Term
| What are cardiac arrhythmias? |
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Definition
| any variation in the normal heartbeat, includes disturbances in rhythm, rate, or the conduction pattern of the heart |
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Term
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Definition
| can range anywhere from of little concern to life threatening |
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Term
| What can potentially fatal arrhythmias can be precipitated by? |
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Definition
| strong emotion, such as anxiety or anger, and by various drugs, both of which are factors likely to be encountered in the dental setting |
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Term
| What is the most common type of arrhythmia? |
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Definition
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Term
| What is a common way to manage arrhythmias? |
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Definition
| by getting a pace maker put in |
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Term
| What are cardiac contractions caused by? |
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Definition
| a complex system of specialized excitatory and conductive neuronal circuitry |
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Term
| What is The normal pattern of sequential depolarization involves structures of the heart? (5) |
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Definition
1.Sinoatrial (SA) node
2.Atrioventricular node (AV) node
3.Bundle of His
4.Right and left bundle branches
5.Subendocardial Purkinje network |
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Term
| What is the primary anatomic pacemaker for the heart? |
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Definition
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Term
| What is responsible for the P wave (atrial depolarization) of the ECG? |
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Definition
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Term
| What is the t wave formed by? |
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Definition
| repolarization of the ventricles, occurs at same time as depolarization |
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Term
| What does normal cardiac function depend on?(4) |
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Definition
1.cellular automaticity(impulse formation)
2.conductivity
3.excitability
4.contractility |
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Term
| Under normal conditions, what is responsible for impulse formation? |
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Definition
| the SA node, but other cells are capable of generating impulses too |
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Term
| What can Disorders of conductivity (block or delay) paradoxically lead to? |
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Definition
| may lead to rapid cardiac rhythm through the mechanisms of reentry |
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Term
| When do Reentry arrhythmias occur? |
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Definition
| occur when accessory or ectopic pacemakers re-excite previously depolarized fibers before they would become depolarized in the normal sequential impulse pathway |
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Term
| What does this typically form? |
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Definition
| tachyarrhythmias(fast heart beat) |
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Term
| What are the most common causes of arrhythmias? (6) |
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Definition
1.Primary cardiovascular disorders
2.Pulmonary disorders (e.g., embolism, hypoxia)
3.Autonomic disorders
4.Systemic disorders (e.g., thyroid disease)
5.Drug-related adverse effects
6.Electrolyte imbalances |
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Term
| What does the outcome of an arrhythmia depend on? |
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Definition
| the nature of the arrhythmia and the health of the patient |
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Term
| What are arrhythemias classified by? |
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Definition
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Term
| Where is the location of a supraventricular arrhythmia? |
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Definition
| Any arrhythmia that arises above the bifurcation of the His bundle into right and left bundle branches |
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Term
| What are some supraventricular arrhythemias? (6) |
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Definition
1.Sinus node disturbances
2.Disturbances of atrial rhythm
3.Tachycardias involving the AV junction
4.Heart block
5.Ventricular arrhythmias
6.Disorders of repolarization |
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Term
| What is a sinus arrhythmia characterized by? |
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Definition
-characterized by phasic variation in sinus cycle length
-respiratory(BPM increases with inhalation and decreases with exhalation)
-nonrespiratory(not related to respiratory, seen in digitalis intoxication) |
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Term
| What is sinus tachycardia characterized by? Bradycardia? |
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Definition
tachycardia- greater than 100 BPM
bradycardia-less than 60 bpm
**both with otherwise normal ECG** |
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Term
| What are Premature atrial complexes? |
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Definition
| Impulses arising from ectopic foci anywhere in the atrium may result in premature atrial beats |
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Term
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Definition
| Characterized by a rapid, regular atrial rate of 250 to 350 beats per minute |
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Term
| What is atrial fibrillation? |
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Definition
| Characterized by rapid, disorganized, and ineffective atrial contractions that occur at a rate of 350 to 600 beats per minute |
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Term
| What is atrial tachycardia? |
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Definition
| Any tachycardia arising above the AV junction for which the ECG shows a P wave configuration different from that for sinus rhythm |
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Term
| What is Preexcitation syndrome (e.g., Wolff-Parkinson-White syndrome)? |
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Definition
| In some persons, additional electrical bridges connect the atria and ventricles, bypassing the normal pathways and forming the basis for preexcitation syndromes |
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Term
| What is defined by a disturbance of impulse conduction that may be permanent or transient, depending on the underlying anatomic or functional impairment? |
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Definition
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Term
| How are heart blocks classified? |
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Definition
| by severity(first, second, or third degree) |
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Term
| What is a first degree heart block? |
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Definition
| conduction time is prolonged, but all impulses are conducted |
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Term
| How many forms of second degree heart blocks are there? What are they? |
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Definition
Two:
Type I—characterized by progressive lengthening of conduction time until an impulse is not conducted
Type II—occasional or repetitive sudden block of conduction of an impulse without previous lengthening of conduction time |
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Term
| What is a third degree heart block? |
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Definition
| no impulses are conducted |
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Term
| What are premature ventricular complexes characterized by? |
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Definition
| Characterized by the premature occurrence of an abnormally shaped QRS complex (ventricular contraction), followed by a pause |
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Term
| What is ventricular tachycardia? |
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Definition
| The occurrence of three or more ectopic ventricular beats (PVCs) at a rate of 100 or more per minute |
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Term
| What is ventricular flutter and fibrillation? |
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Definition
| Lethal arrhythmias characterized by chaotic, disorganized electrical activity that results in failure of sequential cardiac contraction and inability to maintain cardiac output |
