Osborn waves in sepsis.

Abstract: A patient with severe sepsis, who presented with moderate hypothermia and the classical electrocardiographic findings that have been described in patients with accidental hypothermia is presented. Rewarming was associated with proportional improvement of the initial electrocardiographic abnormalities. A brief discussion is included about the electrophysiologic mechanisms of Osborn waves, the differential diagnosis of this electrocardiographic finding as well as other findings described in patients with hypothermia.

Key Words: hypothermia, Osborn waves, J waves, sepsis

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Case Report

A 68-year-old female with stage 4 chronic kidney disease (glomerular filtration rate 27 mL/min per 1.73 [m.sup.2]), chronic normocytic anemia and mild Crohn disease in prolonged remission was hospitalized after having been found unresponsive and hypothermic due to septic shock. The initial electrocardiogram revealed prominent Osborn waves as well as other findings characteristic of hypothermia, including sinus bradycardia and prolonged PR, QRS and corrected QT intervals. Significant metabolic and electrolyte abnormalities at admission included hyperkalemia (potassium 6.5 mMol/L) and poorly compensated metabolic acidosis (pH 6.9, HCO3 5.1 mEq/L, PCO2 22 mm Hg, lactic acid 4.2 mMol/L, anion gap 24). During rewarming, the amplitude of the Osborn waves decreased progressively in relation to increasing body temperature, and they disappeared 24 hours later.

EKG at admission (Fig. 1):

Temperature: 83[degrees]F (28.3[degrees]C) rectal

Heart rate: 44 beats per minute 

PR: 340 milliseconds

QRS: 180 milliseconds

QTc: 583 milliseconds

[FIGURE 1 OMITTED]

EKG 50 minutes later (Fig. 2):

Temperature: 87[degrees]F (30.5[degrees]C) rectal

Heart rate: 55 beats per minute

PR: 200 milliseconds

QRS: 170 milliseconds

QTc: 490 milliseconds

EKG 24 hours later (Fig. 3):

Temperature: 98[degrees]F (36.6[degrees]C) rectal

Heart rate: 77 beats per minute

PR: 140 milliseconds

QRS: 65 milliseconds

QTc: 470 milliseconds

[FIGURE 2 OMITTED]

[FIGURE 3 OMITTED]

Discussion

The J-wave or Osborn wave (after Osborn's work into the mechanisms of this electrocardiographic change in the early 1950s (1)) is a prominent positive deflection in the terminal portion of the QRS complex. (2) It is caused by distortion of the earliest phase of membrane repolarization, causing a potential difference between the epicardium and endocardium during repolarization phases 1 and 2. (3) This transmural voltage gradient is manifested as a prominent J- or Osborn wave on the surface electrocardiogram.

Osborn waves usually occur in patients with core temperatures of less than 90[degrees]F (32[degrees]C) and their size generally correlates inversely with the body temperature. (2,4) Differential diagnoses of Osborn waves include hypothermia, hypercalcemia, early repolarization, and Brugada syndrome. (3,5-7)

Other electrocardiographic manifestations of hypothermia include sinus bradycardia, atrial and ventricular arrhythmias, prolonged intervals (PR, QRS, QT), different degrees of atrioventricular block, and findings related to electrolyte abnormalities (ie, hyperkalemia). (1,3,6,8)

Our case illustrates that sepsis-related hypothermia can manifest with the same electrocardiographic abnormalities as accidental hypothermia. Furthermore, rewarming is associated with proportional improvement of the initial Osborn waves and the conduction abnormalities.

References

1. Osborn JJ. Experimental hypothermia: respiratory and blood pH changes in relation to cardiac function. Am J Physiol 1953;175:389-398.

2. Gussak I, Bjerregaard P, Egan TM, et al. ECG phenomenon called the J wave: history, pathophysiology, and clinical significance. J Electrocardiol 1995;28:49-58.

3. Yan GX, Lankipalli RS, Burke JF, et al. Ventricular repolarization components on the electrocardiogram: cellular basis and clinical significance. J Am Coll Cardiol 2003;42:401-409.

4. Alsafwah S. Electrocardiographic changes in hypothermia. Heart Lung 2001;30:161-163.

5. Yan GX, Antzelevitch C. Cellular basis for the electrocardiographic J wave. Circulation 1996;93:372-379.

6. Mattu A, Brady WJ, Perron AD. Electrocardiographic manifestations of hypothermia. Am J Emerg Med 2002;20:314-326.

7. Kalla H, Yan GX, Marinchak R. Ventricular fibrillation in a patient with prominent J (Osborn) waves and ST segment elevation in the inferior electrocardiographic leads: a Brugada syndrome variant? J Cardiovasc Electrophysiol 2000;11:95-98.

8. Okada M. The cardiac rhythm in accidental hypothermia. J Electrocardiol 1984;17:123-128.

Gustavo A. Cardenas, MD, Hector O. Ventura, MD, and John E. Francis, MD

From the Department of Cardiology, Ochsner Clinic Foundation, New Orleans, LA.

Reprint requests to John E. Francis, MD, Section Head, Consultative Cardiology, Department of Cardiology, Ochsner Clinic Foundation, 1514 Jefferson Highway, New Orleans, LA 70121. Email: [e-mail]

Accepted January 26, 2006.

RELATED ARTICLE: Key Points

* Hypothermia causes asymmetric distortion of the earliest phase of membrane repolarization between the epicardium and endocardium, manifested as J-wave or Osborn wave.

* Sepsis-induced hypothermia can have similar electrocardiographic manifestations as accidental hypothermia.

* Differential diagnoses of Osborn waves include hypothermia, hypercalcemia, early repolarization and Brugada syndrome.

* Other electrocardiographic manifestations of hypothermia include supra- and ventricular arrhythmias as well as conduction abnormalities.