Ventricular tachycardia Microchapters Home Patient Information Overview Historical Perspective Classification Pathophysiology Causes Differentiating Ventricular Tachycardia from other Disorders Epidemiology and Demographics Risk Factors Screening Natural History, Complications and Prognosis Diagnosis Diagnostic Study of Choice History and Symptoms Physical Examination Laboratory Findings Electrocardiogram Chest X Ray Echocardiography Cardiac MRI Other Diagnostic Tests Treatment Medical Therapy Electrical Cardioversion Ablation Surgery Primary Prevention Secondary Prevention Cost-Effectiveness of Therapy Future or Investigational Therapies Case Studies Case #1 Ventricular tachycardia electrocardiogram On the Web Most recent articles Most cited articles Review articles CME Programs Powerpoint slides Images Ongoing Trials at Clinical Trials.gov US National Guidelines Clearinghouse NICE Guidance FDA on Ventricular tachycardia electrocardiogram CDC onVentricular tachycardia electrocardiogram Ventricular tachycardia electrocardiogram in the news Blogs on Ventricular tachycardia electrocardiogram to Hospitals Treating Ventricular tachycardia electrocardiogram Risk calculators and risk factors for Ventricular tachycardia electrocardiogram Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-in Chief: Sara Zand, M.D.[2] Avirup Guha, M.B.B.S.[3]; Priyamvada Singh, M.D. [4] ## Overview[edit | edit source] Finding on ECG associated with VT include: AV dissociation, atypical right bundle branch block or left bundle branch block characteristics, QRS> 140 ms for wide complex tachycardia with right bundle branch block pattern and QRS > 160 ms for wide complex tachycardia with left bundle branch block pattern, concordance or same polarity in all precordioal leads, rightward superior QRS axis. ## Electrocardiogram[edit | edit source] Common ECG criteria associated with VT include:[1] * Atrioventricular dissociation * The key diagnostic criterion for VT especially when the ventricular rate exceeds the atrial rate * The absence of AV dissociation does not rule out VT * The series of QRS complexes uncoupled from dissociated P waves * Limiting the atrial rhythm by self‐governing ventricular rhythm * Capture beat or single QRS complex resembling the patient's baseline rhythm due to stopping ventricular depolarization by supraventricular impulse * Fusion beat or a hybrid QRS complex resembling the ventricular depolarization characteristics of the VT and baseline rhythm * If ventricular impulses conduct retrograde through the His‐Purkinje system to depolarize the atria, VT will not exhibit atrioventricular dissociation. * Morphologic criteria * VT is the most likely diagnosis if a wide QRS tachycardia demonstrates a QRS patten incompatible with typical right or left bundle branch block characteristics. * In the presence of wide QRS tachycardia with atypical right bundle block characteristics including monophasic R wave in V1 or V2 and QS pattern in V6, VT is the most likely diagnosis. * When there is wide complex tachycardia with classic left bundle branch block pattern ( r wave onset to S wave nadir <60 ms in V1 or V2 and notched monophasic R wave in V6), supraventricular tachycardia is the most likely diagnosis. * QRS duration * QRS >140 ms for wide complex tachycardia with right bundle branch block pattern and QRS >160 ms for wide complex tachycardia with left bundle branch block pattern indicating ventricular tachycardia. * QRS >160 ms may also be seen in supraventricular tachycardia especially among patients with ongoing antiarrhythmic use, electrolyte disturbances, conduction delays, or severe underlying structural heart disease or cardiomyopathies. * Fascicular VT may demonstrate substantial impulse propagation within the conduction system with QRS durations <120 ms * Chest Lead Concordance * QRS complexes in all 6 precordial leads (V1–V6) uniformly shown a monophasic pattern with same polarity ( R for positive concordance and QS for negative concordance) * Wide complex tachycardias with positive concordance demonstrating VT originating from the posterobasal left ventricle. * Wide complex tachycardias with negative concordance may arise from VT originating for the anteroapical left ventricle * Absence of concordance does not rule out VT diagnosis. * QRS Axis * Rightward superior QRS axis ( northwest axis) between −90° and −180° * Dominant R wave in lead avR * Coexistence of left‐ or right‐axis deviation with right or left bundle branch block * In the presence of scar‐related VT mapped to the anterolateral wall of the left ventricle may show a wide complex tachycardia with an atypical right bundle branch block pattern and rightward and superior QRS axix which is uncommon in supraventricular tachycardia with right bundle branch block aberrancy. * Differences in Ventricular Activation Velocity * slurred initial components of the QRS complex due to slower cardiomyocyte‐to‐cardiomyocyte conduction ( R wave peak time in lead II ≥50 ms, or RS interval ≥100 ms in any of the precordial leads [V1–V6]) * Rapid propagates from conduction system and activation the remainder of the myocardium * Rapid or sharper deflections in the terminal portion of QRS complex ( the ratio of the voltage excursion during the initial [Vi] and terminal [Vt] 40 ms of the QRS complex <1) * Comparison to the baseline ECG * Findings the changes in the QRS axis, T axis, and QRS duration between wide complex tachycardia and baseline ECG ( an ECG taken before or after tachycardia maybe helpful for diagnosis of VT. | Limb leads algorithm * Monophasic R wave in avR * Negative QRS in 2,3, avF * Opposing QRS in limb leads | | | | | | | | | | | | | | | | RWPT algorithm * R wave peak time ≥50 ms in lead 2 | The VT score * Initial R wave in V1 (+1) * Initial r wave>40 ms in V1-V2 (+1) * Notched S in V1 (+1) * Initial R in avR (+1) * RWPT≥50ms in lead 2 (+1) * NO RS inV1-V6 (+1) * AV dissiciation(+2) * ≥3, 99.6% specific for VT | Brugada algorithm * NO RS in V1-V6 * RS interval>100 ms in one precordial lead * AV dissociation * VT morphology criteria in V1,V2,V6 | Ventricular tachycardia algorithm| | Vereckie avR algorithm * Initial dominant R wave * Initial r or q wave>40 ms * Notched downstroke of negative QRS * Vi