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Term
| What is a disorder of the conduction system in which the recharging of the heart during repolarization (i.e., the QT interval) is delayed? |
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Definition
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Term
| What is long QT syndrome caused by? What can it lead to? |
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Definition
-Caused by a genetic mutation in myocardial ion channels and by certain drugs, or may be the result of a stroke
-Can lead to fast, chaotic heartbeats, which can trigger unexplained syncope, a seizure, or sudden death |
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Term
| Do arrhythmias have symptoms? Can the presence of symptoms tell us the seriousness of the arrhythmia? |
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Definition
-some have symptoms, others do not
-symptoms along cannot determine seriousness of arrhythmia |
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Term
| What are some common symptoms of arrhythmias? |
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Definition
-palpitations
-lightheadedness
-feeling faint
-syncope
-symptoms related to congestive heart failure |
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Term
| What is the primary tool used in the identification and diagnosis of cardiac arrhythmias? |
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Definition
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Term
| What are Antiarrhythmic drugs are classified on the basis of? |
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Definition
-their effect on sodium, potassium, or calcium channels
-whether they block beta receptors |
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Term
| How do classes I and II work? |
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Definition
I-work primarily by blocking the fast sodium channels
II-β-adrenergic-blocking agents |
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Term
| How do classes III and IV work? |
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Definition
III-prolong duration of the cardiac action potential and enhance refractoriness through their effects on potassium channels
IV-calcium channel blockers |
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Term
| What do many of the antiarrhythmic drugs have? |
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Definition
| a small therapeutic range which means many are undermedicated or overmedicated |
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Term
| What are undermedicated patents at risk for? Overmedicated? |
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Definition
Under-at increased risk for an adverse event during dental treatment
Over-at increased risk for drug toxicity |
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Term
| What kind of battery does a pacemaker have? Where is it? |
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Definition
-lithium
-powered generator implanted subcutaneously in the left infraclavicular area that produces an electrical impulse |
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Term
| What is the impulse created by a pacemaker transmitted by? |
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Definition
| a lead inserted into the heart through the subclavian vein to an electrode in contact with endocardial or myocardial tissue |
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Term
| Are pacemakers individualized? |
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Definition
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Term
| What can rarely occur with a pacemaker? Does this mean that the person needs antibiotics before a dental treatment? |
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Definition
-IE rarely may occur
-antibiotic prophylaxis for dental treatment is not recommended |
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Term
| What are ICD's(Implantable Cardioverter-Defibrillators) capable of? |
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Definition
delivering a shock but of providing antitachycardia pacing (ATP) and ventricular bradycardia pacing
(can terminate rhythm disturbance without shock) |
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Term
| What can temporarily interfere with the function of a pacemaker or ICD? |
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Definition
| Electromagnetic interference (EMI) from nonintrinsic electrical activity |
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Term
| What are some things in the dental office that cause EMI? |
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Definition
-ultrasonic bath cleaners
-ultrasonic scaling devices
-battery-operated curing lights |
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Term
| What is a technique whereby a catheter (electrode) is introduced percutaneously into a vein and is threaded into the heart? |
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Definition
| Radiofrequency Catheter Ablation(put where arrhythmia is and destroys ectopic pacemaker) |
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Term
| What do direct surgerys to fix arrhythmias consist of? |
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Definition
| consist of resection of tissue and ablation |
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Term
| What are some indirect approaches to surgerys to fix arrhythmias? Who are they for? |
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Definition
| -aneurysmectomy, coronary artery bypass grafting, or relief of valvular regurgitation or stenosis, -may be useful in selected patients |
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Term
| When are Cardioversion and Defibrillation used? |
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Definition
-to fix terminate persistent or refractory arrhythmias
-on an emergency basis
*The shock terminates arrhythmias caused by reentry by simultaneously depolarizing large portions of the atria and ventricles, thereby causing reentry circuits to disappear momentarily |
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Term
| What are the most common arrhythmias treated by cardioversion/defibrillation? |
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Definition
-VF(always emergent)
-VT(may be elective or emergent)
-AF(usually elective)
-atrial flutter(usually elective) |
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Term
| Are patients with severe arrhythmias allowed to have elective dental care? What about others? |
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Definition
-patients with severe arrhythmias are not allowed to have elective dental care
-patients with other types are |
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Term
| What is something simple we can do help calm people with mild to intermediate arrhythmias? |
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Definition
| employ stress reduction strategies |
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Term
How much epinephrine can patients in the low to intermediate risk category and those taking nonselective beta blockers can safely be given?
**if use of vascoconstrictors is necessary** |
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Definition
| given up to 0.036 mg epinephrine (two cartridges containing 1:100,000 epinephrine) |
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Term
| Are vascoconstrictors generally recommended for those with arrhythmias? |
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Definition
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Term
| What are patients with atrial fibrillation often given? |
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Definition
| anticoagulation therapy (warfarin) to prevent thrombus formation, embolism, and stroke |
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Term
| If a patient is taking warfin what are they at chance for? |
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Definition
| at risk for increased bleeding, but can still do up to tooth extractions without having to discontinue use |
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Term
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Definition
| is an oral antithrombin medication that is reported to cause no increase in major bleeding(also used in A fib) |
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Term
| Are patients with pacemakers or ICDs at risk for bacterial endocarditis related to dental procedures? |
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Definition
| No, there for no premedication is needed |
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Term
| What are some signs of Digoxin Toxicity? Why can it so easily occur? |
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Definition
-has a small therapeutic range
-hypersalivation, nausea and vomiting, headache, drowsiness, and visual distortions, with objects appearing yellow or green(refer patient to physician) |
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