Rhythm Flashcards
Mechanism and impulse initiation of torsades de pointes
Triggered automaticity
EADS
Mechanism and impulse initiation of digitalis toxicity and reperfusion Vtach
Triggered automaticity
DADs
Mechanism and impulse initiation of sinus bradycardia and sinus tachycardia
Mechanism: automaticity
Impulse initiation: suppression or acceleration of phase 4
Mechanism and impulse initiation of ischemic ventricular fibrillation and AV block
Excitation
Suppression of phase 0
AP SHORTENING
INEXCITABILITY
Mechanism and impulse initiation of polymorphic VT
AP PROLONGATION , AED, DADs
REPOLARIZATION
Mechanism and impulse initiation of AF FIBRILLATION
AP SHORTENING
REPOLARIZATION
Mechanism and impulse initiation of ischemic VT/ VF
Decreased coupling
Cellular coupling
Mechanism and impulse initiation of monomorphic VT, AF
EXcitable gap and function RE-ENTRY
TISSUE STRUCTURE
Renders heart inexcitable by depolarizing the membrane potential
Hyperkalemia
Due to presence of increased Calcium load In the cytosol and sarcoplasmic reticulum
Delayed after depolarization
Causes of DADs
Digitalis glycosides
Catecholamines
Ischemia
Causes of EADS
Hypokalemia
Hypomagnesemia
Bradycardia
Drugs( class IA and Class III, phenothiazines, nonsedating antihistamines, some antibiotics)
Most common arrhythmia mechanism
RE-ENTRY
What type of Re-Entry arrhythmia has no fixed an atomic obstacle, and no fully excitable gap.
Ex AF VF
Leading circle Re-Entry
What type of Re-Entry arrhythmia has fixed anatomic structure with anterograde and retrograde limbs of the circuit
Ex
AV RE-ENTRY, ATRIAL FLUTTER, BUNDLE BRANCH REENTRY VENTRICULAR TACHYCARDIA AND VENTRICULAR TACHYCARDIA IN SCARRED MYOCARDIUM
Excitable gap Re-Entry
Or
anatomic reentry
Test used to evaluate patients with syncope when suspecting exaggerated vagal tone or vasodepression as a cause
HEAD UP TILT TESTING
HUT
Mechanism of bradyarrhythmia
Failure of impulse initiation
Or
Impulse conduction
Most common causes of pathological bradycardia
Sinus node dysfunction
AV conduction block
Only reliable therapy of bradyarrhythmia if without reversible causes
Permanent pacemaker inertion
The incidence of persistent atrial fibrillation in patientswith SA node dysfunction increases with
advanced age, hypertension, diabetesmellitus, left ventricular dilation, valvular heart disease, and ventricular pacing.
Patients with the tachycardia-bradycardia variant of SSS,similar to patients with atrial fibrillation are at risk for thromboembolism, and those at greatest risk who should be treated with anticoagulants are:
aged ≥65 years
patients with a prior history of stroke,
valvular heart disease,
left ventricular dysfunction, or atrial enlargement,
The electrocardiographic manifestations of SA node dysfunctioninclude
sinus bradycardia, sinus pauses, sinus arrest, sinus exit block,tachycardia (in SSS), and chronotropic incompetence
Sinus bradycardia is ABNORMAL if
HR<40bpm in the awake state in the absence of physical conditioning
This is alternatively defined as failure to-reach 85% of predicted maximal heart rate at peak exercise or failure to achieve a heart rate >100 beats/min with exercise or a maximal heartrate with exercise less than two standard deviations below that of an age-matched control population. Exercise testing may be useful in discriminating chronotropic incompetence from resting bradycardia
Failure to increase the heart rate with exercise is referred to as chronotropic incompetence.
The normal IHR after administration of 0.2 mg/kg propranolol and 0.04 mg/kg atropine is ____; a low IHR is indicative of SA disease.
is 117.2 − (0.53 × age) in beats/min
Drugs that may be used In AV BLOCK
Atropine 0.5 to 2 mg IV
OR
ISOPROTERENOL 1-4 ung/min IV
Transient abnormality associated with Mobitz type 1 second degree av block:
Inferior wall MI
DRUGS (digitalis, CCB, BB)
Increased vagal tone
Associated with PAROXYSMAL AV BLOCK
Mobitz Type 2 sec degree AV block
Typical site of block for Mobitz Type 2 sec degree AV block
Infranodal
Distal or infra-his conduction system
The most common arrhythmia identified during extended ECG monitoring
Atrial premature complexes
The SIGNITURE tachycardia of patients with significant pulmonary disease
MAT
Multifocal atrial tachycardia
Lupus erythematosus like syndrome is commonly seen in slow acetylators of this anti-arrhythmic Agent
PROCAINAMIDE
Most common sustained arrhythmia
AF
Approach if AF if adequate rate control is not achieved:
Consider restoring to sinus rhythm by CATHETER ABLATION OF AV JUNCTION + placement of PACEMAKER
If AF is unclear of <48hours
Anticoagulate before cardio version
Underlying condition in AF that necessitates anticoagulantion:
Mitral stenosis
Hypertrophic CMP
prior history of stroke
CHADSVAS SCORE OF >/= 2 (May consider 1)
Anticoagulant choice for rheumatic MS or mechanical heart valves in AF
Warfarin (Vitamin k antagonist)
Anticoagulant choice for non-valvular AF
Warfarin and direct acting anticoagulants
ANTITHROMBIN INHIBITORS
choice for non-valvular AF
Dabigatran
Factor Xa inhibitors used in non-valvular AF
Rivaroxaban
APIXABAN
Endoxaban
Avoid dabigatran, rivaroxaban and APIXABAN crea clearance is below
<15cc/min
If modest renal impairment just adjust to renal dose
True or false:
In AF, IF RECURRENCES ARE INFREQUENT, MAY DO PERIODIC CARDIOVERSION.
