or pulmonary congestion, respectively. In
either case, cardiac output to the body is reduced, causing general fatigue and weakness,
and stimulating the renin-angiotensin mechanism.
- Congenital heart defects consist of a variety of single or multiple developmental
abnormalities in the heart. These structural abnormalities may involve the heart valves,
such as mitral stenosis; the septae, such as ventricular septal defect, the proximal great
vessels; or a combination of structural defects. The primary outcome is decreased oxygen
to all cells in the body. Cyanotic defects such as the tetralogy of fallot refer to congenital
defects where blood leaving the left ventricle consists of mixed oxygenated and
deoxygenated blood, thereby delivering only small amounts of oxygen to all parts of the
body.
- Rheumatic fever is a systemic inflammatory condition caused by an abnormal immune
response to certain strains of hemolytic streptococcus. Inflammation causes scar tissue on
heart valves and in the myocardium leading to rheumatic heart disease.
