Chapter 11 Part II: Cardiovascular System Flashcards
Heart: Arrhythmias / dysrhythmias
• Heart block (atrioventricular block)
• Flutter
• Fibrillation
Examples of cardiac arrhythmias: Bradycardia (slow HR) and heart block (atrioventricular / AV block)
Improper conduction of impulses from SA node through AV node to AV bundle?
- SA node damage with weak impulses?? Can result in bradycardia with “skipped” heartbeats. If no impulse reaches AV node, then we have a complete “AV block” that can also result in Rt and Lt bundle branch block (RBBB, LBBB).
- Implantation of cardiac pacemaker.
Examples of cardiac arrhythmias: Flutter
Rapid but regular contraction, usually in the atria.
- May reach 300 BPM
- Tx includes meds, cardioversion
Examples of cardiac arrhythmias: Fibrillation
Very rapid, random, inefficient and irregular contractions of the heart (350 BPM or more).
- Atrial fibrillation (AF, “A fib”): most common arrhythmia, 5-10% in 70-80 YO or >15% in 80 YO’s.
- Pt experiences palpitation (uncomfortable sensations in the chest) that can be paroxysmal or permanent.
Examples of cardiac arrhythmias: Ventricular fibrillation
- Electrical impulses move randomly throughout the ventricles.
- Can be life-threatening and result in sudden cardiac death or cardiac arrest.
- Treat with meds (digoxin, beta-blockers and calcium channel blockers) or if urgent, defibrillation.
Examples of cardiac arrhythmias: Ventricular fibrillation
Implantable cardioverter-defibrillator (ICD)
Implanted inside the chest to sense arrhythmias and terminate them with a shock.
Ventricular Tachycardia
Ventricular rate may be as high as 250 beats per minute. The rhythm is regular, but the atria are not contributing to ventricular filling and blood output is poor.
Ventricular Fibrillation
Notice the abnormal, irregular waves. Ventricles in fibrillation cannot pump blood effectively. Circulation stops and sudden cardiac death follows if fibrillation is not reversed.
Congenital heart disease:
- Coarctation of the aorta (CoA)
- Patent ductus arteriosus (PDA)
- Septal defects (ASD and VSD)
- Tetralogy of Fallot
Contraction of the aorta (CoA)
Localized narrowing of the aorta reduces the supply of blood to the lower part of the body.
Patent ductus arteriosus (PDA)
The ductus arteriosus fails to close after birth, and blood from the aorta flows through it into the pulmonary artery.
Ductus Arteriosus ————>
Ligamentum Arteriosum
Congenital
Born with it.
Septal defect
• Small holes in the wall b/w the atria (atrial septal defect, ASD) or the ventricles (ventricular septal defect, VSD)
- If the holes do not close spontaneously, will require an open heart surgery with a heart-lung machine.
Ventricular septal defect
A hole in the ventricular septum causes blood to flow from the left ventricle to the right and into the lungs via the pulmonary artery.
Congestive heart disease (CHF)
The heart is unable to pump the required amount of blood.
• In the U.S., primarily the result of high blood pressure and coronary artery disease.
• Symptoms include pulmonary edema (fluid accumulation in the lungs), swelling/edema in the legs, feet and ankles.
• Tx includes: meds including diuretics to promote fluid loss, lifestyle modification (less Na intake, diet control) or surgery if others fail.
Pulmonary circulation
- Blood picks up oxygen; blood loses carbon dioxide.
- Blood flow from the heart to lung capillaries and back to the heart.
Systemic circulation
- Blood loses oxygen to cells; blood picks up carbon dioxide.
- Blood flow from the heart to tissue capillaries and back to the heart.
Coronary artery disease (CAD): Atherosclerosis
Plague formation inside of the coronary vessels.
- Thrombotic occlusion (occlusive/mural): obstruction of the vessels through blood clots.
- Ischemia: Blood being held back from reaching the target tissue.
(Zone of ischemia, down to the Zone of injury, down to the Zone of infarction)
- Necrosis: Heart muscle does not receive enough oxygenation and so it starts to die.
- Infarction: once the heart muscle is dead.
Coronary artery disease (CAD): Acute Coronary Syndromes (ACS)
Chest pain because you are exerting.
- Unstable angina: chest pain is very unpredictable.
- Myocardial infarction (MI): permanent death of the myocardium.
Coronary artery disease (CAD): Drug therapies for CAD
- Nitrates (nitroglycerin): take when you experience chest pain, very quick acting and very effective vasodilator. (Take orally under the tongue).
- Aspirin: after you have a heart attack, they ask you to take it for the rest of your life. It can help prevent the blood clot formation.
- Beta-blockers
- ACE inhibitors
- Calcium channel blockers
- Statins: the anti-cholesterol medication that they often prescribe to patients who have already had a heart attack with high cholesterol levels.
Coronary artery disease (CAD): Surgical therapies for CAD
- Coronary artery bypass grafting (CABG): if the stent is not successful they create a bypass to get blood from one point to another.
- Percutaneous coronary intervention (PCI): insert catheter into the aorta in the heart and in a vessel that is obstructed. Then they inflate the balloon to open up the obstructed vessel and leave a metal stent inside the obstructed coronary vessel to keep the vessel open.
Other pathologic conditions:
• Endocarditis (vegetations): inflammation of the endocardium. Inflamed with abnormal vegetations.
• Hypertensive heart disease
• Mitral valve prolapse (MVP)
• Murmur
• Pericarditis
• Rheumatic heart disease
Hypertensive heart disease
HTN or high BP due to increased resistance in the arteries (narrowing, atherosclerosis, etc) resulting in left ventricular hypertrophy (LVH)
