Atrioventricular Conduction in Children With Acute Rheumatic Fever K. Sanyal, FAAP, FACC; Mohinder K. Thapar, MD, Dharm Bhushan Sharma, MD; Om Prabash Shrivastava, BSc

Shyamal

conduction was quantitatively evaluated in 118 children with acute rheumatic fever. The mean PR index in children with acute rheumatic fever, 1.06 \m=+-\0.38, was significantly higher than normal children or children who had febrile illness of nonrheumatic or \s=b\ Atrioventricular

nonstreptococcal origin (P < .001). Among 35 children with rheumatic fever and

an

abnormal PR index, the disease

presented as carditis in 21, arthritis in ten, and chorea in four. The mean PR index and the frequency distribution of abnormal PR indices were significantly higher in children with carditis (P < .001). Five children who initially had an abnormal PR index and arthritis or chorea subsequently developed carditis. These observations suggest that children with acute rheumatic fever and abnormal PR index warrant close observation for possible clinical evidence of myocardial involvement during subsequent course of the illness. (Am J Dis Child 130:473-476, 1976) Received for publication Jan 20, 1975; accepted June 11. From the Pediatric Cardiology Unit, Department of Pediatrics, Safdar Jung Hospital, New Delhi (Drs Thapar, Sharma, and Shrivastava), and St Jude Children's Research Hospital,

Memphis (Dr Sanyal).

Read in part before the annual meeting of the American Academy of Pediatrics, Washington, DC, 1975. Reprint requests to Pediatric Cardiology, St Jude Children's Research Hospital, PO Box 318, Memphis, TN 38101 (Dr Sanyal).

DCH;

Although delayed atrioventricular

XI (AV) conduction has been fre¬ quently reported in patients with acute rheumatic fever, the clinical and pathologic significance of this electro¬ cardiographic alteration remains con¬ troversial. While Clarke and Keith1 believe that these changes are rela¬ tively specific for acute rheumatic fever and that reversible PR prolon¬ gation should be used as a major diag¬ nostic criterion for acute rheumatic fever in patients with evidence of a preceding streptococcal infection, oth¬ ers maintain that prolongation of AV conduction in these patients is non¬

specific.-4 Thus, a comparative quan¬ titative study of AV conduction in children with major manifestations of

acute rheumatic fever seems war¬ ranted. Such a study presents certain prob¬ lems. Although the PR interval as measured by conventional electrocardiography has long been considered to represent AV conduction time,5 the variability in age and heart rate among children considerably in¬ fluences the duration of PR interval, and hence limits its usefulness. More¬ over, a delay in AV conduction may very well exist without the PR interval exceeding the upper limit of

normal.6-7 To overcome these limita¬ tions, Mirowski et al8 recently sug¬ gested a measurement of PR index that represents a ratio between the actual PR interval (numerator) and the upper limit of normal for the given age and heart rate (denomina¬ tor) as a better means for qualitative and quantitative evaluation of AV conduction. Accordingly, we designed a prospective study to determine the PR indices in children with various major manifestations of acute rheu¬ matic fever and to compare these values with those in normal children and children with acute febrile ill¬ nesses of nonrheumatic origin.

SUBJECTS AND METHODS

study

includes 187 children who Jung Hospital, New Delhi, over a period of four years (July 1967 to June 1971). This study population was divided into three groups. Group 1 consisted of 44 children who were completely normal on physical exami¬ nation and had no previous history of acute rheumatic fever. Group 2 consisted of 25 children who had developed fever from causes other than acute rheumatic fever or group A /3-hemolytic streptococcal infec¬ tion. Group 3 consisted of 118 children, 5 to 14 years of age, who fulfilled modified Jones criteria for acute rheumatic fever. This

were seen

at Safdar

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c

CD CO

CL

Acute Rheumatic

Febrile

Fever

Illnesses

Normal

of abnormal PR children with acute rheumatic fever, children with febrile illnesses, and normal controls.

Fig 1.—Percentage indices (>10) among

Carditis Fig 3.—Frequency distribution manifested

as

Arthritis

Chorea

of PR index in children with acute rheumatic fever either carditis, arthritis, or chorea.

Comparison of Mean PR Indices: Rheumatic Fever Subgroups vs Normal or Febrile Controls Rheumatic Fever

PR Index

Subgroups* 3A (arthritis) 3B (chorea)

(Mean ± SD)

3C

(carditis)

0.84 ±0.35 0.84 ± 0.35 1.01 ± 0.36

Normal Control (Mean ± SD)

Febrile Control

0.84 ±0.05

0.85 ±0.10

(Mean ± SD)

Of these subgroups only those children in whom acute rheumatic fever manifested as carditis had a PR index that was significantly higher than normal or febrile control values (P