Describe how this compensatory mechanism increases cardiac output as a result of heart failure, and indicate the long term effects.
Sympathetic Nervous System�adrenergic receptors
Action: Increased heart rate (beta-adrenergic) and blood pressure from vasoconstriction (alpha-adrenergic). There is also increased venous return to the heart, which stretches the myocardial fibers. This increased stretch is a preload that makes a more forceful contraction, increasing stroke volume and CO. Long-term effects: Increased oxygen demand; increased afterload, which is the resistance against which the heart must pump; too much myocardial stretch (preload).
Describe how this compensatory mechanism increases cardiac output as a result of heart failure, and indicate the long term effects.
Cardiac hypertrophy
Action: The walls of the heart become thick, increasing muscle mass and increasing the force of contraction. Long-term effect: The heart cannot meet the increased oxygen demand that hypertrophied condition requires.
Describe how this compensatory mechanism increases cardiac output as a result of heart failure, and indicate the long term effects.
Hormonal response
Action: Activates the renin-angiotensin system, which raises the blood pressure by increasing fluid retention and vasoconstriction. Long-term effect: This eventually increases the stretch (preload) and theresistance (afterload). Ventricular remodeling may develop.
Left ventricle is unable to contract
forcefully. LV is unable to eject blood
adequately into the circulation.
Systolic dysfunction (systolic ventricular dysfunction)
Effects of Systolic Ventricular Dysfunction
Cardiac output decreases. Symptoms of inadequate tissue perfusion, pulmonary and systemic congestion occur.
Left ventricle is unable to relax
during diastole; this prevents the
ventricle from filling.
Diastolic dysfunction (diastolic ventricular dysfunction)
Effects of Diastolic Ventricular Dysfunction
Diminished tissue perfusion and decreased cardiac output. Symptoms similar to those of systolic dysfunction.
Differentiate between the terms arteriosclerosis and atherosclerosis
Arteriosclerosis is a thickening or hardening of the arterial wall resulting in a loss of elasticity.
Atherosclerosis is a form of arteriosclerosis that involves the formation of plaque within the arterial wall, which leads to eventual interference with blood flow through the artery.
List in order the development of atherosclerosis
Intimal layer of artery is injuredFatty streak is deposited on intimal layerFibrous plaque developsCalcification, thrombosis, ulceration of fibrous lesions occur
Describe the characteristics of plaque in the development of atherosclerosis
Plaque is white and fibrous, and partially or completely blocks the flow of blood in an artery
List the causes of injury to the inner layer of the arterial wall that contributes to the development of atherosclerosis
Mechanical Injury: hypertensionChemical Injuries: toxins from renal failure, carbon monoxide from smokingNatural Causes: agingDiseases: diabetes, hyperlipidemiaOthers: stress (type A personality is uptight, type D personality is depressed), obesity, and sedentary lifestyle
Describe the rate of progression and factors that influence the development of atherosclerosis
Rate of progression depends on factors that cause the injury and the number of risk factors that a patient has.For example, if a patient is older, eats a high fat diet, and has diabetes, the rate of progression is high.
Describe the characteristics of a fatty streak in the development of atherosclerosis
A fatty streak is a fatty deposit on the inner lining of the arteries but not enough to affect the integrity of the arterial wall
What are the waist measurements that determine risk for CVD?
Women with waists greater than 35inMen with waists greater than 40in
When a mature atherosclerotic plaque develops, it is not uniform and has a lipid liquid center filled with procoagulant factors. A connective tissue fibrous cap covers the top of the fluid lipid center.
What happens when this cap abruptly ruptures?
