Disorders of the Heart

avenue for electrical signals to pass from atria to ventricles

Bundle of His

what is unique about myocyte structure

cells are fused electrically

uniqueness of myocardial contraction

it is all or nothing and cells contract in unison

cardiac valves ensure _

one way flow

which part of the heart muscle is last to be supplied

subendocardial muscle

which part of the heart is most vulnerable to ischemia

subendocardial muscle

structure of coronary arteries

have few branches

coronary arteries are incapable of _ due to their lack of branching

supplying or receiving significant collateral flow when obstructed

cardiac conduction system pathway

1. SA node

2. signal passes through atria

3. AV node

4. bundle of His

5. bundle branches to apex

6. purkinje fibers

2 ways that heart disease manifests

decreased cardiac output

increased effort to maintain output

5 mechanisms of heart disease

1. heart failure

2. coronary artery disease

3. valvular disease

4. shunts

5. conduction issues (arrhythmias)

things associated with heart failure

lack of cardiac muscle power

reduced blood flow

dilation

2 types of valvular disease

stenosis

regurgitation

what defines congestive heart failure

inability for the heart to meet metabolic demand

compensated failure

ventricle dilation causes more forceful contraction

uncompensated heart failure

ventricle dilation causes LESS forceful contraction

causes of LVF

MI

HTN

valvular disease

myocarditis

cardiomyopathy

forward effect of LVF

low flow, hypoxia, organ failure

backward effect of LVF

pulmonary congestion

edema

causes of right ventricular failure

left heart failure

valvular disease

cor pulmonale

cor pulmonale

lung disease leading to heart disease

forward effect of RVF

low pulmonary perfusion

backward effect of RVF

venous congestion (chronic passivve congestion)

hepatomegaly, splenomegaly

edema

systolic HF

decreased stroke volume

diastolic heart failure

impaired filling, stiff or deceased muscle

clinical findings of HF

dyspnea

peripheral pitting edema

cyanosis

main treatments for CHF

weight loss

sodium restriction

cardiac drugs

prognosis of CHF

poor unless the cause of CHF is correctable

obstructed coronary blood flow causes _

myocardial ischemia/infarction

main cause of coronary artery disease

atherosclerosis

which type of atheroma is more likely to hemorrhage and cause infarct

young atheroma

acute ischemia effects

angina

MI

stable angina

responds to medications and rest

unstable angina

unremitting and may precede an MI

what defines a myocardial infarction

circumscribed area of muscle necrosis

most common cause of MI

ischemia downstream of an atheromatous plaque rupture

most commonly obstructed coronary artery

left anterior descending artery

_ should be suspected in adults with chest pain

coronary artery disease

CAD findings on ECG

inverted T waves

STEMI or NSTEMI

blood finding of CAD

cardiac troponin

3 things that CAD drugs aim to do:

dissolve thrombus

reduce cardiac workload

control arrhythmias

what does catheterization achieve

thrombolysis

stent placement

complications of CAD

arrhythmia

HF

shock

embolism

cardiomyopathy

most common cause of valve disease

degeneration

3 causes of valvular disease

degeneration (most common)

rheumatic fever

endocarditis

rheumatic fever most commonly affects which heart valve

mitral valve (stenosis)

types of endocarditis

infectious / non-infective thrombotic

how does myocarditis present

dyspnea

arrythmias

HF

usual cause of myocarditis

virus (Coxsackie A or B)

non-inflammatory intrinsic diseases of cardiac muscle

cardiomyopathies

how does cardiomyopathy manifest

ventricular dysfunction

types of cardiomyopathy

dilated

hypertrophic

restrictive

most common type of cardiomyopathy

dilated

causes of dilated cardiomyopathy

chronic ischemic heart disease

examples of secondary cardiomyopathy

chronic ischemic heart disease

LVH

effect of ventricular hypertrophy

reduced blood filling

reduced pumping

increase pericardial fluid

pericardial effusion

causes of pericardial effusion

inflammation

metastases

HF

trauma

hemopericardium may lead to _

cardiac tamponade

obstructive shock

causes of hemopericardium

trauma

aortic dissection

causes of pericarditis

dressler syndrome

infection

renal disease

dressler syndrome is associated with what disease?

pericarditis

right to left shunts are _

cyanotic

left to right shunts are _

non-cyanotic

example of left to right shunt

atrial or ventricular septal defect

persistent ductus arteriosus

example of right to left shunt

tetralogy of fallot

tetralogy of fallot is what type of shunt

right to left

_ is more common than primary tumors of the heart

metastatic cancer

most common primary heart tumor

atrial myxoma

atrial myxoma may lead to _

embolization → stroke

is atrial myxoma benign or malignant

benign

is atrial fibrillation or flutter more common

fibrillation

risk associated with A-fib and flutter

thromboembolism leading to stroke

benign ventricular arryhtmia

PVCs

dangerous ventricular arrhythmias

Vtach

Vfib

V-tach can lead to _

sudden cardiac arrest

most fatal arrythmia

ventricular fibrillation

atrial fibrillation produces _

very rapid irregular ventricular beats