3. Conduction Emergencies

Canadian Syncope Risk Score

<1 → discharge

1-3 → admit if unstable or unresolved sx

>4 → admit

explain axis deviation

• I UP & aVR DOWN → Leaving each other → Left

• I DOWN & aVR UP → Reach for each other → Right

• Both UP → 2 thumbs up → normal

SVT treatment

Pediatrics

• 1st line = Valsalva Maneuver

• 2nd line: Adenosine
  

Adults

• Adenosine

• Refractory: Beta Blockers or Calcium Channel Blockers

Afib/Aflutter Rate Control

Rate Control

• Beta-1 Selective Beta-Blockers → Metoprolol, Esmolol

• Non-dihydropyridine calcium channel blockers (NCCB) → Diltiazem (less bronchospams risk)

• Digitalis glycosides (Digoxin)

  • if refractory to BB or NCCB

• Amiodarone

  • if refractory to BB or NCCB

3 bolus q5min, usually done if pt not candidate for immediate electrical cardioversion (more than 48hr)

Afib/Aflutter Rhythm Control

Criteria for ED Cardioversion

• new onset AF w/in 48hr

• CHA2DS2-VASc score less than 1

= anticoag before cardioversion and after x 4 weeks

Delayed Cardioversion

• AF > 48hr but less than 1 year

= anticoag for 3-4 wk first, then cardiovert, then anticoag 4 weeks after

Electrical Cardioversion

Pharmaceutical Cardioversion → Flecainide. Propafenone, Procainamide, Amiodarone

CHA2DS2-VASc score

Consider anticoagulation if:

• Males: score > 2

• Females: score >3

Anticoagulation Options

• Heparin: periprocedural

• DOAC: mainstay for outpatient stroke prevention

• Warfarin: mechanical heal valves

who gets admitted w/ afib

• Unsuccessful rate or rhythm control

• Symptomatic

• Unstable

tx wide regular ventricular tachycardia (monomorphic)

▸ Stable

• 1st line: Procainamide

• 2nd-line: Amiodarone

▸ Unstable

• Synchronized Cardioversion

tx wide irregular ventricular tachycardia (polymorphic)

▸ Stable

• 1st line: Correct Electrolytes (MgSO4 IV)

• 2nd line: Ventricular overdrive pacing

• 3rd-line: Unsynchronized cardioversion

▸ Unstable

• Unsynchronized cardioversion

who gets admitted w/ Ventricular Tachycardia

all get admitted

tx AV Block: 1st Degree or 2nd Degree Type I

• Identify and correct any acquired pathogenesis

• Require cardiology consultation if pathological

tx AV Block: 2nd Degree Type II or 3rd Degree

cardio consult to correct pathologic causation or place ICD

who gets admitted w/ AV blocks

• 2nd Degree Type II or 3rd Degree

• Symptomatic

• Pathological pathogenesis

ECG findings in right bundle branch

• RSR’ pattern on the right side of the heart → V1 & V2 shows a conduction delay → “bunny ears”

• Reciprocal Deep S on left side of the heart → V5 & V6→ “slurred S”

ECG findings in left bundle branch

• RSR’ pattern on the left side of the heart → V5 & V6 → broad monomorphic wave, "clumsy" not smooth

• Reciprocal Deep S on right side of the heart → V1 & V2

normal QT interval

~ little over 2 large boxes (<440ms)

from start of Q wave to end of T wave

what can cause prolonged QT and short QT

long - hypokalemia, hypocalcemia, hypothermia, MVP, ICP

short - hyperkalemia, hyperthermia, acidosis

what arrhythmias ca prolonged QT or short QT progress to?

long - Torsades

short - ventricular fibrillation

tx and dispo for prolonged or shortened QT syndrome

correct acquired pathologies & cardio consult for ICD if congenital

admission if symptomatic or congenital pathogenesis

ECG findings in right ventricular hypertrophy

Tall R waves in V1, V2, V3 (right side of heart)

Reciprocal Deep S in V4, V5, V6

ECG findings in left ventricular hypertrophy

Tall R waves in V4, V5, V6 (left side of heart)

Reciprocal Deep S in V1, V2, V3

ECG findings in hypertrophic cardiomyopathy (HCM)

Needle-Q’s or Daggers of Death → Deep narrow and sharp Q waves in lateral leads (I, aVL, V5-6)

Tall R waves on left side (V5, V6) and Deep S in right side (V1, V2, V3)

murmur in Hypertrophic Obstructive Cardiomyopathy (HOCM)

• Harsh mid-systolic crescendo-decrescendo murmur

• Increased with Valsalva or Exertion (preload dependent)

• Decreases with Squatting (increases afterload and forces tract open)

Echo finding in HOCM

Myocardial thickness > 15mm

tx for HOCM

Increase preload (to keep track open) → NS or LR IV

Increase ventricular filling (slow down heart) → Labetalol IV bolus

Increase afterload (keep track open) → Phenylephrine IV

Surgical intervention

• Cardiology consultation → ICD

• Cardiothoracic surgery consultation → Myectomy (if significant)

who gets admitted with HOCM, ARVD, Brugada Syndrome, or AVRT?

symptomatic or new diagnosis

ECG finding in Arrhythmogenic Right Ventricular Dysplasia (ARVD)

Epsilon Wave (fat deposition in myocardium → conduction delay)

• small deflection “blip” at the at the end of QRS complex, just before T wave

T wave inversion and prolonged QRS in V1-V3 (right side of heart)

tx for Arrhythmogenic Right Ventricular Dysplasia (ARVD)

Dual Rate and Rhythm Control → Sotalol or Amiodarone IV

Rate Control (BB) → Metoprolol IV or Esmolol IV

causes of Brugada Syndrome and precipitating agents

autosomal dominant inheritance or sodium channelopathy → loss of function of Na+ channels

sedation (propofol, ketamine)

Na channel blockers (procainamide, flecainide)

Antipsychotics or depressants (SSRI’s, TCA’s, Lithium)

nocturnal agonal respirations and no chest pain

Brugada Syndrome

ECG finding in Brugada Syndrome

Saddleback or Covered ST Segment Elevation in V1-V3

also has J point elevation

tx for Brugada Syndrome

electrical cardioversion to fix tachydysrhythmias

cardio consult for ICD

ECG of Lown-Ganong-Levine Syndrome

• Narrow PR interval < 3 small boxes

• Narrow QRS < 1.5 small boxes

• tachycardia

ECG finding in WPW Syndrome

Delta waves = slurred, slow upstroke in the initial part of the QRS complex

when is WPW presentation most common

children

congenital pre-excitation syndrome

tx AVRT

stable pt → Procainamide IV

• CI: prolonged QT

unstable pt → Synchronized Cardioversion

Avoid all AV node blocking agents (Digoxin,  BB, CCB)