Atrial arrhythmias

Supra - ventricular Tachycardia (SVT)

  • Rapid rhythms originating from atria/AV node (above the ventricles)

  • Narrow complex - unless there is something messing with conduction down the normal path (bundle branches)

  • Episodic SVTs (abrupt onset & offset) = paroxysmal SVTs (PSVT)

Patho

  • Sinus origin: ↓ SV ➔ compensatory ↑ in HR (MI, HF), etOH/stimulants, hyperthyroid

  • Ectopic origin: Focus/foci fires fast enough to take control of rate

  • Reentry: electrical loop

SSX

  • Palpitations "I feel my heart pounding"/"I feel like my heart is racing", chest pain

  • ↓ diastolic filling ➔ ↓ CO ➔ ↓ perfusion ➔ Dizzy/presyncope/syncope

  • Polyuria/urgency (atria contracting with closed valves ➔ ↑ pressure ➔ ↑ ANP)

DX

  • What is the clinical picture? Gradual or sudden onset? Hx of?

  • How fast is it?

  • What does the P wave look like?

  • What is the relationship of the P and the QRS?

TX

  • Click here for tachy algorithm

  • In general: Sick or not sick?

    • Sick:👨‍🏭 (DC cardioversion). Consider adenosine if regular and narrow

    • Not sick: ACLS

Sinus Tach (Not SVT)

  • HR > 100

  • Regular

  • EKG

    • Normal P-wave and they all look the same

    • Narrow QRS


  • How fast is this? ~ Two big boxes in between

  • If regular: 300, 150, 100, 75, 60, 50

Multifocal atrial tachycardia

Multifocal: many origins in atria ➔ different looking P-waves

  • HR 100 - 180

  • Irregularly irregular

  • Patho

    • Pulmonary dz (COPD)/RAE↓ O2/ ↑ CO2 / ↑ H+, hypoK, HypoMg

  • EKG

    • > 3 different & distinct P-waves with variable PR

      • Isoelectric baseline (make sure it isn't a-flutter or a-fib)

      • A-fib has no distinct P-waves

  • TX

    • β-blockers, CCB if pulmonary DZ present

      • (β blockers bad in COPD/asthma)

Wandering atrial pacemaker: 3 different P-waves with HR < 100

Rapid AFIB

  • HR 110 - 160

  • Irregularly irregular

  • EKG

    • No discernible P-waves

  • TX

    • β-blockers, non-dihydropyrdine CCB (diltiazem), digoxin

    • DC cardioversion if sick

    • Anticoagulation

    • Ablation is definitive

    • Vagal maneuvers/adenosine usually won't cardiovert a-fib

      • Can slow rate down enough to see fibrillatory waves but can also cause ↑ ventricular response and worsening rate

A-FLUTTER

  • HR Atrial rate is 300

    • AV conduction ratio (how many impulses get through to ventricle) ➔ ventricular rate

      • 1:1 - 300

      • 2:1(MC) - 150

      • 3:1 - 100

      • 4:1 - 75

  • Regular

    • Regularly irregular if 2:1/4:1 in fixed pattern

    • Irregularly irregular if variable block

  • Patho

    • Reentry within right atrium, usually around tricuspid valve

  • EKG

    • Flutter waves (saw-tooth pattern) best seen in inferior leads

  • TX

    • β-blockers, CCB (non-dihydropyrdine)

    • DC cardioversion if sick

    • Anticoagulation

    • Ablation is definitive

    • Vagal maneuvers and adenosine will not cardiovert flutter to NS

      • But can slow the rate down enough to see flutter waves

Accelerated junctional Rhythm (AJR)/Junctional Tachycardia

  • HR 70-100 (AJR), > 100 (junctional tach)

  • Regular

  • Patho

    • AV junction puts out a higher rate than the SA node and takes over pace

    • Classic cause of AJR is digoxin toxicity

  • EKG

    • Inverted P-waves in inferior leads, absent, or buried in QRS

    • Short PR in junctional tachycardia

  • TX

    • Typically transient; IV β-blockers or CCB (non-dihydropyrdine) in acute

Atrioventricular NODAL reentry (AVNRT)

  • Functional reentry circuit (within AV node)

  • Common cause of PSVT

  • HR 150 - 220

  • Regular

  • Patho

    • Reentrant loop through the two pathways within AV node (see picture)

    • Usually brought on by PAC

  • EKG

    • Typical (MC): P-wave usually buried in QRS. If present, likely after QRS and inverted (retrograde conduction) in inferior leads

    • Atypical: P-wave so long after QRS that it may appear as if it is before QRS

  • TX

    • Usually cardioverts with vagal maneuvers or adenosine

  • Two pathways within the AV node: a fast one and slow one

  • If an extra signal makes it to the AV node and the fast pathway is open it will take it

  • If the slow pathway comes out of refractory while the new signal makes its way down, the signal can go back up the slow pathway

  • Then back down the fast pathway when that comes out of refractory

Atrioventricular reentry (AVRT)

  • Anatomical reentry (involving an accessory pathway)

  • Wolff-Parkinson-White (WPW) is a common cause of AVRT

  • HR 150 - 250

  • Regular

  • Patho

    • Reentrant loop:

      • one pathway AV node and other pathway is an accessory pathway

  • EKG

  • Orthodromic (MC): Orthodromic has narrow QRS

    • (because signal traveling down the septum)

    • P-wave typically buried or after QRS

  • Antidromic: Anti - going up the septum ➔ Wide QRS, Short PR

  • TX

    • Orthodromic (narrow)

      • Vagal maneuvers

      • Can give adenosine (or verapamil) but can ➔ rapid afib

      • "Second line" procainamide

    • Antidromic (wide)

      • Procainamide

      • Avoid adenosine unless positive AVRT dx

      • Telling the difference between a wide complex tachycardia of ventricular origin and antidromic AVRT is difficult

      • Adenosine shouldn't be given in ventricular tachycardias

Orthodromic (MC)

    • Atrium ➔ AV NODE ➔ ventricle (antegrade)

    • Ventricle ➔ accessory pathway ➔ atrium (retrograde)

Antidromic

    • Atrium ➔ accessory pathway ➔ ventricle (antegrade)

    • Ventricle ➔ AV node ➔ atrium (retrograde)

Wolff-Parkinson-White (WPW)

Congenital accessory pathway (bundle of Kent) ➔ ventricular preexcitation

  • Pre-excitation ➔ Delta wave (slurred upstroke at start of QRS)

    • Slurred upstroke ➔ short PR & wide QRS

    • Seen in sinus EKG (their baseline EKG)

  • Preexcitation can ➔ AVRT (Orthodromic MC), A-fib, A-flutter

TX

  • Stable

    • WPW ➔ orthodromic: Procainamide

      • Can give adenosine but can ➔ rapid afib

    • Antidromic (confirmed): can use adenosine, procainamide safer

    • AF with preexcitation: Procainamide

      • Definitely can not use av-nodal blockers (adenosine)

  • Unstable

    • **DC cardioversion if sick**

  • Ablation is definitive

  • The narrow complex in orthodromic AVRT means that the impulse coming from the atria is taking the AV node pathway

  • Since the signal is conducted up the accessory pathway (away from the ventricle) the ventricle is not pre-excited... and you don't see a ∆ wave

  • So, since orthodromic AVRT is MC in WPW... you won't see ∆ waves in WPW induced orthodromic AVRT