Cardiac arhythmias- Exam 2

Question 1

What caused tachycardia?

Answer 1

Increased body temperature
Sympathetic stimulation of the heart
Toxic condition of the heart resulting in weakening of the myocardium

Question 2

What are the events during endogenous mediated tachycardia (exercise)

Answer 2

Heart rate increases
Cardiac output increases
Filling time reduce but stroke volume remain the same.

Question 3

Explanation of events during endogenous mediated tachycardia

Answer 3

Sympathetic stimulation to the heart increase contractility and helps maintain stroke volume.
Systolic interval reduced allowing more diastole filling time
Sympathetic stimulation and skeletal muscle increase venous return to help maintain ventricular filling.

Question 4

Events during pathologically mediated tachycardia

Answer 4

Heart rate increases

cardiac output decreases

Question 5

Explanations of events during pathologically mediated tachycardia

Answer 5

Mean atrial pressure decreases and activates the sympathetic nervous system which occurs after the fact and is unable to compensate.
No muscle pump to increase venous return

Question 6

What is bradycardia?

Answer 6

Slow rate (

Question 7

What caused bradycardia?

Answer 7

Athletic heart
Vagal stimulation
extremely sensitive carotid baroreceptors in carotid sinus syndrome

Question 8

What are spillover signals?

Answer 8

Signals caused by breathing rate that can affect heart rate.

Alternately increase and decrease number of impulses transmitted through sympathetic and vagus nerves to the heart

Question 9

Characteristics of sinoatrial block

Answer 9

Sudden cessation of P waves
No signal in the atrial myocardia
stand still of atria
ventricles pick up new rhythm  in AV node
rate of QRS slowed but not altered

Question 10

What are the conditions causing atrioventricular block?

Answer 10

Ischemia of AV node or AV bundle fibers through coronary insufficiency.
Compression of Av bundle by scar tissue or calcified portion of the heart.
Inflammation of the AV node or AV bundle
Extreme stimulation of the heart by vagus nerves

Question 11

Characteristics of first degree incomplete AV block

Answer 11

PR interval increases to 0.20 seconds

Question 12

Characteristics of 2nd degree incomplete AV block

Answer 12

PR interval increases to 0.25 seconds to 0.45 seconds
P wave present but QRS wave may be missing
Drop beats in ventricle
2:1 rhythm may develop

Question 13

Characteristics of complete (3rd degree) AV block

Answer 13

Ventricles establish own signal (AV node)
No relation between rate of P wave and QRST complex
Duration of block variable (seconds to weeks)
ventricles may not start beating on their own for 5-30 seconds after AV conduction.

Question 14

What is a ventricular escape?

Answer 14

Resumption of ventricular beat due o part of the Purkinje system being an ectopic pacemaker in complete AV block

Question 15

What is Stokes Adams syndrome?

Answer 15

Periodic fainting spells due to lack of blood to the brain until ventricular escape in patient with a complete AV block

Question 16

Characteristics of partial intraventricular block

Answer 16

Referred to as electrical alternans

Alternation in the amplitude of P waves, QRS complex and T waves

Question 17

Characteristics of premature contractions

Answer 17

Contraction that occur before they should

Result of ectopic foci like local ischemic areas, calcified plaques, irritation of the conduction system or nodes

Question 18

Characteristics of paroxysmal tachycardia.

Answer 18

Heart comes rapid in paroxysms
Begin suddenly and duration is variable
End suddenly due to pacemaker of the heart instantly shifting back to the sinus node.

Question 19

What is fibrillation?

Answer 19

Twitching of individual muscle fibers in the atria or ventricles and also in recently denervated skeletal muscle fibers.
Occurs as a result of circus movements

Question 20

What are the conditions of circus movements?

Answer 20

Pathway around the circle is too long
Length of the pathway constant but velocity of conduction slows down.
Refractory period of the muscle greatly shortened

Question 21

Characteristics of atrial fibrillation

Answer 21

Can occur without ventricular fibrillation
Caused :
by enlargement of the atria (valve lesions)
Inadequate emptying of the ventricles causing blood to back up in the atria.

Question 22

What is tachycardia?

Answer 22

Fast heart rate (> 100 beats/min)