Wolff-Parkinson White (Pre-Excitation Syndrome)
1. Shortened PR-interval
2. Delta-waves
Through Bundle of Kent
WPW Example:
Lown-Ganong-Levine (Pre-Excitation Syndrome)
1. Shortened PR-interval
2. No delta wave
3. Narrow QRS
Through James Fiber
WPW and SVT:
1. Presents as narrow complex SVT; or
2. Wide and bizarre SVT that resembles V-tach
AVRT forms through the Bundle of Kent
WPW and Atrial Fibrillation
1. Presents as rapid A-fib
2. Can induce V-fib
3. Rare
Bundle of Kent acts as a conduit for chaotic activity
Atrial Pacemaker
Pacer spikes fire BEFORE p-waves
Ventricular Pacemaker
Right ventricle contracts before the left
Dual Chamber Pacemaker
Features 2 different chamber spikes
Lateral Ischemia
ST depressions in the lateral leads
Progression of a STEMI
1. Immediate: T-wave peaking
2. Immediate: T-wave inversion
3. 0-24 hrs: ST elevation
4. Hrs-days: patholgic Q-wave; T-wave inversion
Q-wave will remain; but T-wave will eventually normalize
Ischemia vs repolarization
1. Ischemic T-waves are symmetrical
2. Repolarization is downsloping
T-wave changes during a STEMI
1. Reflects myocardial ischemia
2. Inversion is symmetrical
STEMI vs J-point
J-point goes down before coming back up
Reciprocal changes
A lead distant from an infarct records an ST depression
Hyperkalemia
Peaked, tented T-waves; loss of P-waves
Progression of hyperkalemia
Can degrade to V-fib
Advanced hyperkalemia with sine waves
Early stages of V-tach
Hypokalemia
1. Flattened T-waves
2. U-waves (sometimes)
Another example of hypokalemia
Flattened T-waves in every lead
Hypocalcemia
1. T-wave flattening
2. Prolonged QT-interval
3. Shortened PR-interval
Increased risk of Torsades
Hypercalcemia
1. Shortened QT-interval
Don't confuse with STEMI
Hypothermia
1. Sinus bradycardia
2. Prolonged segments and intervals
3. Distinct ST elevation (J wave; Osborne wave)
Digitalis effect
1. ST depression with gradual downslope (Dali)
2. T-wave flattening or inversion
Paroxysmal Atrial Tachycardia (PAT)
1. Can not distinguish from other SVTs
2. Normal or caused by digitalis toxicity
Acute Pericarditis
Diffuse ST-elevations, T-wave changes, and PR-depressions in multiple leads
Pericardial Effusion
Low voltage waveforms
Electrical Alternans
1. Heart rotates freely within fluid filled sac
2. Waveform amplitude varies from beat to beat
Severe pericardial effusion
COPD
1. Low voltage
2. Right axis deviation
3. Poor R-wave progression
4. Right atial enlargement
Acute PE
1. Right ventricular hypertrophy
2. S1Q3T3
3. Tachycardia
4. RBBB
Brugada Syndrome
1. RBBB
2. ST-elevation in V1, V2, V3
Can degrade to V-tach