Cardiac Arrhythmias

Question 1

What does the P wave represent?

Answer 1

Atrial depolarization

Question 2

What is the PR interval?

Answer 2

P-R interval: atrio-ventricular conduction time) normal P-R intervals range between 120 and 200 milliseconds, occasionally being shorter in children and slightly longer in the aged. The P-R interval decreases with increased heart rate (due to exercise or fever) and increases at lower heart rates (sleep).

Question 3

What is the QRS complex?

Answer 3

contraction of the ventricles. Ventricular depolarization. shape of the QRS complex may be modified by a number of physiological factors (e.g. body position and breathing pattern). adults, the duration of the QRS complex varies between 60 and 100 milliseconds; in children it tends to be shorter.

Question 4

What is the QT interval?

Answer 4

beginning of the QRS complex to the end of the T-wave represents the time between activation of electrical activity in the ventricles and return to the resting state. Ventricles are contracting and emptying. Like the P-R interval, the Q-T interval shortens at increased heart rates and increases at lower rates.

Question 5

What is the T wave?

Answer 5

when the electrical activity associated with the cells in the cardiac ventricle returns to the resting state after electrical activation. It signals the start of relaxation of the ventricle walls. Repolarization It tends to be longer lasting than QRS because the onset of relaxation across the ventricle is less tightly synchronized than that of contraction.

Question 6

What is an arrhythmia?

Answer 6

any change from the normal sequence of electrical impulses. The electrical impulses may happen too fast, too slowly, or erratically – causing the heart to beat too fast, too slowly, or erratically

Question 7

What is the prevalence of arrhythmia?

Answer 7

Adults over 65yrs old have an arrhythmia 12.6% of the time. most common arrhythmia is atrial fibrillation. Arrhythmias can cause death, patient may need pacemaker

Question 8

What are signs and symptoms of an arrhythmia?

Answer 8

May have no S & S and are diagnosed routinely Noticeable symptoms: heart fluttering, tachycardia, bradycardia, chest pain, shortness of breath, dizziness, sweating, syncope.

Question 9

What types of dental precautions do you need to take for a patient with a cardiac arrhythmia?

Answer 9

Know type of arrhythmia, signs and symptoms are of their arrythmia, and if they use any blood thinners Obtain medical consult prior to therapy if patient has atrial fibrillation and is being treated with Coumadin Keep patient anxiety and stress to a minimum, and use sedation for stressful procedures Short morning appointments Avoid excessive epinephrine; AVOID vasoconstrictors in patients taking Digoxin Use caution with electrical equipment in patients with pacemakers (electro-surgery, ultrasonic bath or cleaner, and battery operated curing light). ADA states that you should consult the cardiologist before using.

Question 10

Answer 10

Normal sinus rhythm

Question 11

Answer 11

Sinus arrhythmia

Heart rate changes with respirations

Common finding in healthy young people

May sound like a fib on monitor

Normal QRS and P wave, just an irregular rhythm

Question 12

Answer 12

Sinus tachycardia

Electrical impulses originate from SA node at a rate of 101-180 BPM

Etiology: anxiety, fever, pain, acute anemia, hemorrhage, sudden excitement, hyperthyroid, hypoxia, infection

drugs: atropine, nicotine, caffeine, amphetamine

Normal ECG just faster

Can become problematic if patient has poor cardiac output (stroke volume x heart rate)

Question 13

Answer 13

Dysrhythmia that occurs when all electrical impulses originate from the SA node but at a rate of slower than 60 impulses per minute.

Common in athletes and young adults.

Etiology: vomiting, vasovagal syncope, myxedema, increased intracranial pressure, intracranial tumor, hypothermia, gram-negative sepsis, and/or drugs such as lithium, B-blockers, Ca²⁺-channel blockers, morphine, and sedatives.

40-59 BPM

May become dangerous if patient shows poor signs of cardiac output

Question 14

Answer 14

A fibb

Dysrhythmia originating from many atrial sites

Atria makes ineffective quivering movements without any actual contractions, only the ventricles contract

Rapid atrial rate of 350-600 BPM

Regularly irregular

No P waves

Question 15

What are some complications of atrial fibrillation?

Answer 15

1 complication is formation of an embolus/thrombus

Thrombus formation may lead to stroke!

