Part 15 Flashcards
AV nodal re-entry tachycardia treatment (3)
- mammalian diving reflex, vagal maneuvers of carotid, valsalva
- adenosine 6mg rapid IV bolus (stops heart with a chemically short half life drug to allow for full refractory period to return)
- Electrophysiologist (EP) lab referral***
Mammalian diving reflex
When water fills the nostrils, the autonomic nervous system redirects blood flow thru peripheral vasoconstriction from the limbs and viscera to the heart and brain to conserve oxygen, causes slowing of the heart rate
AV reentrant tachycardia (AVRT) nick name
Wolf parkinson white syndrome
Atrial flutter
Involves circus movement (conduction around same loop in atrium) generally 250-350 bpm, saw tooth pattern, often with picket fence P waves seen in leads 2, 3, and AVF
atrial flutter treatment (4)
- Digoxin
- B blockers or Ca2+ blockers
- pacemaker
- ablation
Atrial fibrillation
Occurs when atrial rate is 350-700 bpm, ventricular rate may be normal or rapid, involves a complete lack of P waves, irregularly irregular rhythm, at risk for stroke and hypotension
Common causes of atrial fib (4)
- thyroid abnormalities
- alcohol
- COPD
- underlying heart disease
Afib treatment (3)
- rate control (B blockers, Ca2+ channel blockers, digoxin
- anticoagulation before and after cardioversion
- rhythm control
Defibrillation will not work on a heart that has reached what stage of arrest?
Asystole
Ventricular arrhythmias occur from the…
….AV node down
ventricular tachycardia
3 or more successive PVC’s, nonsustained is less than 30 sec and sustained is more, rate >100bpm usually regular rhythm, may or may not see P waves
Torsades de pointes
Form of polymorphic ventricular tachycardia assoc with prolonged QT interval >500ms, changes in amplitude and morehphology of QRS around isoelectric line, causes of prolonged QT interval can be congenital or acquired
Ventricular fib requires…
…electric shock
Brugada syndrome
Congenital channelopathy caused by mutation of cardiac Na+, K+ or Ca2+ , ST segment elevation in one of the right precordial leads (V1-V3) at baseline or after use of Na+ blockers, 3 subtypes
Commotio cordis
Ventricular fib caused by blunt, non-penetrating blow to chest during vulnerable portion of ventricular repolarization, more common in children and adolescents, more common with moderate to high velocity strike usually projectile right during a T wave
Ventricular flutter
Ventricular tachyarrhythmia 250-350 bpm, rapidly deteriorates into ventricular fib
Ischemia will manifest on an EKG as…
…ST depression
ST elevation indicates…
Acute injury within past 24-48 hrs
T wave inversion or ST elevation or depression across all leads is pathonomonic of what condition?
Pericarditis
Punumbra
Direct death of tissue from blocked artery that is not perfused, surrounded by ischemic and injured tissue in a circular area around the source
Lesions that occlude LAD represent ___% of MI’s, RCA represents ___%, and circumflex represents ___%
50, 30, 20
Inferior wall MI is represented in leads…
II, III, and AVF
Lateral wall MI is represented in leads…
I, AVL, V5, V6
Septal/anterior wall MI is represented in leads…
Septum: V1,2,
Anterior: V3,4