Chapter 17

from lungs to back to the heart:

- After the blood is oxygenated in the alveoli of the lungs, it returns to the left atrium via the pulmonary veins. -The blood in the left atrium is then ejected through the mitral valve (also called the bicuspid valve) and into the left ventricle upon contraction of the atria. - On the next ventricular contraction, the blood is ejected through the aortic semilunar valve and into the aorta. -The blood is then distributed throughout the body to cells and organs.

Pathophysiology of Angina

- Angina pectoris is a symptom of inadequate oxygen supply to the heart muscle or myocardium. Often caused by partial blockage of the coronary arteries. -The lack of oxygen causes the discomfort, sometimes described as "crushing" or "squeezing," or as "tightness" by the patient. -Generally occurs during periods of stress, either physical or emotional. Once the stress relieved or removed or the patient rests, the pain will usually go away. -The pain is usually felt under the sternum and may radiate to the jaw, down either arm, to the back or to the epigastrium. -Pain usually lasts between 2-15 minutes. -If the patient has had a history of angina they may have nitroglycerin prescribed to them for this condition. -Prompt relief of the symptoms after rest and administration of nitro is typical of angina.

Conductive Cells/Conduction System (continued)

- Conductive cells are grouped in three areas of the heart, known as Pacemaker Sites. This is where electrical impulses are generated automatically, independent of the autonomic nervous system of the body. - One pacemaker site is the Sinoatrial Node (SA Node). It is located in the upper portion of the right atrium. The SA node, known as the primary pacemaker of the heart, generates the impulse that triggers the rest of the heart to contract. -A secondary pacemaker site is located on the crux. This pacemaker site is known as the Atrioventricular node (AV Node), only creates an impulse if the sinoatrial (SA) node fails. - The final pacemaker, known as the Purkinjie Fibers, site is widely distributed in the conduction system of the ventricles. These fibers deliver the impulse to the working cells of the heart. If both higher pacemaker sites fail, the Purkinje network can also initiate an impulse to maintain some ventricular contraction.

What are the components of the blood?

- The liquid portion of the blood, the serum, serves as the transport medium for the formed elements. -the formed elements include: the red blood cells which, among other functions, carry oxygen to the tissues of the body. There are also white blood cells that serve to protect the body and eliminate infections from viruses and bacteria. Platelets are cellular elements whose job is to help in the clotting process or stop bleeding.

Cause of Congestive Heart Failure

- The pressure in the aorta is very high; therefore, the left ventricle must generate a significant amount of force to eject the blood against this pressure. If the pressure in the aorta is excessively high, as seen in severe hypertensive patients (those with very high blood pressure), or if the blood pressure is simply higher than normal over a long period of time, the left ventricle will begin to weaken and fail. - Also, if the left ventricle muscle is damaged due to a blockage of a coronary artery, the ventricle will weaken and will not be able to pump an adequate amount of blood out of the left ventricle. This may least to congestive heart failure, also known as left ventricular failure.

The pathway the blood takes through the heart to the pulmonary artery and lungs:

- The right atrium receives deoxygenated blood from the inferior and superior vena cavae, the largest veins within the body. -upon contraction, the blood in the right atrium travels through the tricuspid valve and into the right ventricle. - from the right ventricle, with the next contraction, the deoxygenated blood is ejected through the pulmonic semilunar valve and into the pulmonary arteries. -The pressure in the pulmonary vessels is very low; thus the right ventricle does not have to generate a great deal of force to eject the blood.

Autonomic nervous system and role in the hearts activity.

- The sympathetic branch of the autonomic nervous system innervates all three pacemaker sites and the working cells of the heart. - When the body needs increased blood flow, the sympathetic nervous system is stimulated and causes the heart to beat faster and with greater contractile force, which increases the ejection of blood. - The parasympathetic branch of the autonomic nervous system innervates the sinoatrial and atrioventricular nodes. - When the parasympathetic nervous system is stimulated, it slows the heart rate and eases the force of contraction. This diminishes cardiac output in situations where strong output is not needed, for example while the body is sleeping or at rest.

Working Cells

- also called Contractile Cells - their primary purpose is to contract in response to the electrical impulses provided by the conduction system. -These working cells have characteristics of both smooth (involuntary muscle) and skeletal (voluntary muscle). -Like Skeletal muscle, they contract strongly when stimulated to help eject blood from the heart. -Like smooth muscle, they contract completely, to a very small size, because the heart has to collapse upon itself in order to push blood out of the chambers.

