eMedicine Specialties > Cardiology > Arrhythmias

Ashman Phenomenon

Author: Ram C Sharma, MD, MRCP, Assistant Professor of Medicine, Division of Cardiovascular Medicine, Department of Internal Medicine, University of Louisville
Coauthor(s): Roger Freedman, MD, Director of Clinical Cardiology, Professor, Department of Internal Medicine, Division of Cardiology, University of Utah School of Medicine
Contributor Information and Disclosures

Updated: May 29, 2009

Introduction

Background

Ashman phenomenon is an aberrant ventricular conduction due to a change in QRS cycle length. In 1947, Gouaux and Ashman reported that in atrial fibrillation, when a relatively long cycle was followed by a relatively short cycle, the beat with a short cycle often has right bundle-branch block (RBBB) morphology.1 This causes diagnostic confusion with premature ventricular complexes (PVCs). If a sudden lengthening of the QRS cycle occurs, the subsequent impulse with a normal or shorter cycle length may be conducted with aberrancy.

Pathophysiology

Ashman phenomenon is an intraventricular conduction abnormality caused by a change in the heart rate. This is dependent on the effects of rate on the electrophysiological properties of the heart and can be modulated by metabolic and electrolyte abnormalities and the effects of drugs.

The aberrant conduction depends on the relative refractory period of the components of the conduction system distal to the atrioventricular node. The refractory period depends on the heart rate. Action potential duration (ie, refractory period) changes with the R-R interval of the preceding cycle; shorter duration of action potential is associated with a short R-R interval and prolonged duration of action potential is associated with a long R-R interval. A longer cycle lengthens the ensuing refractory period, and, if a shorter cycle follows, the beat ending it is likely to be conducted with aberrancy.

Aberrant conduction results when a supraventricular impulse reaches the His-Purkinje system while one of its branches is still in the relative or absolute refractory period. This results in slow or blocked conduction through this bundle branch and delayed depolarization through the ventricular muscles, causing a bundle-branch block configuration (ie, wide QRS complex) on the surface ECG, in the absence of bundle-branch pathology. A RBBB pattern is more common than a left bundle-branch block (LBBB) pattern because of the longer refractory period of the right bundle branch.

Several studies have questioned the sensitivity and specificity of the long-short cycle sequence. Aberrant conduction with a short-long cycle sequence has also been documented.

Frequency

United States

No geographic variations occur. Ashman phenomenon is related to the underlying pathology and is a common ECG finding in clinical practice.

Mortality/Morbidity

Ashman phenomenon is simply an electrocardiographic manifestation of the underlying condition; therefore, the morbidity and mortality is related to the underlying condition.

Clinical

History

  • The diagnosis of Ashman phenomenon is made using ECG evaluation findings. Patients may be asymptomatic or may have symptoms of the underlying cardiac condition.
  • Ashman phenomenon, per se, causes no symptoms. Symptoms, if present, are related to the premature complexes and are not related to whether the complexes are conducted aberrantly.

Physical

  • No specific physical examination findings are described for Ashman phenomenon.
  • Pulse findings may include an irregular pulse, tachycardia, and/or pulse deficit in atrial fibrillation.

Causes

Conditions causing an altered duration of the refractory period of the bundle branch or the ventricular tissue cause Ashman phenomenon. These conditions are commonly observed in atrial fibrillation, atrial tachycardia, and atrial ectopy.

More on Ashman Phenomenon

Overview: Ashman Phenomenon
Differential Diagnoses & Workup: Ashman Phenomenon
Treatment & Medication: Ashman Phenomenon
Follow-up: Ashman Phenomenon
Multimedia: Ashman Phenomenon
References
Further Reading
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References

  1. Gouaux JL, Ashman R. Auricular fibrillation with aberration stimulating ventricular paroxysmal tachycardia. Am Heart J. 1947;34:366.

  2. Fisch C. Electrocardiography of arrhythmias: from deductive analysis to laboratory confirmation--twenty-five years of progress. J Am Coll Cardiol. Jan 1983;1(1):306-16. [Medline].

  3. Marriott HJL, Sandler JA. Criteria, old and new, for differentiating between ectopic ventricular beats and aberrant ventricular conduction in the presence of atrial fibrillation. Prog Cardiovasc Dis. 1966;9:18.

  4. Gulamhusein S, Yee R, Ko PT, Klein GJ. Electrocardiographic criteria for differentiating aberrancy and ventricular extrasystole in chronic atrial fibrillation: validation by intracardiac recordings. J Electrocardiol. Jan 1985;18(1):41-50. [Medline].

