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1 CV, Arrhythmias
Step Up to Medicine, Chap 1: Arrhythmias
Question | Answer |
---|---|
Tx for PACs? | Asymptomatic (most): no tx. Symptomatic: beta blockers |
What kind of EKG abnormalities would you see with a PVC? | Slower rate of conduction, wide QRS w/hidden P wave (buried in QRS) |
Tx for PVCs? | Asymptomatic: none. Symptomatic: beta blockers. May need ICD if also have underlying heart disease due to increased risk of sudden cardiac death |
What is bigeminy? | Sinus beat followed by a PVC. |
What is trigeminy? | Sinus beat followed by 2 PVCs. |
Name that arrhythmia!: multiple atrial foci firing continuously in a chaotic pattern causing irregularly, rapid ventricular rate | Afib (rate=75-175) |
Why is cardioversion specifically timed NOT to hit the T wave? | Hitting the T wave can cause VFib (wan't to aim for QRS instead). Yikes! |
Which type of shock is delivered out of synchrony with QRS? Indication? | Defibrillation. Indicate: Vfib, Vtach w/out pulse |
EKG findings with Afib? | Rapid series of tiny, erratic spikes with no P waves |
Agents of choice for rate control in hemodynamically stable Afib pt? | Beta blockers and CCBs. Target rate 60-100bpm. If LV dysfunction, consider digoxin |
In which case must a pt be anticoagulated b/f undergoing cardioversion for Afib? For how long must they be anticoag'd? Goal INR? | If Afib present >48h. Anti-coag 3 weeks prior to cardioversion and 4 weeks s/p cardioversion. Goal INR 2-3. Can also do TEE first (still anticoag after). |
Which pts with chronic Afib do NOT need to be anticoag'd? | Lone Afibbers (no underlying heart disease or cardiac risk factors) or pts <60yo. EVERYONE else should be anticoag'd with warfarin. |
Name that arrhythmia!: one irritable automaticity focus in atria with sawtooth baseline on EKG with a QRS every 2nd/3rd tooth (P wave) | Atrial flutter |
Name that arrhythmia!: seen in pts with severe COPD; at least 3 different P wave morphologies on EKG | Multifocal atrial tachycardia |
Is electrical cardioversion useful in multifocal atrial tachycardia? | Nope. Manage medically (CCBs, beta blockers, dig) |
Name that arrhythmia!: Narrow QRS complexes with no discernible P waves most often due to re-entry | Paroxysmal Supraventricular Tachycardia (PSVT) |
MC arrhythmia assoc'd with dig toxicity? | Paroxysmal atrial tachycardia with 2:1 block |
Drug of choice to treat acute Paroxysmal Supraventricular Tachycardia (PSVT)? | IV adenosine (short duration of action; works by decreasing sinoatrial and AV nodal activity) |
Drug of choice for prevention of PSVT? | Dig (verapamil and beta blockers are alternatives). Can also ablate AV node or accessory path if pt has recurrent, symptomatic episodes. |
Name that arrhythmia!: accessory conduction pathway from atria to ventricles causes premature ventricular excitation b/c it lacks delay normally seen in AV node | Wolf Parkinson White Syndrome |
EKG findings for WPW? | Narrow complex tachycardia, short P-R interval, and delta wave (upward deflection seen before QRS complex). Note: delta wave isn't seen with anterograde. |
Which drug should be avoided in WPW? Why? | Dig. Acts on AV node and may accelerate conduction thru accessory path. Use IAor IC antiarrhythmics or ablate accessory path. |
Name that arrhythmia!: rapid and repetitive firing of 3+ PVCs in a row at a rate of 100-250bpm. | V tach |
Where does V tach originate? | Below bundle of His |
MCC V tach? | CAD with prior MI |
Name 5 factors that prolong the QT interval. What is this a risk factor for? | 1. Congenital QT syndromes, 2. TCAs, 3. Anticholinergics, 4. Electrolyte abnormalities, 5. Ischemia. Risk factor for torsades de pointes. |
Which physical finding on the neck might you see in V tach? | Cannon a waves (atria contract at same time as ventricles). Also get S1 that varies in intensity. |
EKG findings for V tach? | Wide, bizarre QRS complexes. |
Does V tach respond to vagal maneuvers or adenosine like PSVT? | Nope. |
Tx for sustained V tach? | Hemodynamically stable: IV amiodarone, IV procainamide, or IV sotalol. Unstable: immediate synchronous DC cardioversion; follow with IV amiodarone for rate control. ICD placement if EF abnormal. |
Tx for unsustained V tach? | If no underlying heart disease, NO increased risk of sudden cardiac death. If underlying heart disease, ICD placement. Amiodarone for pharm (2nd line tx). |
Name that arrhythmia!: multiple foci in ventricles fire rapidly leading to chaotic quivering of ventricles w/no cardiac output | VFib |
MCC VFib? | Ischemic heart disease |
EKG findings with VFib? | No identifiable P waves, no identifiable QRS. Basically no identifiable anything. Total chaos. |
Tx for VFib? | Immediate defibrillation and CPR. Medical emergency! |
Is defibrillation useful in asystole? | No. Try transcutaneous pacing instead. |
At what rate does sinus bradycardia become clinically significant? | <45bpm |
Name 3 indications for cardiac pacemakers. | 1. Symptomatic heart block (Mobitz II or complete), 2. Symptomatic bradyarrhythmias, 3. Tachyarrhythmias |
Name that arrhythmia!: prolonged PR interval, QRS after every P wave, benign | First degree AV block (delay usually in AV node) |
Name that arrhythmia!:progressive prolongation of PR interval until QRS is dropped; benign | Mobitz type II (Wenkebach); (block usually in AV node) |
Name that arrhythmia!: P wave drops without warning PR interval prolongation; sudden dropping of QRS | Mobitz type II |
Where is block in Mobitz type II? | His-Purkinje system |
Tx for Mobitz type II? | Pacemaker |
Name that arrhythmia!: absence of conduction of atrial impulses to ventricles; QRS and P waves have no relation to each other | Third degree (complete) block; characterized by AV dissociation |
Tx for complete 3rd degree block? | Pacemaker |