Clinical Aspects Of Cardiac Arrhythmias Flashcards
Rate of less than 60 bpm w/ each P wave followed by a QRS and each QRS preceded by a P wave
Sinus Bradycardia
Sudden cessation of sinus node activity as evidenced by loss of atrial depolarization
Sinus arrest
What do we call a sudden cessation of sinus node activity if it is for
- ) Less than 3 seconds
- ) More than 3 seconds
Sinus Arrest
Resting sinus bradycardia with periods of supraventricular tachycardia often followed by sinus pauses or sinus rest
Brady-Tach syndrome
Diagnosed by a rate less than 60 bpm, w/ sinus pause or sinus arrest
Sick sinus syndrome
We can treat sick sinus syndrome w/
Atropine (anti-cholinergic), Beta agonists, and temporary pacemaker
Impaired conduction between the atria and ventricles
AV block
What are the three types of AV block?
- ) First degree
- ) Second degree
- ) Third degree
Characterized by a PR interval of greater than 0.2 sec w/ 1:1 relationship between P waves and QRS
First degree AV block
A 1st degree AV block can be caused by an
Inferior MI
There is usually no treatment see for a
-Avoid drugs that will cause further impairment
First degree AV block
Intermittent failure of AV conduction w/ some P waves not followed by QRS complex but constant P to P intervals and prolongation of PR interval before block
Mobitz type I 2nd degree AV block (Wenckebach)
An inferior MI, Lyme myocarditis, an congenital AV block can all cause
Wenckebach Block
For a mobitz I (Wenckebach) block, we may need to treat w/
Atropine or isoproterenol
Intermittent failure of AV conduction w/ some p waves not followed by QRS complex, constant P to P intervals and NO prolongation of PR interval before block
-QRS is usually wide
Mobitz Type II second degree AV block
An intermittent conduction block distal to the AV node in the bundle of His
Mobitz Type II
Clinically presents w/ syncope (Stokes-Adams), dizziness, extensive anterior MI
Mobitz Type II second degree AV block
Complete failure of conduction between atria and ventricle w/ NO relationship between p waves and QRS
-Sinus rate is greater than ventricular rate
3rd Degree Heart Block
Treated w/ a permanent pacemaker unless their is reversible AV nodal injury
3rd degree heart block
Normal, narrow QRS complexes at rates of 40-60 bpm w/ no p wave preceding the QRS
-May have retrograde p waves
Junctional Escape Rhythm (JESC)
Diagnosed by wide QRS complexes at rates of 30-40 bpm w/ no p wave preceding the QRS
-May have retrograde p waves
Ventricular Escape Rhythms (VESC)
Increased automaticity of the SA node by way of either increased sympathetic tone or decreased parasympathetic tone
Sinus Tachycardia
Premature p wave, usually followed by normal narrow QRS but can also be followed by wide (aberrantly conducted) or by no QRS
Atrial premature complexes
Can be caused by increased sympathetic tone, stretch, and fibrosis
Atrial Premature Complexes
Atrial Premature Complexes (APCs) are usually followed by normally conducted
Narrow QRS complexes
When the APC are very premature and fail to conduct to the ventricles or conduct w/ an aberrantly conducted complex due to block in the right or left bundle
APC w/ aberrancy and blocked APC
Rate greater than 100 bpm w/ p wave morphology that is different than typical sinus p wave morphology
-sudden onset and termination
Atrial Tachycardia
Can be the result of abnormal automaticity, DAD, or reentry
Atrial Tachycardia
Treated w/ beta blockers, Ca2+ blockers, class IC or III antiarrhythmic drugs, or ablation
Atrial Tachycardia
Rapid, regular, uniform atrial activity at a rate of 240-300 bpm
-Inferior leads have “Saw-tooth” appearance
Atrial Flutter
Caused by reentry along the tricuspid valve annulus
Atrial Flutter
An atrial flutter will often present w/ a
2 to 1 Block
Irregularly irregular rate w/ no discernible p waves on the ECG but w/ low amplitude oscillations
-Presenting ventricular rate is usually 140-160 bpm
Atrial Fibrillation
Multiple wandering atrial reentrant circuits w/ atrial rate
-Pulmonary vein triggers may initiate
Atrial Fibrillation
Associated w/ hypertension, cardiomyopathy, CHF, mitral stenosis, mitral regurgitation, and ischemic heart disease
Atrial Fibrillation
Acutely, we want to treat atrial fibrillation w/
Beta-blockers and Calcium-blockers
For chronic treatment of atrial fibrillation, we want to give meds for which 3 purposes?
- ) Anticoagulation
- ) Rhythm control
- ) Rate control
The sudden onset and termination of heart rates between
140and 250 bpm
Regular, rapid, usually narrow QRS complex rhythm at rated of 140-250 bpm
AV nodal reentrant tachycardia
Acutely, we can treat AV nodal reentrant tachycardia w/
Vagal maneuvers and adenosine
Characterized by a short PR interval (less than 0.12 sec) w/ normal sinus p waves, wide QRS, and a delta wave that slurs first portion of QRS
Ventricular Pre-excitation (Wolff-Parkinson-White Syndrome WPW)
Rapid conduction across the bypass tract and down the AV node w/ varying degrees of fusion
Atrial fibrillation in WPW
Premature QRS complex, which is wide, because the impulse travels from its ectopic site through the ventricles via slow cell-to-cell connections
Ventricular Premature Complexes
W/ a ventricular Premature Complex, the ectopic complex is not related to a
Preceding P wave
Defined as more than 3 consecutive PVC at greater than 100 bpm
Ventricular tachycardia
Rapid, wide QRS complex rhythm at rats of 100 to 300 bpm w/ all QRS complexes having the same morphology
Sustained Ventricular Tachycardia
Consecutive wide QRS complexes w/ continually changing shape and rate from complex to complex
Polymorphic Ventricular Tachycardia
ECG shows irregular deflections of varying amplitude and contour w/ no defined P waves, QRS complexed, or T wavs can be recognized
Ventricular Fibrillation
Characterized by multiple reentrant circuits and clinically presents as cardiac arrest
Ventricular Fibrillation
The cause of congenital long QT syndrome is an
Ion Channel Mutation
Characterized by a coved type ST elevation
Brugada syndrome
Characterized by a saddle-back type ST elevation
Brugada Syndrome
Characterized by a very mild saddle-back “ST elevation”
Type 3 Brugada Syndrome
A genetic arrhythmogenic disorder characterized by a peculiar ECG pattern
Brugada Syndrome
Predisposes to ventricular arrhythmias and sudden cardiac death
-Affects males much more than females
Brugada Syndrome
Caused by a mutation in genes coding for Calcium handling by proteins
Familial catecholaminergic polymorphic ventricular tachycardia
Long QT 1 is triggered by
Exercise (swimming)
Long QT 2 is triggered by
Auditory stimuli
Long QT 3 often occurs at
Rest
