T. Cardiac Dysrhythmias

Question 1

Dysrhythmias

Answer 1

Abnormal cardiac rhythms

Question 2

Automaticity

Answer 2

ability and initiation of an impulse

the property of cardiac cells to generate spontaneous action potentials.

Question 3

Contractility

Answer 3

the way the heart responds to the impulse by contracting

Question 4

Conductivity

Answer 4

how the impulse is transmitted

Question 5

Excitability

Answer 5

the way it’s electrically stimulated

Question 6

Autonomic Nervous System

Answer 6

• controls rate, speed of conduction, strength of contraction

Question 7

Parasympathetic Nervous System

Answer 7

• decrease rate, slow conduction and decrease force of contraction
• Stimulation of the vagus nerve causes a decreased rate of firing of the SA node and slowed impulse conduction of the AV node

Question 8

Sympathetic Nervous System

Answer 8

• increase rate and force of contraction

* Stimulation of the sympathetic nerves increases SA node firing, AV node impulse conduction, and cardiac contractility

Question 9

Electrocardiogram

Answer 9

Measure the heart’s electrical activity as waveforms.
Each beat is seen through one wave

PQRST = 1 heart beat

Question 10

Depolarization/

Repolarization

Answer 10

Depolarization makes the inside of the cell + due to movement of Na

Repolarization makes the inside negative again

Question 11

12 Lead EKG

Answer 11

• Six leads measure electrical forces in the frontal plane.

* Six leads measure electrical forces in the horizontal plane (precordial leads).

Question 12

Normal Sinus Rhythm

Answer 12

• the rhythm of a healthy heart
• Sinus node fires 60–100 bpm.
• Follows normal conduction pattern

Question 13

QT interval

Answer 13

• Represents total time required for ventricular depolarization and repolarization
• represents the absence of electrical activity in heart

Question 14

P wave

Answer 14

Atrial depolarization

• defects often due to atria enlargement

Question 15

PR Segment

Answer 15

Electrical impulse traveling through atrioventricular (AV) node

Question 16

QRS complex

Answer 16

Ventricular depolarization

Question 17

T wave

Answer 17

Ventricular repolarization

• inverted T wave in myocardial damage

Question 18

Sinus Bradycardia

Answer 18

Cardiac Arrhythmias

• Slow but regular heart rate because sinus node discharges at rate <60 beats per minutes
• Can be normal, especially in athletes
• Hypothyroidism also causes SB
• The PR interval is normal, and the QRS complex has a normal shape and duration.

Treatment
Atropine (muscle relaxant)
Pacemaker may be required

Question 19

Sinus Tachycardia

Answer 19

Cardiac Arrhythmias

• Fast but regular heart rate because sinus node discharges at rate >100 beats per minutes
• Normal in response to stress, exercise, fever, pain, anxiety.ª«
• The PR interval is normal, and the QRS complex has a normal shape and duration.

Treatment

• Determined by underlying cause
• ß-adrenergic blockers to reduce HR and myocardial oxygen consumption
• Antipyretics to treat fever
• Analgesics to treat pain

Question 20

Arrhythmias

Answer 20

a problem with the rate or rhythm of your heartbeat. It means that your heart beats too quickly, too slowly, or with an irregular pattern.

Question 21

Atrial Flutter

Answer 21

Cardiac Dysrythmias

• Atria of heart contracting rapidly in characteristic flutter waves
• 1 ventrible beat for evey 4 atrial
• Atria rate is 250 -350 beats/minute. The ventricular rate varies according to the conduction rate.
• Seldom normal
• Saw tooth waves are regular.

Treatment
• Primary goal is to slow ventricular response by increasing AV block

• High ventricular rates (>100) and loss of the atrial “kick” can decrease CO and precipitate HF, angina
• Risk for stroke due to risk of thrombus formation in the atria

Question 22

Atrial Fibrillation

Answer 22

Cardiac Dysrhythmias

• Total disorganization of atrial electrical activity due to multiple ectopic foci, resulting in loss of effective atrial contraction
• Can result in decrease in CO due to ineffective atrial contractions (loss of atrial kick) and rapid ventricular response
• Thrombi may form in the atria as a result of blood stasis.

Tr4eatment:

• Decrease ventricular rate.
• Prevent cerebral embolic events.

Question 23

Junctional Dysrhythmias

Answer 23

Dysrhythmias that originate in area of AV node

SA node has failed to fire, or impulse has been blocked at the AV node.

Question 24

Premature Ventricular Contractions

Answer 24

• Contraction originating in ectopic focus of the ventricles
• Premature occurrence of a wide and distorted QRS complex
• Can be Multifocal, unifocal, ventricular bigeminy, ventricular trigeminy, couples, triplets, R-on-T phenomena
> Multifocal – happen may time in a row
> Unifocal – happen evey now and then
> Ventricular bigeminy – have 2 in a row
> Ventricular trigeminy – have 3 in a row
> Couples – always happen in pairs of 2
> Triplets – always happens in pairs of 3

Question 25

Ventricular Tachycardia

Answer 25

• It occurs when the lower chamber of the heart beats too fast to pump well and the body doesn’t receive enough oxygenated blood.
• Ventricular rate 100 to 250 beats per minute
• Run of three or move PVC’s
• Life threatening
• Treatment for VT must be rapid

Question 26

Ventricular Fibrillation

Answer 26

• Ventricles quivering so no cardiac output
• Disorganized ventricle electrical activity without coordination and without effective contractions ineffective “quivering’ of ventricles
• If untreated leads to death
• Unresponsive, pulseless, and apneic state
• Cant differentiate any of the waves of EKG

Question 27

Asystole

Answer 27

• Absence of contractions of the heart
• Flat line in an EKG
• seen in end-stage HF, advanced cardiac disease

Question 28

Syncope

Answer 28

Brief lapse in consciousness accompanied by a loss in postural tone (fainting)

Question 29

Ischemia EKG

Answer 29

ST segment depression and/or T wave inversion

• Changes occur in response to the electrical disturbance in myocardial cells due to inadequate supply of oxygen.
• Once treated (adequate blood flow is restored), ECG changes resolve and ECG returns to baseline.