Dental Management of Patients with Cardiac Arrhythmias

Dental Management of Patients with Cardiac Arrhythmias
Presentation by:Donald Falace, DMD
Oral Diagnosis and Oral Medicine
UK College of Dentistry

Conduction System of the Heart
* Begins with depolarization of the SA (sinus) node
* Impulse then spreads to the atria resulting in..
* Contraction of atria with blood being pumped out of the atria
* Then the AV node depolarizes and…
* Impulse spreads to the bundle of His and then to right and left bundle branches resulting in…
* Contraction of ventricles and blood being pumped out of the ventricles

Electrocardiogram
* P wave = atrial depolarization
* QRS wave = ventricular depolarization
* T wave = ventricular depolarization
* Atrial depolarization is masked by the QRS wave

Terminology

* Sinus rhythm: normal heart rhythm originating in the SA (sinus) node; 60-100 beats/minute
o Tachycardia: rapid heart rate greater than 100 beats per minute
o Bradycardia: slow heart rate less that 60 beats per minute
* Supraventricular arrhythmias: arrhythmias originating in areas other than the normal ventricular pathways (such as from the atria, AV node, or an accessory pathway)
* Premature ventricular contraction (PVC): a ventricular contraction (QRS wave) not preceded by an atrial contraction (P wave) due to an abnormal electrical focus in the ventricles; found in normal and abnormal patients
* Heart block: an interruption in the normal electrical conduction between the atria and ventricles so that the atria and ventricles beat independently
* Ectopic pacemaker: appearance of a new and abnormal pacemaker
* Fibrillation: a chaotic heart beat

Classification of Arrhythmias
Classified by Site of Origin

o Supraventricular: arrhythmias that arise above the bifurcation of the His bundle (atria) and broadly categorized into
+ Tachyarrhythmias (too fast)
+ Bradyarrhythmias (too slow)
o Ventricular: arise below the bifurcation of the His bundle (ventricles)

Supraventricular Arrhythmias
* Sinus nodal disturbances
o Sinus arrhythmia (resp)
o Sinus tachycardia (>100)
o Sinus bradycardia (<60)
* Disturbances of atrial rhythm
o Premature atrial complexes (ectopic foci)
o Atrial flutter (250-350)
o Atrial fibrillation (350-600)
o Atrial tachycardias (150-200)
* Tachycardias involving the atrioventricular (AV) junction (accessory AV pathways)
o Pre-excitation syndrome (Wolff-Parkinson-White)
* Heart block (conduction impairment)
o First degree
o Second degree
+ Mobitz type I (Wennckebach)
+ Mobitz type II
o Third degree

Ventricular Arrhythmias
* Premature ventricular complexes (PVC’s; very common)
o Occur alone
o Every other (bigeminy)
o Every third (trigeminy)
o Two consecutive (couplet)
o Three consecutive (ventricular tachycardia)
* Ventricular tachycardia
o Three or more PVC’s in a row
* Ventricular fibrillation

Atrial Fibrillation

* Most common sustained arrhythmia
* Rapid, chaotic atrial activity; 350-600 beats per minute
* Disagreeable palpitations or discomfort, weakness, faintness, breathlessness; stroke
* Usually associated with RHD, HBP, IHD, thyrotoxicosis
* May be found in otherwise healthy individuals
* Prone to thromboembolism, therefore, will often be on warfarin

Significance and Risk of Arrhythmias

* ACC/AHA Guideline Update for Perioperative Cardiovascular Risk Evaluation for Non-Cardiac Surgery (Circulation 2002;105:1257-1267)
* Major Risk:
o High grade A-V block
o Symptomatic ventricular arrhythmias in the presence of underlying heart disease
o Supraventricular arrhythmias with uncontrolled ventricular rate
* Intermediate Risk:
o Abnormal Q waves (marker of previous MI)
* Minor Risk:
o Abnormal ECG (LVH, L-BBB, St-T abnormalities)
o Rhythm other than sinus


Diagnosis of Arrhythmias
Pulse
Physical exam
Electrocardiogram
Stress test
Echocardiogram
Holter monitor
Event recorder
Arrhythmias
* Signs
* Symptoms

Medical Management of Arrhythmias
Antiarrhythmic Drugs
Potential Drug Concerns
Implanted Pacemaker
Placement/Functioning of Pacemaker
Implanted Defibrillator
Pacemakers/Defibrillators
Cardioversion
Surgical Ablation
Dental Management Considerations for Patients With Arrhythmias

* ID patients with significant arrhythmias; must rely on medical history; obtain medical consult if any question
* Consult with physician if patient is symptomatic (frequent palpitations, chest pain, dizziness, shortness of breath)
* Avoid elective care in patients with significant arrhythmias or with uncontrolled or poorly controlled arrhythmias
* Avoid epinephrine in uncontrolled or poorly controlled patients and in patients taking digitalis
* Avoid lidocaine in patients taking amiodarone
* With stable (controlled) arrhythmia, may use vasoconstrictor in modest amounts if needed; treat as normal patient
* Implement stress management protocol as needed
* Be mindful of anticoagulant therapy; most treatment permissible if INR is within the therapeutic range)
* Watch for digitalis toxicity (increased salivation)
* Avoid electrical interference with pacemaker

Dental Management of Patients with Cardiac Arrhythmias.ppt