Contractility - ANSWER-is the ability of the heart muscle to shorten
contractility is the potential for myocardial fiber shortening during systole.
It
... [Show More] is determined by the amount of stretch during diastole i.e. preload and by sympathetic stimulation of the ventricles.
Preload - ANSWER-the stretch in the heart to fill up with blood
volume & pressure generated in the ventricle at the end of diastole
Afterload - ANSWER-pressure or force to push the blood out of the heart
is the resistance of ejection of blood from the left ventricle
It is in the load the muscle must move after it starts to contract
Ischemic conditions on cardiac cells - ANSWER-stable angina
Prinzmetal angina
Silent angina
Myocardial Infarction (MI) - ANSWER-local, temporary deprivation of the coronary blood supply
stable angina
prinzmetal angina
silent angina
Nursing Interventions
Signs & Symptoms
Labs
Myocardial Infarction - MI - ANSWER-Signs & Symptoms = manifestations:
sudden severe chest pain; may radiate
nausea, vomiting
diaphoresis, dyspnea
females experience atypical symptoms
Labs:
Troponin
CPK enzymes -isoenzymes
all enzymes maybe delayed by 12 hours
Stable angina - ANSWER-chest pain caused by myocardial ischemia
grandual lumina narrowing & hardening of the arterial walls
affected vessels cannot dilate in response to increased myocardial demand associated with physical exertion or emotional distress, with rest, blood flow is restored, no necrosis occurs
often occurs with activity or emotional stress
Prinzmetal angina - ANSWER-aka variant angina- caused by transient ischemia of the myocardium that occurs unpredictably & while at rest
pain is caused by vasospasm of one or more coronary arteries with or without atherosclerosis
pain at night during REM sleep
may result from decreased vagal activity, hyperactivity of SNS & decreased nitric oxide activity
Silent angina - ANSWER-aka mental stress induced ischemia
ischemia and be totally asymptomatic - such as silent ischemia
they may c/o of fatigue, dyspnea, or feeling of unease
more common in women
Angina Pectoris - ANSWER-commonly known as angina, is the sensation of chest pain, pressure, or squeezing, often due to ischemia of the heart muscle from obstruction or spasm of the coronary arteries
pain is caused by the build up of lactic acid or abnormal stretching of the ischemic myocardium that irritates myocardial nerve fibers.
Systole - ANSWER-ventricles contract, pushing blood out through semilunar valves into the pulmonary artery -right ventricle
the aorta - left ventricle
"contraction"
Diastole - ANSWER-blood flows into the atria, atrioventricular valves are pushed open & blood begins to fill ventricles
"relaxing"
Stroke volume - ANSWER-the amount of blood your heart pumps each time it beats and your heart rate is the number of times your heart beats per minute
Cardio output - ANSWER-is the term that describes the amount of blood your heart pumps each minute
doctors think about cardiac output in terms of the following equation
Cardiac output=StrokeVolume x Heart Rate
Renin-Angiotensin-Aldosterone System
RAAS - ANSWER-Renal juxtaglomerular cells sense decrease in BP & release renin-->renin activates angiotensinogen to angiotensin I-->angiotensin I is converted to angiotensin II via angiotensin - converting enzyme ACE in the lung capillaries --> angiotensin II promotes vasoconstriction & stimulates aldosterone secretion from adrenal cortex resulting in renal sodium & H2O retention, potassium excretion, & an increase in BP --> aldosterone causes increased reabsorption of sodium & H2O retention
Atherosclerosis - cause - ANSWER-most common MI
causes- smoking, hypertension, diabetes, increased levels of low-density lipoprotein -LDL-, decreased levels of high-density lipoprotein - HDL, & autoimmunity
Atherosclerosis - Patho process - ANSWER-begins with injury to the endothelial cells that line artery walls
pathologically, the lesions progress from endothelial injury & dysfunction to fatty streak to fibrotic plaque to complicated lesion
Lipoprotein involved in the process - LDL - ANSWER-increased levels of low-density lipoprotein
Chambers of the heart - ANSWER-Right-Tri-Right, Pul-Pul-Pul, Lung-Pul-Left, BLAA
Right- Right Atrium
Tri- Tricuspid valve
Right- Right ventricle
Pul- Pulmonary Semilunar valve
Pul- Pulmonary Trunk
Pul- Pulmonary Arteries
Lung- Lung capillaries
Pul- Pulmonary veins
Left- Left Atrium
B- Bicuspid
L-Left ventricle
A- Aortic Semilunar valve
A- Aorta
Chambers of the Heart - simplified - ANSWER-Right atrium
Left atrium
Right ventricle
Left ventricle
i.e. blockage in pulmonary artery would result in blockage of the right ventricle
The Valves of the Heart - ANSWER-Atrioventricular valves:
Tricuspid valve
Mitral valve
Semilunar valves:
Pulmonic semilunar valve
Aortic semilunar valve
One way blood flow through the heart is completed by 4 heart valves. - ANSWER-
Arterioventricular valves - ANSWER-during ventricular relaxation, the two valves open and blood flows from the atria to the relaxed ventricles. As the ventricles contract, increasing ventricular pressure causes these valves to close and prevent back flow into the atria.
