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Heart failure in a man from Chile.

ECG of the Month

Presentation on page 180

DIAGNOSIS: Atrial fibrillation with a ventricular response of 104 beats/minute; Ashman's phenomenon; 1 RV6 > RV5 suggests left ventricular enlargement, (2) right axis deviation (106[degrees]) of the QRS complex with large S waves in leads V5 and V6 indicates right ventricular enlargement; (3) and large QRS voltage in the precordial leads compared to the limb leads implies a dilated cardiomyopathy. (4)

The refractory period after a ventricular complex ending a long R-R interval is longer than the refractory periods after complexes ending shorter R-R intervals. If the next ventricular depolarization is early, it usually finds the right bundle branch refractory, because it has the longest refractory period of any part of the conduction system. This is the basis of Ashman's phenomenon which is manifested in the 4th QRS from the end of the tracing where a QRS with right bundle branch block follows a short R-R interval that follows a long R-R interval. (1) Also best seen in lead [V.sub.1] is right bundle branch block in the second QRS, which follows a short R-R interval. We cannot see the preceding R-R interval, but it surely is long.

After diuresis an echo-Doppler study and cardiac catheterization confirm a dilated cardiomyopathy primarily involving the left-sided chambers, a left ventricular ejection fraction of 20% and moderate mitral and tricuspid regurgitation. Coronary arteriography shows normal arteries.

Although Chagas cardiomyopathy has some differences from so-called idiopathic dilated cardiomyopathy, (5) aside from direct or indirect evidence of prior Trypanosoma cruzi infection, (6) the two entities are more alike than different. Because most cases of Chagas cardiomyopathy in the U.S. are in immigrants or visitors from Latin America, (5,6) serologic testing for antibodies to T. cruzi is indicated for any Latin American patient with a dilated cardiomyopathy. Serologic testing in our patient is negative, and he has been treated as any other patient with idiopathic dilated cardiomyopathy.

REFERENCES

(1.) Ashman R, Byer E. Aberration in the conduction of premature ventricular impulses. J La State MedSoc 1946; 8:62-65.

(2.) Milliken JA, Macfarlane PW, Lawrie TDV. Enlargement and hypertrophy. In: Macfarlane PW, Lawrie TDV (editors). Comprehensive Electrocardiology: Theory and Practice in Health and Disease, Volume 1. New York: Pergamon Press; 1989:638.

(3.) ibid, 650-653.

(4.) Goldberger AL. A specific ECG triad associated with congestive heart failure. Pacing Clin Electrophysiol 1982; 5:593-599.

(5.) Pereira Nunes MC, Dones W, Morillo CA, et al. Chagas disease: an overview of clinical and epidemiological aspects. J Am Coll Cardiol 2013; 62:767-776.

(6.) Diaz JH. Chagas disease in the United States: a cause for concern in Louisiana? J La State Med Soc 2007; 159:21-29.

Dr. Glancy is an emeritus professor of medicine (cardiology) at the Louisiana State University Health Sciences Center in New Orleans, LA; Dr. Helmcke is an associate professor in the section of cardiology, department of medicine at the Louisiana State University Health Sciences Center in New Orleans, LA; Dr. Cochran was a cardiology fellow at the Louisiana Statue University Health Sciences Center in New Orleans, Louisiana and now practices in Mobile, AL.
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Title Annotation:ECG OF THE MONTH
Author:Glancy, D. Luke; Cochran, Glenn A.; Helmcke, Frederick R.
Publication:The Journal of the Louisiana State Medical Society
Article Type:Clinical report
Geographic Code:3CHIL
Date:Sep 1, 2016
Words:518
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