Clinical arrhythmia lecture Flashcards
Some antiarrhythmics (Class 1A, 1C, Class III), erythromycin, antifungals, tricyclic antidepressants
…can cause?
Prolonged QT interval
Atrial fibrillation with controlled or slow rate in absence of meds that slow AV conduction.
Sick sinus syndrome variation
Brady-Tachy Syndrome- paroxysmal atrial tachyarrhythmias accompanied by sinus node dysfunction and symptomatic bradycardia.
Sick sinus syndrome variation
Presence of symptoms clearly related to sinus node dysfunction (pauses) proven by ECG.
40% will have concomitant AV Node dysfunction, heart block.
Sick sinus syndrome
Most common cause of sick sinus syndrome?
AGING
Sinus node dysfunction
AV node dysfunction
…treatment
permanent pacemaker
Sick sinus syndrome tx
step 1…eliminate offending drug (if applicable)
step 2..pacemaker
PAC precipitating factors
ETOH
caffeine
adrenergic stimulation
*Paroxysmal and persistent forms.**
May be seen in healthy individuals (5%) without HD
*can be precipitated by emotional stress, use of stimulants, following surgery, or with acute ETOH intoxication (“holiday heart”).
*Also occurs in absence of a precipitant
A fib
95% of A fib cases seen in the presence of…
underlying cardiac or pulmonary pathology
_____ most often seen in valvular, hypertensive and coronary heart disease
*frequently develops in adults with atrial septal defects
A fib
Irregularly irregular rhythm
atrial depol 400-600/min
*if new/untreated…ventricular rate tachycardia (often 120-180)
A fib
If rate continuously exceeds 200 bp, consider A fib with…
WPW
First priority when assessing A fib patient….
ASSESS HEMODYNAMIC STABILITY
most yes. if no…cardioversion
Must worry about thromboembolic if in A fib for longer than….
48-72 hours
Diagnostic test that all new onset A fib patients must have
Cardiac ultrasound (echo)
If hemodynamically stable, initial goal for a fib tx
Rate control
IV _____ is best for rapid rate control in ED for A fib
Diltiazem
Oral diltiazem, verapamil, or beta blockers
Best for chronic rate control of A fib
If A fib present for longer than 72 hours…
MUST FULLY ANTICOAGULANT
no cardioversion until 3 weeks of anti coagulation
2 chronic A fib management strategies
- rhythm control
2. rate control
cardioversion to NSR+ drug Rx to maintain sinus rhythm→↑ CO/function, but side effects of meds, recurrences of Afib.
Rhythm control strategy of A fib
leave in afib, control ventricular rate + anticoagulate (warfarin* for most patients)
Rate control strategy of A fib
CHADS2 or CHADS VAS
used to calculate risk of stroke
If a pt with a fib has a CHADS score of 0…
Can leave in a fib, don’t need to anticoagulate
Definitive treatment for A fib rhythm control…
Ablation with surgery or catheter
65-90% success
This drug class appears to increase risk of developing a fib or a flutter
NSAIDs
Underlying heart disease always present.
**Paroxysmal and persistent forms.
Embolization risk less than Afib but occurs.
*Rate usually 240-350; ventricular rate most often 1/2 the flutter rate; less stable hemodynamically; difficult to slow with meds.
A flutter
Most effective tx for A flutter
DC cardioversion
often need meds to prevent recurrence
If you see a 4:1 atrial flutter..is this person already being treated?
Most likely yes
Re-entry is responsible for vast majority of cases
Seen in any age group, especially healthy young adults.
***Narrow complex, regular tachycardia, rate usually 150-220.
**P waves usually not identifiable; may come after QRS
PSVT
2 pathways of AV node
Alpha and beta
Requires dual AV nodal (α & ß pathways) that can conduct in either direction.
**Initiated by PAC conducted antegrade down one (β) AV pathway; if conduction slow enough to allow previously refractory other (α) pathway time to recover, impulse will be conducted retrograde back through the AVN initiating a re-entry circuit
PSVT
DOC for PSVT
Adenosine
Interventions that increase vagal tone (e.g. carotid message or valsalva) may abruptly terminate the rhythm.
PSVT
Selective ablation of AV node can be tx for
PSVT
Accessory A-V bypass tract (Kent Bundle) allows conduction to ventricles as alternative to the AV node.
ECG findings: Short PR interval and Delta waves
WPW
Can you use Adenosine, ß-Blockers, Diltiazem, Verapamil in a WPW pt with A fib or A flutter?
NO!!!!
can use Procainamide or Amiodarone
Lidocaine will slow conduction through…
kent bundle! (in WPW)
Radio Frequency Ablation: Catheter ablation of the bypass tract is effective (90%) and curative. Treatment of choice for most ____ patients.
WPW
Most patients developing VF within 1st 48 hrs of an acute MI have a _____ prognosis if successfully resuscitated
good long term
Resuscitated VF unassociated with acute MI has a very high recurrence rate (> 30% recur within the first year following the initial event), and carries a….
very poor prognosis
*tx with ICD
most common cause of sudden cardiac death
V fib
V fib sometimes occurs following administration of antiarrhythmic drugs - especially in patients with….
prolonged QT interval
prominent jugular pulsation and palpable parasternal lift
- harsh systolic murmur best heard at second and third left intercostal space
- radiates to left shoulder
- early systolic sound precedes the murmur during expiration
Pulmonic stenosis
