Cardiac Rhythm Disturbances - Johnston Flashcards
Sinus arrhythmia
Rate changes based on respiration
Wandering pacemaker
Multiple atrial foci, different P wave morphologies
Atrial escape beat
Pause of unhealthy SA node –> ectopic focus fires (different shape P wave)
Junctional escape beat
Pause of unhealthy SA node –> ectopic AV junction focus fires (giant QRS, no P wave)
Atrial escape rhythm
Sinus arrest –> 60-80 beats/min, different P wave morphology than normal
Junctional escape rhythm
Sinus arrest –> 40-60 beats/min, no P waves or inverted P waves AFTER QRS
Ventricular escape rhythm
Sinus arrest –> 20-40 beats/min, no P waves
A ventricular pacemaker focus may ultimately cause what phenomenon?
Stokes-Adams syndrome (transient syncope via insufficient cerebral perfusion)
Premature atrial beat
Treatment?
EARLY, unique P wave –> normal, aberrant, or no QRS (depends on how early)
- IF symptomatic – Beta blocker (Metoprolol)
How does the heart respond to a single premature atrial beat?
The SA node is depolarized, then starts again at the same rate as before (RE-SETS)
Explain possible QRS’s after a premature atrial beat (3)
- TOO early = refractory ventricles = no QRS
- EARLY = 1 bundle branch refractory = ABERRANT QRS
- OK = normal QRS
Ventricular beats appearing in groups of 2 or 3, with the last one early and a different P wave
Atrial Bigeminy or Trigeminy (ectopic focus tied to SA rhythm somehow)
EKG sign of significant myocardial hypoxia/ischemia
Premature/Ectopic ventricular beats
Premature ventricular contraction
Treatment?
WIDE QRS w/o a P wave, inverted T wave, pause afterward
IF symptomatic…Metoprolol (Amiodarone/Lidocaine if really unstable)
Why is an ectopic ventricular QRS wider than a normal one?
Conduction in myocardium is slower than in the conduction system
What to avoid administering w/ ectopic ventricular beats/rhythms?
SNS stimulants or K+ wasting drugs
Ventricular beats appearing in groups of 2 or 3, with the last one wide, early, and without a P wave
Ventricular Bigeminy or Trigeminy
Ventricular Parasystole
Dual QRS rhythms at once via 2 independent pacemakers (SA and ectopic)
PVC falling immediately after a normal QRS (where T wave would be)
Significance?
“R on T” - HIGH RISK for ventricular tachy-arrhythmia
Multiple different QRSs of different morphologies and varying rates
Risk?
Multifocal PVCs
RISK of V. FIB.
Barlow Syndrome
Multifocal PVCs caused by MITRAL VALVE PROLAPSE
Tachycardia, rate 150-250, same PQRS every time
Treatment?
Paroxysmal Atrial Tachycardia (PAT) - ectopic focus overrides SA node
- Magnesium sulfate + CCB (Verapamil), then Amiodarone/Adenosine instead of Magnesium
Tachycardia (150-250), 2 P’s for every 1 QRS
PAT w/ AV Block - DIGITALIS TOXICITY + HYPO-K+
Tachycardia (150-250), inverted Ps (or none), normal QRSs
Paroxysmal Junctional Tachycardia (PJT) - ectopic focus overrides SA node
Tachycardia (150-250), no Ps, abnormal QRSs
Ventricular tachycardia
What can often be seen occasionally w/ V. tach?
Capture (normal QRS btwn VT) or Fusion beats (1/2 and 1/2)
What is Supraventricular Tachycardia?
Treatment?
Any tachycardia arrhythmia (not normal) that originates above the ventricular tissue (PAT or PJT or AVNRT)
– Tx = Adenosine
When suspecting VT, what MUST you rule out?
SVT + BBB/aberrant conduction –> wide QRS’s like VT
- NOT TREATED THE SAME AS VT
How to distinguish VT from Wide QRS SVT?
Wide SVT = no RAD or coronary disease
VT = coronary disease, captures and fusions, EXTREME RAD
Cause of Torsades de Pointes
- Low K+, K+ blockers, and/or long QT (syndrome or drug)
Good Dx tool for atrial flutter
Best leads to see it?
Vagal Maneuver (help slow AV node to show more flutter waves)
2, 3, AVF
Ventricular flutter
Smooth, sine-wave appearance (as opposed to wide QRSs), same size every time
Problem with V. flutter if not treated
PROGRESS to V. FIB due to coronary blood insufficiency
Flutter rate
250-350 beats/min
Fibrillation appearance
Random, super-fast, jagged beats w/ changing amplitudes and no recognizable pattern
What will be seen on long-term EKG w/ untreated V. FIB?
Diminished amplitude over time as heart dies
Immediate treatment for V. FIB
Defibrillation + CPR
Upward-curving R waves (“delta waves”)
Wolff-Parkinson-White Syndrome (via Bundle of Kent)
V1-V3…RBBB (RSR’) w/ ST elevation
Treatment?
Brugada Syndrome (congenital)
ICD placement
T wave inversion in V2 and V3 (upward)
Cause? Treatment
Wellens Syndrome (congenital)
LAD stenosis (stent or bypass)
QT interval greater than 1/2 the length of the cycle
Long QT syndrome (congenital)
COPD - EKG findings
- Low voltage
- RAD
- MAT (multiple p wave morphologies, abnormal rates)
Pulmonary embolus - EKG findings
S1 Q3 T3 - Large S in lead 1 - Large Q in lead 3 - Inverted T in lead 3 RAD ST depression in lead 2 T wave inversion in leads V1 - V4
Flatter, wider P wave
Wide QRS
Peaked T waves
Hyperkalemia
Flat or inverted T waves U waves (if severe)
Hypokalemia
Hypercalcemia
Short QT
Hypocalcemia
Long QT
Sinus tachycardia
Causes?
Treatment?
Elevated HR, normal PQRST
- Emotion, anxiety, fear, drugs, hyperthyroid, pregnancy, anemia, CHF, hypovolemia
- Treat underlying cause
Sinus bradycardia
Slow HR, normal PQRST (
Tachycardia, followed by bradycardia (cycle)
Sick Sinus Syndrome
When to treat sinus bradycardia?
How to treat? (preferred)
HR
SVT vs. VT
SVT - normal narrow QRSs
VT - wide QRSs
