Ventricular Tachycardia
Ventricular tachycardia is defined as an arrhythmia which originates from the ventricles consisting of at least three or more consecutive beats at a rate of greater than 100/min and independent of AV or atrial conduction. If this terminates spontaneously
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Ventricular Tachycardia Benedict M. Glover and Pedro Brugada
Abstract Ventricular tachycardia is defined as an arrhythmia which originates from the ventricles consisting of at least three or more consecutive beats at a rate of greater than 100/min and independent of AV or atrial conduction. If this terminates spontaneously within less than 30 s it is defined as non-sustained. If it lasts greater than 30 s or requires treatment for termination it is defined as sustained. Most commonly VT is associated with structural heart disease such as scar related re-entry in patients who have had a prior MI. Occasionally it may be associated with a structurally normal heart and is termed idiopathic. This is most commonly seen in the right ventricular outflow tract, coronary cusps, coronary veins or around the valve annuli.
ECG Criteria One of the most important issues is to record an ECG during tachycardia in order to help make a diagnosis as to whether the arrhythmia is ventricular or supraventricular and if ventricular where the exit site may be located. As shown in Fig. 9.1 several criteria exist in order to help make this differentiation. The Brugada criteria uses a straightforward and stepwise approach. This was developed by examining 348 cases of VT and comparing these with 170 cases of SVT with abberancy [1]. No patients were receiving anti-arrhythmic drugs. The first step looks at the absence of an RS in all of the precordial leads. If this is the case B.M. Glover (*) Department of Cardiac Electrophysiology, Queens University, Kingston, ON, Canada e-mail: [email protected] P. Brugada, MD, PhD Chairman, Cardiovascular Division, Free University of Brussels UZ Brussel-VUB, Brussels, Belgium GVM Group, Cotignola, Italy CEO Medisch Centrum Prof. Dr. P. Brugada, Aalst, Belgium Clinical Electrophysiology Program, Hospiten Estepona, Marbella, Spain © Springer International Publishing Switzerland 2016 B.M. Glover, P. Brugada (eds.), Clinical Handbook of Cardiac Electrophysiology, DOI 10.1007/978-3-319-40818-7_9
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B.M. Glover and P. Brugada
Fig. 9.1 Brugada Criteria, Wellens Criteria and Vereckei Criteria for the diagnosis of VT (Reproduced with permission from Alzand and Crijns [15]. Oxford University Press)
then VT is diagnosed. If not then the longest RS interval is examined and if greater than 100 ms VT is diagnosed. If not the presence of AV dissociation is looked for. As VA conduction may occur in almost half of all cases of VT it is important not to confuse 1:1 VA conduction with a supraventricular arrhythmia with 1:1 A:V conduction or 2:1 VA conduction during VT with AV dissociation. If this is not seen then the classical Wellens criteria for VT in leads V1 or V2 as well as V6 are looked for [2]. These include a QR, R or RSr’ in V1 or V2 with an RS less than 1 in V6 or a QS in V6 in a RBBB morphology or an R in V1 greater than 30 ms with notching of the S wave and an onset of QRS to S wave of greater than 70 ms in V1 or V2 with a Q wave in V6 in a LBBB morphology. Another interesting algorithm has also
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