The Circulatory System

-Also known as the cardiovascular system, has three major components: 1. The Heart 2. The blood vessels 3. The blood -Each of these components may play a significant role in patients experiencing a cardiac related emergency.

The Heart

-The heart consists of four chambers: the atria (the two top chambers) and the ventricles (the two bottom chambers). -The heart has only one purpose: pumping blood within the body. - If that single purpose is interrupted, even momentarily, cardiac arrest ensues and the chance of survival is slim.

Conduction Pathway

-The heart's electrical impulses travel through the heart from the pacemaker sites via a conduction pathway that is composed of cells that neither initiate an impulse not contract. -The cells of the conduction pathway rapidly conduct each impulse to the rest of the heart muscle. -They do this in a unified fashion so that, rather that the whole heart contacting at once, there is a sequential contraction of the chambers.

Unstable Angina

-has a variety of definitions -usually indicates angina discomfort that is prolonged and worsening, or that occurs without exertion and when the patient is at rest.

Angina Pectoris

-literally means "pain in the chest" is a symptom commonly associated with coronary artery disease. -Classic angina typically occurs upon an increased workload placed on the heart. This may be from an increase in the heart rate or contractile function.

Diabetes

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Gran Mal Seizure

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How do you give Nitro? if the patient has it

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L.A. Prehospital Stroke Screen

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Seizures

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Status Epilepticus

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TIA

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What are the signs and symptoms of a CHF heart attack?

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What are the signs and symptoms of a stroke victim?

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What are the signs and symptoms of heart failure?

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What forms does oral glucose come in?

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What is Insulin?

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What is a Sient MI?

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What is a neurological deficit?

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What is the Cincinnati Pre-Hospital Stroke Scale?

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When, why, and how do we give aspirin?

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Who is most likely to suffer from a Silent MI?

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Atherosclerosis

Arteriosclerosis is a condition that causes the smallest of the arterial structures to become still and less elastic. A form of arteriosclerosis is atherosclerosis Atherosclerosis is a systemic arterial disease. It is underlying pathogenic process in the majority of patients that have coronary artery disease that causes myocardial infarctions as well as the arterial changes that result in stroke. Atherosclerosis is an inflammatory disease that starts with the intimal lining of the blood vessels, where endothelial cells become damaged.

Hearts Sole Purpose

Pumping blood. The conduction cells and working cells operate together in unison so that the heart can pump blood.

Acute Coronary Syndrome

Results from a variety of conditions that can affect the heart in which the coronary arteries are narrowed or occluded by fat deposits (plaque), clots, or spasm. Two conditions that are part of any acute coronary syndrome are: - unstable angina - myocardial infarction (heart attack)

Elecrocardiogram

The electrocardiogram (ECG or EKG) is a graphic representation of the heart's electrical activity as detected from the chest wall surface. P Wave- This is the first waveform of the ECG and represents the depolarization (contraction) of the atria. QRS Complex- This is the second waveform and represents the depolarization of the ventricles and the main contraction of the heart. T Wave- This is the third waveform and represents the repolarization (relaxation) of the ventricles. The atria also have a repolarization wave but it is typically hidden within the QRS complex

The Conduction System

The heart is more than just a muscle. It contains specialized conductive tissue, which generates electrical impulses that are conducted rapidly to other cells of the heart (a property known as conductivity). The heart also contains specialized contractile tissue that allows the heart muscle to contract when stimulated by the electrical impulses from the conduction system.

What is the main function of the heart?

To pump blood within the body - If that single purpose is interrupted, even for a moment, cardiac arrest ensues, and the chance for survival is slim

Heart Failure

When the heart no longer has the ability to adequately eject blood out of the ventricle, it is considered to be failing. The heart failure may be a result of a heart attack that affected a large portion of muscle because, when the heart muscle dies, it no longer contributes to the pumping function of the heart.

Emergency medical care for someone with Angina

administer supplemental o2 if the patient is dypneic hypoxic, and obvious signs of heart failure, has an spo2 reading of <94% or spo2 is unknown. administer o2 via nasal cannula at 2 to 4 lpm if patients respirations become inadequate begin ppv. If the patient has prescribed nitroglycerin and his systolic blood pressure is greater than 90 mmHg, place him in a sitting ot lying position and administer the nito tablets or spray. Three sprays or tablets can be administered over a 10 minute period. if the patient is suspected of suffering from a coronary artery occlusion, administer 160-325 mg of aspirin if you local protocol allows it.

Ischemic Stroke

when there is a blockage in a cerebral artery causing the brain or part of the brain to not get enough blood.