Jay GreenEmergency Medicine Resident, PGY-3

July 24, 2008

Regular WCT

VT (monomorphic) SVT + accessory pathway SVT + BBB SVT with a Na channel

blocker

Irregular WCT

Polymorphic VT Torsades de Pointes

A fib + accessory pathway A fib + BBB A flutter + variable block +

BBB MAT + BBB V Fib

ObjectivesImprove our ability to distinguish various WCT

An Approach to WCT (Is the patient stable or unstable?)

What is the rate?

Is the rhythm regular or irregular?

Are there p waves? Are they related to the QRS? Are they flutter waves? Are the p waves of the same morphology?

Is the QRS morphology consistent?

35M palpitations, lightheaded

Irregular WCT, marked variation in QRS morphology, no P waves = AF + WPW

Wolff-Parkinson-White Syndrome Most common ventricular pre-excitation

syndrome (bundle of Kent) Triad:

Short PR (<0.12 sec)QRS prolongation (>0.10 sec)Slurred QRS upstroke (delta wave)

If WCTRates can approach 300bpmSignificant QRS morphology variation

57M weakness, palpitations

Irregular WCT, consistent QRS morphology, no P waves = AF + RBBB

44M chronic alcoholic, unresponsive

Irregular WCT, varying QRS morphology (undulating) = Torsades de Pointes

47M palpitations

Irregular WCT, consistent QRS morphology, P waves, consistent R-R in groups = A flutter + variable block + RBBB

60M dyspnea, palpitations, hx COPD

Irregular WCT, consistent QRS morphology, irregular P waves, inconsistent R-R = MAT + RBBB

Summary Irregular WCT – The Bad AF + WPW

QRS morphology variationRates can approach 300bpm

AF + BBBConsistent QRS morphologyRate limited by AV node (usually < 200bpm)

Polymorphic VTQRS morphology variation (more chaotic

than WPW)Rates consistently rapid (often > 300bpm)Unstable

Summary Irregular WCT – The Good Atrial flutter with variable block + BBB

P waves present, some not conductedConsistent QRS morphologyConsistent R-R interval in groups

MAT + BBBIrregular P waves of different morphologyConsistent QRS morphologyInconsistent R-R interval

41M weakness

Irregular wide complex rhythm, peaked T, no P = hyperkalemia

ECG Findings in Hyperkalemia Peaked T-waves (>5mm) QT shortening ST elevation Increased PR/loss of P wave Widening/Slurring QRS Sine wave appearance

Potentially mistaken for VT 2nd/3rd degree block, VF, asystole

72F SOB, PMH: recent MI

Regular WCT, AV dissociation & fusion beat (rhythm strip), capture beat (V1) = VT

61M fever, cough, dyspnea

Regular WCT, P waves in V1 = atrial tachycardia + LBBB

VT vs. SVT With Abberancy Angina, MI, CABG, valvular dz, or CHF

PPV 95% for VT Hemodynamic stability not useful ECG findings

A-V dissociation (discernable in 20%)○ PPV 100%○ AV association not helpful (present in 50% VT)

Fusion beats, capture beats (discernable in 5-10%)○ PPV 100%

VT vs. SVT With Abberancy Wellens criteria

Many criteria Wellens HJJ, Bar FWHM, Lie KI. The value of the electrocardiogram in the differential diagnosis of a

tachycardia with a widened QRS complex. Am J Med 1978;64:27-33.

Brugada criteria4-step approach using WellensSN 98.7%, SP 96.5% for VT (original study)

○ Brugada P: A new approach to the differential diagnosis of a regular tachycardia with a wide QRS complex, Circulation 83:1649, 1991.

EP’s: SN 79-83%, SP 43-70%, K = 0.54-058○ Isenhour et al. Wide Complex tachycardia: continued evaluation of diagnostic criteria.

Academic Emergency Medicine. Jul 2000;7(7): 769-773.○ Herbert et al. Failure to agree on the electrocardiographic diagnosis of ventricular

tachycardia. Ann Emerg Med. 1996;27(1):35-8.

Summary Regular WCT VT

Fusion beats, capture beats, AV dissociationPMH: cardiac disease

SVT + BBBAbsence of fusion/capture beats and AV dissociationPre-existing BBB

SVT + accessory pathwayAbsence of fusion/capture beats and AV dissociationPre-existing accessory pathway

SVT + Na channel blocker

64F SOB, hypotension, PMH: a fib

Regular WCT, bidirectional = Digoxin toxicity

Questions?

More practice

60 M with CP and hypotension

Irregular WCT, rate > 250, inconsistent QRS morphology = AF + WPW

62F palpitations

Irregular WCT, consistent QRS morphology = AF + RBBB

63F syncope, PMH: DM & arthritis

Hyperkalemia

43M severe palpitations

Regular WCT, no P waves = presumed VT What if old ECG with pre-existing RBBB? = SVT

62F lightheaded, PMH: MI x 2

Regular WCT, no P waves = VT

61M palpitations, lightheaded

Regular WCT, AV dissociation in V1 & II = VT

74M CP, palpitations

Regular WCT, no P waves, fusion beat = VT

Fusion beatRhythm strip