In a patient with wide-complex tachycardia, the presence of all of the following in the ECG indicates ventricular tachycardia except
Answer is C (Typical right bundle branch block) Wide complex tachycardia due to ventricular tachycardia (VT) is characterized by bizzare QRS pattern that does not mimic typical RBBB or LBBB QRS complexes The presence of wide QRS complex tachycardia with typical RBBB or LBBB suggests supraventricular tachycardia with aberrant conduction. Wide complex tachycardia (QRS duration >deg12 seconds) Wide complex tachycardia is defined as tachyarrhythmia with a QRS duration greater than 0.12 seconds with a hea rate > 100/min Wide complex tachycardia may occurs as a result either from a ventricular (VT) or supraventricular mechanism (SVT with aberrancy) 80% of cases " align="left" height="66" width="237">Distinguishing Features between Broad complex tachycardia due to VT and SVT with aberrancy Differentiating features Ventricular Tachycardia Supraventricular Tachycardia with Abaerrancy * QRS duration Broad complex Tachycardia with QRS duration usually greater that 0.14 seconds QRS 0.14 sec Broad complex tachycardia with QRS duration usually between 0.12 sec to 0.14 seconds QRS 0.14 sec. * Fusion Beats Characteristic of VT Absent * Capture Beats Characteristic of VT Unusual * AV dissociation Characteristic of VT Absent * Independent P waves May be seen Independent P waves when present are characteristic of VT and indicate AV dissociation Independent P work's are not seen P wave and QRS complex are linked to suggest that ventricular activation depends on atrial discharge * QRS pattern QRS pattern does not resemble /mimic typical LBBB or RBBB QRS pattern often resembles /mimics typical LBBB or RBBB * Axis (Frontal plane QRS) Left axis detion (< - 30deg) Normal or Right ward * QRS morphology in V1 Monophasic or Biphasic Triphasic * R/S Ratio in V6 <1 > I * Vagal manuvre.s. No effect Slowing or termination of tachycardia by vagal manuvres
Atrioventricular dissociation
Fusion beats
Typical right bundle branch block
Capture beats