  5. Adelstein EC, Saba S. Usefulness of baseline electrocardiographic QRS complex pattern to predict response to cardiac resynchronization. Am J Cardiol. Jan 15 2009;103(2):238-42. [Medline].

  6. Antunes E, Brugada J, Steurer G, et al. The differential diagnosis of a regular tachycardia with a wide QRS complex on the 12-lead ECG: ventricular tachycardia, supraventricular tachycardia with aberrant intraventricular conduction, and supraventricular tachycardia with anterograde conducti. Pacing Clin Electrophysiol. Sep 1994;17(9):1515-24. [Medline].

  7. Chaudry II, Ramsaran EK, Spodick DH. Observations on the reliability of the Ashman phenomenon. Am Heart J. Jul 1994;128(1):205-9. [Medline].

  8. Strabuzynska-Migaj E, Szyszka A, Cieslinski A. Prolonged QRS duration in patients with heart failure: relation to exercise tolerance, diastolic function and aetiology. Kardiol Pol. Dec 2008;66(12):1251-7. [Medline].

  9. Wagner GS. Ashman phenomenon. In: Wagner GS, Marriott HJ, eds. Marriott's Practical Electrocardiography. 9th ed. Baltimore, Md: Williams & Wilkins; 1994:340.

  10. Wellens HJ. The QRS configuration during bundle branch block. What has rate got to do with it?. Eur Heart J. Oct 2008;29(19):2319-20. [Medline].

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Keywords

aberrant ventricular conduction, aberrant conduction, right bundle-branch block morphology, RBBB morphology, intraventricular conduction abnormality, premature ventricular complexes, PVCs

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Contributor Information and Disclosures

Author

Ram C Sharma, MD, MRCP, Assistant Professor of Medicine, Division of Cardiovascular Medicine, Department of Internal Medicine, University of Louisville
Ram C Sharma, MD, MRCP is a member of the following medical societies: American Academy of Sleep Medicine, American College of Cardiology, and Royal College of Physicians of the United Kingdom
Disclosure: Nothing to disclose.

Coauthor(s)

Roger Freedman, MD, Director of Clinical Cardiology, Professor, Department of Internal Medicine, Division of Cardiology, University of Utah School of Medicine
Roger Freedman, MD is a member of the following medical societies: American College of Cardiology, American College of Physicians, American Heart Association, Heart Rhythm Society, Phi Beta Kappa, and Sigma Xi
Disclosure: St. Jude Medical Grant/research funds Other; St. Jude Medical Consulting fee Consulting; St. Jude Medical Ownership interest Other; Boston Scientific Grant/research funds Other; Boston Scientific Consulting fee Consulting; Medtronic Grant/research funds Other; Medtronic  Consulting; Sorin Consulting fee Consulting

Medical Editor

Russell F Kelly, MD, Program Director, Assistant Professor, Department of Internal Medicine, Division of Cardiology, Cook County Hospital, Rush Medical College
Russell F Kelly, MD is a member of the following medical societies: American College of Cardiology
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.

Managing Editor

Brian Olshansky, MD, Professor of Medicine, Department of Internal Medicine, University of Iowa College of Medicine
Brian Olshansky, MD is a member of the following medical societies: American Autonomic Society, American College of Cardiology, American College of Chest Physicians, American College of Physicians, American College of Sports Medicine, American Federation for Clinical Research, American Heart Association, Cardiac Electrophysiology Society, Heart Rhythm Society, and New York Academy of Sciences
Disclosure: Guidant/Boston Scientific Honoraria Speaking and teaching; Medtronic Honoraria Speaking and teaching; Guidant/Boston Scientific Consulting fee Consulting; Reliant Grant/research funds Other; Novartis Honoraria Speaking and teaching; Novartis Consulting fee Consulting

CME Editor

Amer Suleman, MD, Consultant in Electrophysiology and Cardiovascular Medicine, Department of Internal Medicine, Division of Cardiology, Medical City Dallas Hospital
Amer Suleman, MD is a member of the following medical societies: American College of Physicians, American Heart Association, American Institute of Stress, American Society of Hypertension, Federation of American Societies for Experimental Biology, Royal Society of Medicine, and Society of Cardiac Angiography and Interventions
Disclosure: Nothing to disclose.

Chief Editor

Jeffrey N Rottman, MD, Professor of Medicine and Pharmacology, Director, Clinical Cardiac Electrophysiology Fellowship Program, Vanderbilt University School of Medicine; Chief, Department of Cardiology, Nashville Veterans Affairs Medical Center
Jeffrey N Rottman, MD is a member of the following medical societies: American Heart Association and North American Society of Pacing and Electrophysiology (NASPE)
Disclosure: Nothing to disclose.

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