Wide QRS complex tachycardia is a common arrhythmia in clinical practice and often presents a diagnostic challenge. Wide QRS complex tachycardia may be defined as tachycardia having QRS duration of greater than 120 ms (0.12 second), the upper limit of normal QRS duration.<sup>13 Goldman M.J. Definitions of electrocardiographic configurations Principles of Clinical Electrocardiography Los Altos, CA: Lange (1973). 

Cliccare qui per andare alla sezione Riferimenti</sup> In dealing with a wide QRS complex tachycardia, it is important to decide whether it is ventricular tachycardia (VT), supraventricular tachycardia (SVT) with aberrancy (usually functional right or left bundle-branch block), or a preexcited tachycardia using an accessory atrioventricular (AV) pathway to activate the ventricles. The problem is not merely academic because incorrect diagnosis can lead to inappropriate therapy and potentially lethal consequences, especially if VT is misdiagnosed as SVT.<sup>7 Buxton A.E., Marchlinsky F.E., Doherty J.U. , e al. Hazards of intravenous verapamil for sustained ventricular tachycardia Am J Cardiol 1987 ;  59 : 1107-1110  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 42 Stewart R.B., Brady G.H., Greene H.L. Wide complex tachycardia: Misdiagnosis and outcome after emergent therapy Ann Intern Med 1986 ;  104 : 766-771

Cliccare qui per andare alla sezione Riferimenti</sup>

Despite availability of clinical and electrocardiogram (ECG) criteria, the underlying mechanism often is misdiagnosed.<sup>1 Akhtar M. Electrophysiological bases for wide QRS complex tachycardia Pacing Clin Electrophysiol 1983 ;  6 : 81-98

Cliccare qui per andare alla sezione Riferimenti, 3 Akhtar M., Shenasa M., Jazayeri M. , e al. Wide QRS complex tachycardia, reappraisal of a common clinical problem Ann Intern Med 1988 ;  109 : 905-912

Cliccare qui per andare alla sezione Riferimenti, 11 Dongas J., Lehmann M.H., Mahmud R. , e al. Value of preexisting bundle branch block in the electrocardiographic differentiation of supraventricular from ventricular origin of wide QRS tachycardia Am J Cardiol 1985 ;  55 : 717-721  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 21 Kindwall K.E., Brown J., Josephson M.E. Electrocardiographic criteria for ventricular tachycardia in wide complex left bundle branch block morphology tachycardias Am J Cardiol 1988 ;  6 : 1279-1283  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 26 Marriott H.J. Differential diagnosis of supraventricular and ventricular tachycardia Geriatrics 1970 ;  25 : 91-101

Cliccare qui per andare alla sezione Riferimenti, 28 Morady F., Baerman J.M., Dicarlo L.A. , e al. A prevalent misconception regarding wide-complex tachycardias JAMA 1985 ;  254 : 2790-2792

Cliccare qui per andare alla sezione Riferimenti, 30 Pick A., Langendorf R. Differentiation of supraventricular and ventricular tachycardia Prog Cardiovasc Dis 1960 ;  2 : 391-407  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 40 Slama R., Motte G., Coumel P. , e al. Les tachycardies junctionelles avec aberration ventriculaires et bloc complete retrograde (pseudo tachycardie ventriculaire) Arch Mal Coeur 1971 ;  64 : 691-700

Cliccare qui per andare alla sezione Riferimenti, 44 Tchou P., Young P., Mahmud R. , e al. Useful clinical criteria for the diagnosis of ventricular tachycardia Am J Med 1988 ;  84 : 53-56  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 48 Wellens H.J.J., Bar F.W., Lie K.I. The value of the electrogram in the differential diagnosis of a tachycardia with a widened QRS complex Am J Med 1978 ;  64 : 27-32  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 49 Wellens H.J.J., Brugada P. Diagnosis of ventricular tachycardia from the 12-lead electrocardiogram Cardiol Clin 1987 ;  5 : 511-525

Cliccare qui per andare alla sezione Riferimenti, 50 Wilson W.S., Judge R.D., Siegel J.K. A simple diagnostic sign in ventricular tachycardia N Engl J Med 1964 ;  270 : 446-448  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> It is important to distinguish SVT, which generally carries a good prognosis, from VT, which can be life-threatening if not managed properly. Morady et al<sup>28 Morady F., Baerman J.M., Dicarlo L.A. , e al. A prevalent misconception regarding wide-complex tachycardias JAMA 1985 ;  254 : 2790-2792

Cliccare qui per andare alla sezione Riferimenti</sup> have shown that physicians tend to underdiagnose VT and favor a diagnosis of SVT with aberrancy when patients are hemodynamically stable. In a study by Akhtar et al,<sup>3 Akhtar M., Shenasa M., Jazayeri M. , e al. Wide QRS complex tachycardia, reappraisal of a common clinical problem Ann Intern Med 1988 ;  109 : 905-912

Cliccare qui per andare alla sezione Riferimenti</sup> clinicians diagnosed VT in only 32% of patients who presented with a wide QRS tachycardia, when in fact VT was much more common.