Sandbox/WCT 1

Identify cardinal findings that increase the pretest probability of wide complex tachycardia ❑ Palpitations ❑ QRS complex > 120 ms ❑ Heart rate > 150 beats/min

Does the patient have any of the following findings that require urgent cardioversion? ❑ Hemodynamic instability ❑ Hypotension ❑ Cold extremities ❑ Peripheral cyanosis ❑ Mottling ❑ Altered mental status ❑ Chest discomfort suggestive of ischemia ❑ Decompensated heart failure

❑ Yes

❑ No

❑ Continue with the complete diagnostic approach below

Prepare the patient for immediate cardioversion and simultaneously do the following: ❑ Maintain patent airway; assist breathing as necessary ❑ Adminster oxygen (if the patient is hypoxemic) ❑ Cardiac monitor to identify rhythm; monitor blood pressure and oximetry ❑ Give IV sedation if the patient is conscious (don't delay cardioversion to sedate the patient) ❑ Consider expert consultation

VT/VF in the form of cardiac arrest Click here for Cardiac arrest resident survival guide

Unsynchronized cardioversion ❑ If a patient has polymorphic VT and is unstable, treat the rhythm as VF and deliver high-energy unsynchronized shocks ❑ Provide an initial shock of 200 Joules ❑ Increase the dose if no response to the first shock (eg, 300 J, 360 J, 360 J)

Synchronized cardioversion

Atrial fibrillation with aberrancy ❑ Provide an initial dose of biphasic cardioversion of 120-200 Joules (Class IIa, level of evidence A) ❑ If the initial shock fails, increase the dose in a stepwise fashion

Arial flutter and other SVTs with aberrancy ❑ Provide an initial dose of biphasic cardioversion of 50-100 Joules (Class IIa, level of evidence B) ❑ If the initial shock fails, increase the dose in a stepwise fashion ❑ If monophasic wave form is used, begin at 200 Joules and increase in stepwise fashion if not successful

Monomorphic VT (regular form and rate) ❑ Provide an initial dose of biphasic cardioversion of 100 Joules (Class IIb, level of evidence C) ❑ If the initial shock fails, increase the dose in a stepwise fashion

❑ After the stabilization of the patient, continue with the complete diagnostic approach below

Abbreviations: ECG: electrocardiogram; VT: ventricular tachycardia; VF: ventricular fibrillation; ICD: implantable cardioverter-defibrillator; BPM: beat per minute

Characterize the symptoms: ❑ Palpitations ❑ Lightheadedness ❑ Dyspnea ❑ Diaphoresis ❑ Chest discomfort ❑ Shock ❑ Syncope ❑ Seizures ❑ Cardiac arrest Characterize the timing of the symptoms: ❑ Onset ❑ First episode ❑ Recurrent ❑ Duration ❑ Frequency ❑ Termination of the episode ❑ Spontaneous ❑ Medication use ❑ Not terminated

Identify possible triggers: ❑ Infection ❑ Caffeine ❑ Alcohol ❑ Nicotine ❑ Recreational drugs ❑ Hypovolemia ❑ Hyperthyroidism ❑ Hypoxia ❑ Acidosis ❑ Hypokalemia ❑ Hyperkalemia ❑ Hypoglycemia ❑ Hypothermia ❑ Toxins ❑ Pulmonary embolism ❑ Coronary thrombosis ❑ Cardiac tamponade ❑ Trauma

Examine the patient: Vitals ❑ Pulse ❑ Rate ❑ Tachycardia (> 100 bpm) ❑ Rhythm ❑ Regular ❑ Irregular ❑ Strength ❑ Weak ❑ Alternating in strength (atrial fibrillation with aberrancy) ❑ Respiration ❑ Tachypnea ❑ Blood pressure ❑ Hypotension (in hemodynamically unstable patients) ❑ Marked fluctuation of blood pressure (suggestive of AV dissociation in VT) Neck ❑ Canon A waves on examining the jugular venous pressure of the neck (suggestive of AV dissociation in VT) Cardiovascular examination ❑ Auscultation ❑ Heart sounds ❑ Rapid regular or irregular beats ❑ Murmurs (suggestive of valvular diseases) ❑ Variability in the occurrence and the intensity of heart sounds especially S1 (suggestive of AV dissociation in VT) ❑ Inspection ❑ Midsternal incision (sugestive of previous cardiothoracic surgery) ❑ Palpation ❑ Pace maker or ICD are usually palpapable on the left pectoral area

Order labs and tests: ❑ Order and monitor the ECG Perform urgent cardioversion in unstable patients ❑ Chest x ray ❑ Cardiomegaly (suggestive of heart disease) ❑ Pace maker and ICD appear in the x ray ❑ Invasive electrophysiological studies ❑ Electrolytes ❑ Hypomagnesemia ❑ Hypokalemia ❑ Plasma concentration of drugs (eg,digoxin, quinidine or procainamide

Wide QRS complex tachycardia (QRS duration greater than 120 ms)

Regular or irregular?

Regular

Irregular

Is QRS identical to that during SR? If yes, consider: - SVT and BBB - Antidromic AVRT

Atrial fibrillation Atrial flutter / AT with variable conduction and: a) BBB or b) Antegrade conduction via AP

Vagal maneuvers or adenosine

Previous myocardial infarction or structural heart disease? If yes, VT is likely.

1 to 1 AV relationship?

Yes or unknown

No

V rate faster than A rate

A rate faster than V rate

QRS morphology in precordial leads

VT

Atrial tachycardia Atrial flutter

Typical RBBB or LBBB

Precordial leads: - Concordant - No R/S pattern - Onset of R to nadir longer than 100ms

RBBB pattern: - qR, Rs or Rr' in V1 - Frontal plane axis range from +90 degrees to -90 degrees

LBBB pattern: - R in V1 longer than 30 ms - R to nadir of S in V1 greater than 60 ms - qR or qS in V6

SVT

VT

VT

VT

The above algorithm is adapted from the 2003 American College of Cardiology.