eMedicine Specialties > Emergency Medicine > Cardiovascular

Ventricular Tachycardia: Differential Diagnoses & Workup

Author: Ian S deSouza, MD, Assistant Professor, Department of Emergency Medicine, Kings County Hospital/SUNY Downstate Medical Centers
Coauthor(s): Che' Damon Ward, MD, Staff Physician, Department of Emergency Medicine, State University of New York Health Science Center at Brooklyn
Contributor Information and Disclosures

Updated: Sep 17, 2009

Differential Diagnoses

Atrial Fibrillation
Hypomagnesemia
Atrial Flutter
Myocardial Infarction
Automatic External Defibrillation
Pacemaker and Automatic Internal Cardiac Defibrillator
Congestive Heart Failure and Pulmonary Edema
Premature Ventricular Contraction
Hypocalcemia
Torsade de Pointes
Hypokalemia
Ventricular Fibrillation

Other Problems to Be Considered

Supraventricular tachycardia (SVT) with aberrancy
Sudden cardiac death

Workup

Laboratory Studies

  • When the patient presents with symptoms of frank hemodynamic compromise, one should defer laboratory tests until electrical cardioversion or defibrillation is performed and the patient is stabilized.
  • Assess electrolyte levels of all patients with ventricular tachycardia (VT), including serum calcium, magnesium, and phosphate levels. Ionized calcium levels are preferred over total serum calcium level. Hypokalemia, hypomagnesemia, and hypocalcemia may predispose patients to either monomorphic VT or torsade de pointes.
  • Obtain, when appropriate, levels of therapeutic drugs (eg, digoxin).
  • Evaluate for myocardial ischemia or infarction with serum cardiac troponin I or T levels or other cardiac markers.

Imaging Studies

  • Chest radiography is indicated if symptoms suggest the possibility of congestive heart failure (CHF) or other cardiopulmonary pathology as contributing factors.

Other Tests

  • ECG is the diagnostic tool of choice for confirming the presence of VT. Simultaneous 3-channel recordings and 12-lead tracings are more helpful than rhythm strips to analyze such dysrhythmias.
    • Complexes of atypical morphology often are difficult to interpret. Such tachycardias could be paroxysmal supraventricular tachycardia (PSVT) with aberrant conduction. If the patient is unstable, or differentiation between VT and SVT is uncertain, treat rhythm as VT. Recall that the vast majority of patients with wide-complex regular tachycardias will have VT. 
    • ECG criteria that support VT over SVT include AV dissociation, fusion beats at the initiation of the dysrhythmia, QRS duration over 140 ms, and RS pattern in V1, frontal QRS axis between 180 and 270 degrees, and positive or negative concordance across the precordial leads.2,3
    • ECG criteria that support SVT over VT include a right bundle branch block (RBBB) pattern when present in the native sinus rhythm, varying bundle branch block, an R or qR pattern in V1, or an ectopic P wave preceding the dysrhythmia. 

Remember, patients with underlying structural or ischemic heart disease are more likely to have VT than SVT. Historically, the use of adenosine to distinguish between regular wide-QRS complex SVTs and ventricular tachycardia has been discouraged due to the theoretical precipitation of ventricular fibrillation. However, a recent study has demonstrated that adenosine may be both useful and safe as a diagnostic agent in this differentiation.2 Adenosine through transient AV nodal blockade should terminate reentrant SVTs, which involve the AV node as a pathway (described above in Pathophysiology), but will not terminate VT.

Adenosine should NOT be used for IRREGULAR wide-QRS complex tachycardia, as this dysrhythmia may be atrial fibrillation in presence of an accessory pathway. In this particular case, adenosine may allow conduction of rapid atrial fibrillatory impulses exclusively through an amenable accessory tract to cause very rapid, intolerable ventricular rates.

More on Ventricular Tachycardia

Overview: Ventricular Tachycardia
Differential Diagnoses & Workup: Ventricular Tachycardia
Treatment & Medication: Ventricular Tachycardia
Follow-up: Ventricular Tachycardia
Multimedia: Ventricular Tachycardia
References
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References

  1. Wellens HJ, Bar FW, Lie KI. The value of the electrocardiogram in the differential diagnosis of a tachycardia with a widened QRS complex. Am J Med. Jan 1978;64(1):27-33. [Medline].

  2. Marill KA, Wolfram S, Desouza IS, Nishijima DK, Kay D, Setnik GS. Adenosine for wide-complex tachycardia: efficacy and safety. Crit Care Med. Sep 2009;37(9):2512-8. [Medline].

  3. Marill KA, deSouza IS, Nishijima DK, Stair TO, Setnik GS, Ruskin JN. Amiodarone is poorly effective for the acute termination of ventricular tachycardia. Ann Emerg Med. Mar 2006;47(3):217-24. [Medline].

  4. Tomlinson DR, Cherian P, Betts TR, Bashir Y. Intravenous amiodarone for the pharmacological termination of haemodynamically-tolerated sustained ventricular tachycardia: is bolus dose amiodarone an appropriate first-line treatment?. Emerg Med J. Jan 2008;25(1):15-8. [Medline].

  5. Buxton AE, Marchlinski FE, Doherty JU, Flores B, Josephson ME. Hazards of intravenous verapamil for sustained ventricular tachycardia. Am J Cardiol. May 1 1987;59(12):1107-10. [Medline].