The abrupt rupture allows procoagulant lipids to flood into the vessel lumen and rapidly form a coronary thrombosis. As the enlarging clot blocks blood flow through the coronary artery, a "heart attack" will occur unless there is adequate collateral circulation from other coronary vesselsSymptoms associated with this cap rupture include chest pain not relieved by rest or Nitro. This is considered an Acute Coronary Syndrom- unstable angina
Type of atherosclerotic plaque that is prone to rupture has a weak fibrous cap and a large amount of liquid cholesterol within the core
Vulnerable plaqueAs deep fissures in the cap expose the procoagulant factors to the blood plasma, an unstoppable cycle is put into motion. As the liquid inner core travels through the cardiovascular system, it collects RBCs and other debris along the way forming a clot that can occlude the coronary artery(microembolism occulsion)Vulnerable plaques are usually not obstructive like calcified plaques are
Type of atherosclerotic plaque that can't rupture but can occlude the coronary arteries
Calcified PlaqueAlthough stable it can occludeThe part of the artery that is calcified can no longer constrict or dilateCalcified plaque is related to the aging process where vulnerable plaque is related to lifestyle
Will lowering cholesterol levels change the dimensions of the fibrous or calcified portions of the plaque?
No but, it can decrease the plaque size by decreasing the amount of liquid cholesterol within the plaque core.Lower cholesterol levels also reduce vascular inflammation and make vulnerable plaque less likely to rupture
Term used to describe the array of clinical presentations of coronary artery disease (CAD) that range from unstable angina to acute MI
Acute Coronary Syndrome (ACS)
Stable manifestation of CAD is referred to as stable anginaAcute manifestations of CAD are described as an acute coronary syndrome and refers to unstable angina and acute MI
Chest pain caused by myocardial ischemia and is a symptom of coronary artery disease
Angina
It is a symptom not a separate disease
Angina is caused by a blockage or spasm of a coronary artery, leading to diminished myocardial blood supply. The lack of oxygen causes myocardial ischemia, which the patient describes as?
Chest discomfort, pressure or painAngina may occur anywhere in the chest, neck, arms, or back. Most commonly described location is pain or pressure behind the sternum that radiates to the left arm but can also radiate down both arms and to the back, shoulder, jaw, or neckTeach that angina does not always present in the dramatic scenarios seen on TV
Many women experience a variety of different symptoms before and during an acute MI. It is important that all patients are made aware of angina symptom equivalents, such as?
Unexpected shortness of breathBreaking out in a cold sweatSudden fatigue, nausea, or lightheadednessMore women die every year of cardiovascular disease than men
What are the effects of the Parasympathetic Nervous System on: Automaticity, Contractility, Conduction velocity, and Rate?
Parasympathetic Nervous System Decreases all functions
What are the effects of the Sympathetic Nervous System on: Automaticity, Contractility, Conduction velocity, and Rate?
Sympathetic Nervous System Increases all functions
Type of angina that is predictable and caused by similar precipitating factors each time; typically, it is exercise induced
Stable Angina
Stable angina is the result of?
Fixed lesions (blockages) of more than75% of the coronary artery lumenIschemia and chest pain occur when myocardial demand from exertion exceeds the blood oxygen supplyPain control should be achieved within 5 minutes by rest and by taking sublingual nitro
Defined as a change in previously established stable pattern of angina, and is part of the continuum of acute coronary syndrome
Unstable AnginaMore intense than stable angina, may awaken the person from sleep, or may necessitate more than nitrates for pain reliefA change in the level or frequency of symptoms requires immediate evaluationSevere angina that persists for more than 5 minutes, is worsening in intensity, and is not relieved by one nitro tablet is a medical emergency
Unstable angina is an indication of?
Atherosclerotic plaque instabilityIt can signal atherosclerotic plaque rupture and thrombus formation that can lead to MI
Severe angina persisting longer than 5 minutes or worsening symptoms without relief from rest or sublingual nitro indicates?
Preinfarction symptoms (Unstable Angina)
Pathophysiology of Acute Coronary Syndrome
AtherosclerosisACS
Chronic inflammation of arterial wall Plaque formation Atherosclerotic plaque ruptures And/Or