Chp.5 Arrhythmias

Under normal conditions the SA node is responsible for doing what in the heart?

Impulse formation

Are capable not only of delivering a shock but of providing antitachycardia pacing (ATP) and ventricular bradycardia pacing

Implantable Cardioverter Defibrillators

Classified on the basis of their effect on sodium, potassium, or calcium channels and whether they block beta receptors

Antiarrhythmic drugs

Patients with atrial fibrillation often are given what kind of therapy to prevent thrombus formation, embolism, and stroke. And are at increased risk for bleeding?

Anticoagulation therapy (Warfarin)

Any tachycardia arising above the Atrioventricular junction for which the ECG shows a P wave configuration different from that for sinus rhythm.

Atrial Tachycardia

Characterized by a rapid disorganized and ineffective atrial contractions that occur at a rate of 350 to 600 beats per minute

Atrial fibrillation

What's the most common type of persistent arrhythmia?

Atrial fibrillation

Characterized by a rapid regular atrial rate of 250 to 350 beats per minute

Atrial flutter

A disturbance of impulse conduction that may be permanent or transient depending on the underlying anatomic or functional impairment

Atrioventricular (AV) Block

Sinus node disturbance defined as a heart rate less than 60 beats per minute with otherwise normal ECG

Bradycardia

Refers to any variation in the normal heartbeat which includes disturbances in rhythm, rate, and conduction pattern of the heart.

Cardiac arrhythmia

Antiarrhythmic drugs that work primarily by blocking the fast sodium channels

Class 1

Antiarrhythmic drugs that are B-adrenergic blocking agents

Class 2

Antiarrhythmic drugs that prolong duration of the cardiac action potential and enhance refractoriness through their effects on potassium channels

Class 3

Antiarrhythmic drugs that are calcium channel blockers

Class 4

Patients with atrial fibrillation may be taking the newer anticoagulant to prevent thrombus formation embolism and stroke and is said to cause no increase in major bleeding

Dabigatran (Pradaxa)

What is the primary tool used to identify cardiac arrhythmias

ECG

Treatment of atrial flutter or Atrial fibrillation is usually what?

Elective

Treatment of Ventricular Tachycardia can be what?

Elective or emergent

Treatment of Ventricular fibrillation is always what

Emergent

Heart block degree when conduction time is prolonged, but all impulses are conducted?

First degree

Whats a rare complication of pacemaker placement

Infective endocarditis

Disorder of the conduction system in which the recharging of the heart during repolarization is delayed. Caused by a genetic mutation in myocardial ion channels and by certain drugs?

Long QT syndrome

Is Antibiotic prophylaxis indicated for patients with pacemakers or ICD's

NO

Should you use a gingival retraction cord in patients with cardiac arrhythmias?

NO

Sinus node disturbance where unrelated to respiratory effort and seen with digitalis intoxication

Nonrespiration

consists of lithium battery powered generator implanted subcutaneously in the left infraclavicular area that produces an electrical impulse

Permanent implanted pacemaker

Impulse arising from ectopic foci anywhere in the atrium may result in premature atrial beats

Premature atrial complexes

Premature occurrence of an abnormally shaped QRS complex followed by a pause.

Premature ventricular complexes

Technique where a catheter is introduced percutaneously into a vein and is threaded into the heart.

Radiofrequency Catheter Ablation

What occurs when accessory or ectopic pacemakers re excite previously depolarized fibers before they would become depolarized in the normal sequential impulse pathway typically producing tachyarrhythmia

Reentry arrhythmias

Sinus node disturbance where heart rate increases with inhalation and decreases with exhalation

Respiratory

What regulates the functions of the atria and is responsible for the production of the P wave(atrial depolarization) of the ECG. Simultaneous depolarization of the ventricles produces the QRS complex on the ECG?

SA Node

What is the primary anatomic pacemaker for the heart is the what?

Sinoatrial node (SA) node

Phasic variation in sinus cycle length?

Sinus arrhythmia

Arrhythmias are classified by?

Site of orgin

What can Long QT syndrome cause?

Syncope, seizure, sudden death

Supraventricular cardiac arrhythmias may be broadly categorized into what two things?

Tachyarrhythmia and Bradyarrhythmias

Sinus node disturbance when heart rate greater than 100 beats per minute with otherwise normal ECG

Tachycardia

Degree of heart block where no impulses are conducted

Third degree

Second degree heart block characterized by progressive lengthening of conduction time until an impulse is not conducted

Type 1

Second degree heart block occasional or repetitive sudden block of conduction of an impulse without previous lengthening of conduction time

Type 2

What in a dental office can cause an electromagnetic interference to a pacemaker or ICD?

Ultrasconic

Lethal arrhythmias characterized by chaotic disorganized electrical activity that results in failure of sequential cardiac contraction and inability to maintain cardiac output

Ventricular flutter and fibrillation

The occurrence of the three or more ectopic ventricular beats at a rate of 100 or more per minute is defined as ventricular tachycardia

Ventricular tachycardia

Additional electrical bridges connect the atria and ventricles bypassing the normal pathways and forming the basis for preexcitation syndrome called?

Wolff-Parkinson White syndrome

Normal cardiac function depends on what 4 things?

cellular automaticity, conductivity, excitability, and contractility

Signs of Toxicity include

hypersalivation, nausea, drowsiness, visual distortions

To manage arrhymias more than 500,000 people in North America have what?

implanted pacemakers

What two things effect the outcome of the arrhythmia?

nature of the arrhythmia and the physical condition of the patient

What two things could lead to life threatening cardiac arrhythmias in a dental office?

stress and large amounts of injected epinephrine

Any arrhythmia that arises above the bifurcation of the HIS bundle into the right and left bundle branches is classified as what?

supraventricular

Many antiarrhythmic drugs have very narrow

therapeutic ranges

If vasoconstrictor is necessary for patients with low to intermediate risk of cardiac arrhythmias how much should they receive?

two cartridges containing 1:100,000 epinephrine (intravascular injections should be avoided)