  6. Turley AJ, Thambyrajah J, Harcombe AA. Bilateral thoracoscopic cervical sympathectomy for the treatment of recurrent polymorphic ventricular tachycardia. Heart. Jan 2005;91(1):15-7. [Medline].

  7. Brennan TD, Haas GJ. The role of prophylactic implantable cardioverter defibrillators in heart failure: recent trials usher in a new era of device therapy. Curr Heart Fail Rep. Mar 2005;2(1):40-5. [Medline].

  8. Francis J, Sankar V, Nair VK, et al. Catecholaminergic polymorphic ventricular tachycardia. Heart Rhythm. May 2005;2(5):550-4. [Medline].

  9. Hoffman JR, Votey SR. Tachyarrhythmias. In: The Clinical Practice of Emergency Medicine. 2nd ed. 1996:605.

  10. Hunter R. Ventricular tachycardia following naloxone administration in an illicit drug misuse. J Clin Forensic Med. Aug 2005;12(4):218-9. [Medline].

  11. Jenkins RD, Gerred SJ. ECGs by Example. Philadelphia, Pa: Elsevier Science Limited; 2002.

  12. Kliegel A, Eisenburger P, Sterz F, et al. Survivors of ventricular tachyarrhythmias due to a transient or reversible disorder have a high recurrence rate of lethal cardiac events. Resuscitation. Sep 2002;54(3):237-43. [Medline].

  13. Kudenchuk PJ, Cobb LA, Copass MK, et al. Amiodarone for resuscitation after out-of-hospital cardiac arrest due to ventricular fibrillation. N Engl J Med. Sep 16 1999;341(12):871-8. [Medline].

  14. Marriot HJ, Conover MB. Advanced Concepts in Arrhythmias. 3rd ed. Philadelphia, Pa: Mosby Inc; 1998.

  15. Part 7.3: Management of Symptomatic Bradycardia and Tachycardia. Circulation. 2005/11;112:IV-67-IV-77. [Full Text].

  16. Stevenson WG. Catheter ablation of monomorphic ventricular tachycardia. Curr Opin Cardiol. Jan 2005;20(1):42-7. [Medline].

  17. Testa A, Ojetti V, Migneco A, et al. Use of amiodarone in emergency. Eur Rev Med Pharmacol Sci. May-Jun 2005;9(3):183-90. [Medline].

  18. [Guideline] Zipes DP, Camm AJ, Borggrefe M, et al. ACC/AHA/ESC 2006 Guidelines for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death: a report of the American College of Cardiology/American Heart Association Task Force and the European Society of Cardiology Committee for Practice Guidelines (writing committee to develop Guidelines for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death): developed in collaboration with the European Heart Rhythm Association and the Heart Rhythm Society. Circulation. Sep 5 2006;114(10):e385-484. [Medline].

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Further Reading

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Keywords

ventricular tachycardia, VT, tachydysrhythmia, ventricular ectopic focus, fusion beats, atrioventricular dissociation, AV dissociation, wide QRS complexes, ventricular fibrillation, VF, paroxysmal supraventricular tachycardia, PSVT, torsade de pointes, accelerated idioventricular rhythm, congestive heart failure, pulmonary edema, jugular venous distention,hypotension, CAD, structural heart disease, hypokalemia, hypocalcemia, hypomagnesia, methamphetamine, cocaine, genetic arrhythmia syndrome, cardiac channelopathy

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Contributor Information and Disclosures

Author

Ian S deSouza, MD, Assistant Professor, Department of Emergency Medicine, Kings County Hospital/SUNY Downstate Medical Centers
Ian S deSouza, MD is a member of the following medical societies: American Academy of Emergency Medicine
Disclosure: Nothing to disclose.

Coauthor(s)

Che' Damon Ward, MD, Staff Physician, Department of Emergency Medicine, State University of New York Health Science Center at Brooklyn
Che' Damon Ward, MD is a member of the following medical societies: American Academy of Emergency Medicine and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Medical Editor

Steven A Conrad, MD, PhD, Chief, Department of Emergency Medicine; Chief, Multidisciplinary Critical Care Service, Professor, Department of Emergency and Internal Medicine, Louisiana State University Health Sciences Center
Steven A Conrad, MD, PhD is a member of the following medical societies: American College of Chest Physicians, American College of Critical Care Medicine, American College of Emergency Physicians, American College of Physicians, International Society for Heart and Lung Transplantation, Louisiana State Medical Society, Shock Society, Society for Academic Emergency Medicine, and Society of Critical Care Medicine
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

Managing Editor

Gary Setnik, MD, Chair, Department of Emergency Medicine, Mount Auburn Hospital; Assistant Professor, Division of Emergency Medicine, Harvard Medical School
Gary Setnik, MD is a member of the following medical societies: American College of Emergency Physicians, National Association of EMS Physicians, and Society for Academic Emergency Medicine
Disclosure: SironaHealth Salary Management position; South Middlesex EMS Consortium Salary Management position

CME Editor

John D Halamka, MD, MS, Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center
John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Chief Editor

David FM Brown, MD, Assistant Professor, Division of Emergency Medicine, Harvard Medical School; Vice Chair, Department of Emergency Medicine, Massachusetts General Hospital
David FM Brown, MD is a member of the following medical societies: American College of Emergency Physicians and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

 
 
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