1. Tricuspid valve - right AV valve
2. mitral valve - left AV valve
Semilunar valves - ANSWER-open when intraventricular pressure exceeds aortic and pulmonary pressure, and blood flows out of the ventricles and into the pulmonary and systemic circulations. After ventricular contraction and ejection, intraventricular pressure falls and the semilunar valves close, preventing backf low into the right and left ventricles.
1. pulmonic valve
2. aortic valve
Blood Pressure
Normal & Abnormal Assessment - ANSWER-Normal <120 Systolic (mmHg) & <80 Diastolic (mmHg)
Prehypertension 120-139 Systolic (mmHg) or 80-89 Diastolic (mmHg)
Stage 1
Hypertension 140-159 Systolic (mmHg) or 90-99 Diastolic (mmHg)
Stage 2
Hypertension >160 Systolic (mmHg) or > 100 Diastolic (mmHg)
Primary Hypertension - ANSWER-essential or idiopathic HTN
genetic & environmental factors
affects 92% to 95% of individuals with hypertension (HTN)
risk factors:
high sodium intake
natriuretic peptide abnormalities
obesity
insulin resistance
Secondary Hypertension - ANSWER-caused by a systemic disease process that raises peripheral vascular resistance or cardiac output
renal artery stenosis, renal parenchymal disease, pheochromocytosis, drugs
Risk for Coronary Artery Disease - ANSWER-any vascular disorder that narrows or occludes the coronary arteries leading to myocardial ischemia
atherosclerosis is the most common cause
Labs: LDL's & HDL's
Risk factors: Increased age, family history, male gender, or menopause
What is an Aneurysm? - ANSWER-a localized, blood-filled balloon-like bulge in the wall of a blood vessel
Aneurysms can occur in a any blood vessel
Thrombus - ANSWER-blood clot that remains attached to the vessel wall
2 components to a thrombus:
1. aggregated platelets that form a platelet plug
2. mesh of cross-linked fibrin protein
Risk factors:
trauma or inflammation, obstruction of flow, pooling-stasis
Thrombus - Patho - ANSWER-A thrombus occurs when the hemostatic process, which normally occurs in response to injury, becomes activated in an uninjured or slightly injured vessel. A thrombus in a large blood vessel will decrease blood flow through that vessel - termed a mural thrombus. In a small blood vessel, blood flow may be completely cut off. Termed an occlusive thrombus, resulting in death of tissue supplied by vessel. If a thrombus dislodges & becomes free-floating , it is considered an embolus.
Embolus - ANSWER-lodging of an embolus, which may be a blood clot, fat globule, gas bubble or foreign material, in the blood stream. This can cause a blockage in the blood vessel. Such a blockage - a vascular occlusion - may affect a part of the body distant from where the embolus originated. This is in contrast to a thrombus, which causes a blockage at the site of origin.
Thromboembolism - ANSWER-obstruction of a blood vessel by a blood clot that has been dislodged from another site in the circulation
Venous Thrombus - ANSWER-blood clot that forms in the vein
more common because flow & pressure is lower than arterial
Deep Vein Thrombosis - ANSWER-obstruction of venous flow leading to increased venous pressure
blood clots in veins which are lying deep in the skin i.e. leg
factors: Triad Virchow
1. Venous Stasis
2. Venous endothelial damage
3. Hypercoagulable states - malignancy, pregnancy, use of oral contraceptives, inherited, etc.
other: cancer, orthopedic surgery/trauma, heart failure, immobility
Venous Insufficiency - ANSWER--varicose veins
A vein in which blood has pooled
Distended, tortuous & palpable veins
Caused by trauma or gradual venous distention
eventually, the psi in the vein damages venous valves, making them unable to maintain normal venous psi
CVI
Chronic Venous Insufficiency (CVI) - ANSWER-Inadequate venous return over a long period due to varicose veins or valvular incompetence
Venous Stasis Ulcers
S/S = edema of LE - sometimes knees- & hyperpigmentation of skin ob feet & ankles
circulation can become so sluggish that metabolic demands of the cells to obtain O2 & nutrients are barely met. Therefore, ulceration is caused by pressure that reduced oxygen supply to the cells & then causes cell death & necrosis.
Circulatory System - ANSWER-Functions to deliver O2, nutrients, & other substances to all of the body's cells and to remove waste products of cellular metabolism
The delivery & removal is completed by blood vessels & heart.
Output of one = input of another
Heart pumps blood to 2 circulatory options
1. Lungs
2. Rest of the body
Arteries carry blood from the heart to the body where they branch to smaller vessels-capillaries
capillaries - veins - body - heart
Left sided HF - simplified - ANSWER-Pulmonary circulation
Pumps blood through the lungs
Heart Failure Patho
Signs & Symptoms
LEFT SIDED
Systolic HF - ANSWER-systolic heart failure - left heart failure
inability of the heart to generate adequate cardiac output to perfuse tissues
ventricular remodeling
causes include:
myocardial infarction, myocarditis, cardiomyopathy
Heart Failure Patho
Signs & Symptoms
Left sided
Diastole HF - ANSWER-diastolic HF- Left heart failure
pulmonary congestion despite normal stroke volume & cardiac output
causes include: myocardial hypertrophy & ischemia, diabetes, valvular & pericardial disease
Left Heart Failure Patho - ANSW [Show Less]