Chapter 12- The Heart Flashcards
What is the number one cause of worldwide mortality?
Cardiovascular disease
What is myocardium?
Heart muscle
What are the phases of heart pumping?
Contraction (systole) and relaxation (diastole)
What are the contractile components of the heart?
Sarcomeres
What is ANP secreted in response to?
Increased blood volume in the heart
What are the names for the components of AV and semilunar valves?
AV- leaflets
Semilunar- cusps
What is the pacemaker of the heart?
The SA node
Where do the conducting components of the heart lie?
SA node- junction if the right atrial appendage and SVC
AV node- right atrium (along septum)
Bundle of His- through the septum
Purkinje network- divisions into the right and left ventricles
What is the division of the Purkinje network called?
Arborization
When does blood flow to the myocardium occur?
Diastole
What are the supply vessels of the heart for each area?
Anterior
- Right coronary, right marginal
- Left coronary, left anterior descending, left marginal
Left posterior- left circumflex
Right posterior- posterior left ventricular branch
What are the effects of aging on the heart?
Sigmoid septum
Valve sclerosis and degenerative changes
Decreased myocytes and increased fibrosis
Aortic stiffness
Atherosclerosis
What are the causes of cardiac pathophysiology?
Pump failure
Flow obstruction
Regurgitant flow
Shunted flow
Abnormal conduction
Rupture of heart or major vessels
What is congestive heart failure?
End stage heart disease
Heart is unable to maintain output
What is forward failure vs backward failure?
Forward- trouble getting blood out (reduced CO and tissue perfusion)
Backward- blood pooling
What is the most common cause of CHF?
Systolic dysfunction
When is diastolic dysfunction seen as he cause of CHF?
Women over 65
What are two compensatory mechanisms for CHF?
- Frank-Starling mechanism (heart dilated with increased filling and enhances contraction)
- Myocardial hypertrophy
What are the three types of cardiac hypertrophy?
- Pressure overload- hypertension or stenosis (concentric increased in wall thickness)
- Volume overload- valvular insufficiency or ventricular dilation (no thickened wall, just bigger)
- Physiologic- exercise, increased mitochondria and angiogenesis
What are the characteristics of left sided heart failure?
Systolic failure
Left ventricle is hypertrophied and dilated
Secondary left atrium dilation (A-fib)
How does left sided heart failure manifest?
Pulmonary congestion and edema
Left atrial dilation
Decreased atrial perfusion (salt and water retention)
Hypoxic encephalopathy
What is the most common cause of right sided heart failure?
Left sided heart failure
What is right sided heart failure infrequently isolated as?
Cor pulmonale (alterations in structure and function due to pulmonary disorders)
What are the characteristics of right side heart failure?
Edema
Hepatomegaly with centrilobar congestion (nutmeg liver)
Congestive splenomegaly
Renal congestion
What is the pharmacological treatment for CHF?
Diuretics (relieve fluid overload)
Beta blockers (lower adrenergic tone)
When does most congenital heart disease occur?
Week 3-8
What are common congenital heart diseases?
Single gene mutations
DiGeorge
Down
Environmental factors
Lesions (obstructions and shunts
Left to right shunts result in what?
Right sided volume and pressure overload
Pulmonary hypertension
What is Eisenmenger syndrome?
Pulmonary pressure increases so much a left shunt occurs (overcorrects the left to right shunt)
What are the types of left to right shunts and their characteristics?
- Atrial septal defects- adults, increased distendability of the right ventricle, murmur
- Ventricular septal defects- membranous septum near aortic valve, right ventricular hypertrophy and pulmonary hypertension
- Patent ductus arteriosus- distal to left subclavian artery, ligamentum arteriosum failed to close (aorta and pulmonary artery)
What is the most common CHD overall?
Ventricular septal defects
What are the types of atrial septal defects?
- Primum- adjacent to mitral and tricuspid valves
- Secondum (90%)- deficient septum secondum formation near atrial septum
Sinus venosus- near SVC entrance
What is patent foramen ovale?
Defective sealing of fossa ovalis flap
What is associated with right to left shunts?
Tetralogy of Fallot and transposition of great arteries
What is tetralogy of Fallot?
VSD
Pulmonary stenosis with right ventricular outflow obstruction
Overriding aorta
Right ventricular hypertrophy
What are the “colours” of the two kinds of shunts?
Left to right- pink
Right to left- blue (cyanotic- skips lungs)
What is TGA?
The aorta arises from the right ventricle
Pulmonary artery arises from the left ventricle
What does post natal development with TGA depend on?
Mixing of outgoing blood (some defect- VSD, PDA, ASD or patent foramen ovale)
What do obstructive lesions within the heart give rise to?
Ventricular hypertrophy without cyanosis
What are the different types of obstructive lesions within the heart?
- Coarctation (constriction) of the aorta- left ventricle hypertrophy
- Pulmonary stenosis and atresia- right ventricle hypertrophy
- Aortic stenosis and atresia
What are the forms of aorta coarctation?
- Infantile- narrowing proximal to PDA, right to left shunting
- Adult- narrowing opposite the (closed) ligamentum arteriosum
What are the types of aortic stenosis and atresia?
Valvular
Hypoplastic left heart syndrome
Subaortic stenosis- ring of fibrous tissue below the cusps
Supraventricular aortic stenosis- elastin gene mutation
What causes ischemic heart disease?
Reduced coronary blood flow (atherosclerosis, vasospasm, thrombosis)
Increased myocardial demand (tachycardia and hypertrophy)
Hypoxia
What syndromes are associated with ischemic heart disease?
Angina pectoris- chest pain
Myocardial infarction- cell death (vascular occlusion)
Chronic ischemic heart disease- progressive heart failure
Sudden cardiac death- lethal arrhythmia
What are the types of angina pectoris?
- Stable- occurs with exertion, diminishes with rest
- Prinzmetal- vasospasm
- Unstable/crescendo- occurs with successively lesser amounts of exertion
What causes most myocardial infarctions?
Atherosclerotic plaques
When is complete necrosis seen in myocardial infarction?
After 6hrs of severe ischemia
What do the morphological features of acute MI depend on?
Location, severity, rate of obstruction development
Size of vascular bed perfused by obstructed vessels
Occlusion duration
Metabolic and oxygen needs of the myocardium
Extent of collateral blood vessels
Presence, site and severity of coronary arterial spasm
Heart rate, cardiac rhythm, blood oxygenation