Cardiac Dysrythmias And Valvular Disorders

Question 1

Nodal cells

Answer 1

Self-excitability
Spontaneously and rythmically generate action potentials
Regulated by:
-potassium
- sodium
- calcium

Question 2

ECG tracing

Answer 2

P wave - atrial depolarization
PR - movement of electrical impulse between atria and ventricles
QRS - ventricular depolarization
ST - atrial repolarization
T wave - ventricular repolarization

Question 3

Dysrhythmias

Answer 3

An abnormality of the rhythm of the heartbeat
Caused by:
- O2 deprivation
- disturbance in impulse formation
- disturbance in impulse conduction

Question 4

Tachydysrythmias (sinus tachycardia)

Answer 4

HR increased
Respond best to pharmacological intervention
Sympathetic activation
Often compensatory response to inc demand for cardiac output or reduced SV

Question 5

Bradydystrythmia (sinus bradycardia)

Answer 5

HR decreased
Tx with electronic pacing or medications
Parasympathetic activity

Question 6

Heart block

Answer 6

Conduction impulses are blocked often at AV junction
Tx: pacemaker or correction of cause

Question 7

PVC

Answer 7

Premature ventricular complex, when the SA node takes too long to initiate a beat
Extra beat, skip a beat, flip-flop
Very common
Tx: not normally needed

Question 8

A fib

Answer 8

Irregular, rapid heart rate
Causes poor blood flow to the body
Atria beat chaotically and irregularly
S/S: hear palpitations, SOB, weakness
Not life-threatening if alone, but can cause complications like stroke and Dec CO

Tx: digoxin, Na channel blockers, beta blockers, or Ca channel blockers
Pacemaker
Synchronized cardioversion

Question 9

V fib

Answer 9

VT - regular heart rhythm that originates in the lower chambers of the heart
VF - abnormal heart rhythm that is disorganized and irregular

Sudden onset and sudden death

Tx:
VT - synchronized cardioversion
VF or pulseless VT - defibrillation shock or lidocaine IV

Question 10

Wolff-Parkinson-White Syndrome

Answer 10

Additional pathways (accessory pathway) which directly connects the atria and ventricles, thereby allowing electrical activity to bypass the AV node

S/S: mild palpitations, syncope, intermittent tachycardia

Tx: catheter mediated radio frequency ablation is the preferred non-pharmacological treatment

Question 11

Valves of heart (in order of what blood goes through)

Answer 11

Tricuspid —> pulmonic —> bicuspid (mitral) —> aortic

Question 12

Stenosis

Answer 12

The valve orifice is constricted and narrowed so blood cannot flow forward and the workload of the cardiac chamber proximal to the diseased valve increases

Question 13

Regurgitation

Answer 13

Valve leaflet, or cusps, fail to shut completely, permitting blood flow to continue even when the valve is presumably closed

During systole or diastole some blood leaks back into the chamber proximal to the diseased valve, which increases the volume of blood the heart must pump and increases the workload of both atrium and ventricle

Question 14

Aortic Valve Stenosis

Answer 14

Aortic valve degeneration with aging is associated with chronic inflammation, lipoprotein deposition in the tissue, and leaflet calcification

Leads to poor perfusion, not enough blood getting pumped through body

Question 15

Mitral valve stenosis

Answer 15

Impairs the flow of blood from the left atrium to the left ventricle

Incomplete emptying of the left atrium and elevated atrial pressure as the chamber tries to force blood through the stenotic valve

Atrial dilation and hypertrophy leads to thrombi and dysrythmias

Question 16

Aortic valve regurgitation

Answer 16

Inability of the aortic valve to close properly during diastole because of abnormalities of the leaflets

During systole, blood is ejected from L ventricle into aorta
During diastole, ejected blood flows back into the L ventricle through the leaking valve

Ventricular dilation and hypertrophy and leads to HF

Question 17

Mitral valve regurgitation

Answer 17

Permits backflow of blood from the L ventricle into the L atrium during ventricular systole

Murmur heard best at apex

L ventricle becomes dilated and hypertrophied to maintain adequate CO

The volume of backflow re-entering the left atrium gradually increases, causing a fib