True
Pharmacotherapy to maintain sinus rhythm or reduce episodes of AF if without significant structural heart disease:
Class IC Sodium channel blocking agents
Flecainide
Propaferone
Disopyramide
Pharmacotherapy to maintain sinus rhythm or reduce episodes of AF if with CAD or structural disease:
Class III agents
SOTALOL
DOFETILIDE
More effective drug compared to others as Pharmacotherapy to maintain sinus rhythm or reduce episodes of AF if with CAD or structural disease:
AMIODARONE CLASS III
Slightly SUPERIOR compared to DRUG THERAPY for UNTREATED RECURRENT PAROXYSMAL AF
Catheter ablation directed at pulmonic veins foci (less effective fir persistent AF)
More effective for PERSISTENT AF than catheter ablation
SURGICAL ABLATION
Have wide QRS complexes > 0.12secs
Capable of automaticity, triggered automaticity, reentry thru areas of scar or diseased purkinje system
Ventricular arrhythmias
Single ventricular beat that falls earlier than the next anticipated supraventricular beat
PVCs
> 3 consecutive beats at >100bpm
Vtach
Distinguishing time between non sustained Vtach and sustained Vtach
30 seconds
Waxing and waning QRS complex
Torsades de pointes
PVCs or VTACH in patients without structural heart disease and not associated with genetic syndrome or sudden death
Idiopathic ventricular arrhythmia
Anti arrhythmic drug for EIA, IDIOPATHIC ARRHYTHMIA
First choice for most ventricular arrhythmia due to safety
Beta blocker
Block the delayed rectified potassium channel IKR which:
prolongs action potential duration (QT INTERVAL) and cardiac refractory period
Predisposes to TORSADES DE POINTES
SOTALOL , DOFETILIDE
K CHANNEL BLOCKERS
Most effective anti arrhythmic for ventricular arrhythmia, better than SOTALOL for reducing ICD shocks
AMIODARONE
Major adverse effects of AMIODARONE Which
Leads to discontinuation in 1/3 of patients
Hyper or Hypothyroidism Pneumonitis or pulmonary fibrosis (PULMONARY INFLAMMATION) Photosensitivity Peripheral neuropathy Ocular toxicity Hepatoxicity
Major adverse effects of AMIODARONE if given by IV administration for >24 hours via a peripheral vein
SEVERE PERIPHERAL THROMBOPHLEBITIS
Highly effective for terminating VT AND VF, decreases mortality of sudden cardiac death
ICD
implantable cardioverter defibrillators
Indications for catheter ablation For VT
- Recurrent (incessant) ventricular arrhythmias associated with poor cardiac function
- Idiopathic VTach and PVCs without structural heart disease
Anti-arrhythmic surgery used for recurrent VT DUE to prior MI, some cases of VT in non-ischemic heart diseaSe
Surgical cryoablation +/- aneurysmectomy
Most common origin of idiopathic ventricular arrhythmia
RV OUTFLOW TRACT (LBBB configuration)
Structural heart origin in LBBB like configuration
RV or IV septum origin
Dominant S in v1
Structural heart origin in RBBB like configuration
LV origin (Dominang R is V1)
ECG characteristic of Vtach with inferior wall origin
Negative II III AVF
Structural heart origin with ECG: positive II II AVF
Cranial aspect of the heart origin
Indication for ICD for survivors of AMI with PVCs or non sustained Vtach (decreases mortality)
> 40 days after acute MI + LVEF <0.30 + symptomatic HF (II or III)
And
> 5days after MI + Dec LVEF + non sustained VT + inducible sustained VT or VF on electrophysiological testing
PVCs at a rate < 100 beats/min
Idioventricular rhythm
ECG CRITERIA
FOR SUSTAINED VENTRICULAR TACHYCARDIA
- Presence of AV Dissociation
- Monophasic R wave or Rs complex in AVR
- Concordance from V1 to V6 of monophasic R or S waves
- favors SVT: known BBB + same QRS morphology during tachycardia and sinus rhythm
≥3 Vtach or vfib episodes within 24hours
Electrical storm or VT storm
Management of Electrical storm or VT storm with
prolonged QT causing TDP torsades de pointes
IV MAGNESIUM SULFATE
Management of Electrical storm or VT storm with
Brugada syndrome
QUINIDINE
ISOPROTERENOL
The major source of thromboembolism and stroke in AF is formation of thrombus in the _____ where flow is relatively stagnant,although thrombus occasionally forms in other locations as well.
left atrial appendage