12 Lead EKGs Flashcards
Class I anti arrhythmic drugs
Na channel blockers
- 1a: Qiudinine, procainamide, disopyramide (prolong QT, prolong QTc)
- 1b: Lidocaine, phenytoin, mexiletine (minimal to no EKG changes)
- 1c: Flecainide, propafenone (widened QRS, prolong PRI, sinus node suppression)
Class II anti arrhythmic drugs
Beta blockers
- Metoprolol, carvedilol
- Decrease sinus rate, prolong PR, *may contribute to heart block
Class III anti arrhythmic drugs
K channel blockers (depolarization)
- Sotalol, dofetilide, dronedarone (prolonged QT)
- Amiodarone (prolonged QTI)
Class IV anti arrhythmic drugs
Ca channel blockers
- Verapamil, diltiazem
- Decrease sinus rate, prolonged PR, *may contribute to heart block
Other anti arrhythmic drugs
Digoxin, adenosine
What does a negative/inverted T wave indicate?
Ischemia or evolving MI
What part of the T wave is the heart most susceptible to arrhythmias caused by PVCs?
Second part
Normal QTC
Less than .46
Left ventricular hypertrophy
- Thickening of myocardium
- Often left axis deviation, wide QRS, LBBB
Most common cause of LVH?
HTN
Variation of LVH
Hypertrophic cardiomyopathy
- May cause sudden death
Pericarditis findings
- Diffuse ST elevation
- PR depression
Pericarditis sx
- Pleuritic chest pain, relieved by sitting forward
- May have preceding viral syndrome, fever common
- May have pericardial rub on exam
- SOB if effusion is present
Pericarditis tx
- Anti-inflammatories
- Tx of underlying cause
- Drain any effusion present
Pericardial effusion
- Can cause global low voltage or electrical alternans
- Can lead to pericardial tamponade
Hyperkalemia
- Peaked T waves
- As K increases, conduction system slows (in atria 1st, then ventricles) –> loss of p waves –> new bundle branch block –> bradycardia –> asystole, PEA or VF
Hypokalemia findings
- Prolonged QTI
- ST depression
- T wave inversion
- Sometimes large U waves
WPW EKG findings
- Short PR interval
- Delta wave
- Widened QRS
WPW
Direct connection to ventricle though bundle of Kent
WPW tx
If pt has sx, ablation of accessory pathway is necessary
What are pulmonary embolisms caused by?
An embolus from the deep venous circulation
Risk factors for DVT
Virchow’s triad:
- Venous stasis
- Injury to the vessel wall
- Hypercoagulability
Sx of pulmonary embolism
- Dyspnea
- Tachycardia
- Tachypnea
- Pleuritic chest pain
- Sx can be vague
Dx of pulmonary embolism
CT scan w/ contrast
Tx of pulmonary embolism
Anticoagulation, thrombolytic therapy
Axis
- Overall direction of electrical conduction
- Found via limb leads
- Normal = -30 to 90 degrees
Left axis deviation
-30 to -90 degrees
Right axis deviation
90 to 180 degrees
What does an abnormal axis suggest?
Change in shape/orientation of heart OR defect in conduction system
Right atrial enlargement findings on EKG
- Peaked P wave, V1 or inferior leads (greater than 1.5mm in V1, greater than 2.5mm on II)
Most common cause of right atrial enlargement?
Pulmonary HTN
Left atrial enlargement findings on EKG
- Wide terminal negative portion of the P in V1 (at least 1 small box)
- Notched wide P in inferior leads, esp. lead II (at least 3 small boxes)
Biatrial enlargement
- Peaked & broad Ps in inferior leads (2.5mm tall & 1.2 seconds wide)
- V1 broad & biphasic, w/ terminal negative deflection at least 1mm deep & .04 seconds wide
Bundle Branch Blocks
- May be complete or incomplete through one of the bundles
- QRS of .1-.12 could mean incomplete or hemiblock
- QRS of .12 or greater is likely CBBB (if it does not fit the pattern for RBBB or LBBB, then it is an inter ventricular conduction delay)
LBBB
- V1 will be negative, w/ big Q wave or rS complex
- V6 will be positive
- May also have left axis deviation
What is LBBB associated with?
Underlying cardiac disease
RBBB
- V1 will be upright & V1-2 will have “bunny ears” appearance
- First R wave = LV activation, 2nd R wave is RV activation
Lateral leads
I & avL
Inferior leads
II, III, & avF
Anterior leads
V1, V2, V3, V4
Anterio-lateral leads
V5 & V6
Sx of STEMIs
- Chest pain (may be vague or absent)
- SOB
- Diaphoresis
- Left arm or jaw discomfort
- Back pain btw shoulder blades
STEMIs are a result of what?
An occlusive coronary thrombus at site of preexisting atherosclerotic plaque
STEMIs tx
- ASA/plavix
- Immediate angiography & percutaneous intervention (including stent if needed)
- If angiography not available, then thrombolytics are next best option
- Morphine, beta blockers, nitrates