Also, poor impulse generation from atria can cause irregular ventricular rhythms which can cause failure of the pumping action of the heart, the blood will back up into the lungs, and the patient will have congestive heart failure

Question 16

What are typical treatment options for a fibb?

Answer 16

Catheter ablation

Anti-arrythmic drugs: sotalol, procainamide, flecainide, amiodarone (convert to sinus rhythm and maintain)

Digoxin - typically prescribed to CHF patients, but can slow conduction through AV node and slow heart rate

CCBs

Beta-blockers - slow conduction through AV node

Anticoagulants

Question 17

Verbally describe what A fibb looks like on a monitor

Answer 17

Absence of P wave is the **hallmark feature**

P wave is seen as a wavy line instead

Normal QRS complex

Regularly irregular rhythm

Question 18

Answer 18

Atrial flutter

Flutter waves are present instead of P waves

SAW-TOOTH FLUTTER WAVES

atrial rate 250-35- beats/min

normal QRS

rhythm is usually regular, but can be irregular

Question 19

Would you rather have Afibb or atrial flutter?

Answer 19

Flutter is more serious

Question 20

Answer 20

Paroxysmal atrial tachycardia

Paroxysmal tachycardia can arise fro atria, AV node, ventricles

Paroxysmal VENTRICULAR tachycardia is VERY SERIOUS (QRs complexes are wide)

Dangerous condition

high rate of 160-250

P wave morphology usually varies

normal QRS

PR interval may be variable

Question 21

What are treatment options for ventricular tachycardia?

Answer 21

Lidocaine and amiodarone

Recurrent - digitalis, beta blockers, CCBs

supraventriculat - adenosine

Question 22

what is a PVC?

Answer 22

premature ventricular contraction

premature ventricular beat (extra systole)

ectopic beat - the most common form of arrhythmia

Question 23

What is the etiology of a PVC?

Answer 23

Anxiety

hight levels of adrenaleine (caffeine, exercise)

cocaine, amphetamines, alcohol

Digoxin, sympathomimetics, TCAs, and aminophylline have known to be triggers

Question 24

When are PVCs ominous?

Answer 24

4-6 per minute or 3 in a row (triplet)

During a premature ventricular contraction (PVC), the heartbeat is initiated by the Purkinje fibers rather than the SA node. Given that a PVC occurs before a regular heartbeat, there is a pause before the next regular heartbeat. PVCs can occur in isolation or in repeated patterns. Two consecutive PVCs are termed doublets while three consecutive PVCs are named triplets

three or more consecutive PVCs are classified as ventricular tachycardia.

For those with heart disease, PVCs are an indicator of increased mortality risk.[13]

Question 25

what is the normal pathway of electrical activity in the heart?

Answer 25

Regular heartbeats occur when specialized cells in the right atrium of the heart, called the sinoatrial (SA) node, conduct an electrical signal down to the atrioventricular (AV) node which is another set of specialized cells. This electrical signal then works its way down the bundle of His and Purkinje fibers to the heart ventricles. The result is the contraction of the ventricles and pumping of blood from the heart out to the body’s arteries.[1]

Question 26

descrive to me what a PVC looks like on a monitor?

Answer 26

p wave is usually onscured by the QRS, PST, or T wave of the PVC

QRS complex is wide > 0. 12 seconds,

ST segment and T wave will be opposit in polarity

irregular rhythm

Question 27

Answer 27

Ventricular tachycardia

Question 28

What is V tach? What is the etiology? What is the treatment?

Answer 28

Dysrthynmia that originates from a single site from the ventricles

ALmost always occurs in diseased hearts

Rapid heart rate with wide and bizzare QRS complexes

needs defibrillator if pulse is absent

Question 29

what is the difference between v tach and v fibb?

Answer 29

ventricular tachycardia continues to make the heartbeat regularly, but it goes so fast that the heart never gets a chance to fill with blood. There’s not an opportunity to build up the pressure, so the blood stops flowing.

During ventricular fibrillation, the heart stops beating normally and simply begins quivering uncontrollably.

both can be considered lethal dysrhyhmias

Question 30

What is the treatment for V fibb?

Answer 30

Patients in V fibb will have no pulse and are in cardiac arrest

Perform CPR - highest priority is getting these patients atttached to an AED

do not delay defibrillation

epi can be used IV (1 mg every 3-5 minutes)

epi will maintain coronary artery bloof flow while CPR preserves the blood flow to the brain

Question 31

Answer 31

V fibb