Acquired complete heart block, in paediatric age is mainly the results of direct injury to conduction tissue during cardaic surgery or cardiac catheterisation. It can also be observed in different clinical settings as infectious diseases, neoplasia, and inflammatory diseases. It has a wide range of presentation and in some settings it can appear a dramatic event. Although a rare finding during acute rheumatic fever, with a transient course, it may need a specific and intensive treatment. We report a case of complete atrio-ventricular (AV) block in whom an Adams-Stokes attack was the first symptom of acute rheumatic carditis. We also reviewed the literature on complete atrio-ventricular block in acute rheumatic fever.

A 14-year-old Italian boy, weight 50 kg, was admitted to the emergency room of our Paediatric Department for syncope which occurred at home after he got out of bed. He had complained of transient thoracic pain the day before. On admission, the patient appeared extremely pale. Severe bradycardia (30 beats/minute) was found, blood pressure was 115/65 mmHg, respiratory rate 24/minute and transcutaneous oxygen saturation was 98%. A grade 2/6 systolic murmur was audible at the apex. The remaining physical examination was unremarkable.

The ECG showed a complete AV block with narrow QRS and a ventricular rate of 30 beats/minute (Figure 1). A 5.52 second period of asystole was recorded as well (Figure 2). Transthoracic echocardiography revealed mild mitral regurgitation, no cardiac chamber enlargement (left ventricle end-diastolic diameter was 47 mm) and normal contractility (ejection fraction 67%, shortening fraction 37%); a temporary pacemaker was implanted via the right femoral vein. In the suspicion of an inflammatory etiology, intravenous methyl-prednisolone (20 mg b.i.d) was started.

History pointed out a febrile pharyngitis occurred about one month before. At that moment, a rapid antigen detection test was positive for β-haemolytic group A Streptococcus. Amoxicillin plus clavulanate, 1 gram b.i.d, had been prescribed for ten days.

Laboratory investigations revealed neutrophilic leukocytosis (WBC 17.750/mm³, N 82%), elevation of ESR and CRP (72 mm/hr and 136 mg/L, respectively), elevated streptococcal antibodies (ASO titre 3.220 U/mL, streptozyme test positive 1/5000, anti-streptokinase antibodies positive 1/2560). The throat culture for β-haemolytic group A Streptococcus was negative. Myocardial necrosis indices and Borrelia Burgdorferi antibodies also were negative.

After 24 hours, the patient recovered sinus rhythm (HR = 80 beats/minute) with first degree AV block (PR duration 250 milliseconds). A second echocardiography confirmed the mild mitral regurgitation, but also showed a slight thickening of the aortic leaflets with trivial aortic regurgitation. The temporary pacemaker was removed and the anti-inflammatory treatment was continued with oral prednisone 25 mg b.i.d. for two weeks. When the normalisation of the inflammatory indices was achieved, steroid treatment was progressively tapered and acetylsalicylic acid 750 mg q.i.d. was started and continued for four weeks. ECG performed on fourth day after admission showed a normal sinus rhythm with a normal PR interval duration. Forty days after the first examination, echocardiography showed complete resolution of both mitral and aortic regurgitation; the Holter ECG showed a sinus rhythm with normal AV conduction.

The final diagnosis was Adams-Stokes attack due to complete AV block in the course of acute rheumatic carditis.

The most common cause of acquired complete AV block in the paediatric age group is direct injury to conduction tissue during cardiac surgery or cardiac catheterisation. In addition, complete atrio-ventricular block can be observed in infectious diseases as viral myocarditis, diphtheria, Lyme disease, in inflammatory illnesses such as acute rheumatic fever, metabolic diseases as Kearns-Sayre syndrome, drug toxicity (digoxin, beta-blockers, calcium-channel blockers), Chagas disease, tuberous sclerosis, intra-cardiac tumours, ischemia during coronary events or after mediastinal radiation.

The most common AV conduction abnormality found during acute rheumatic fever is first degree AV block, which was recognised in 72.5% of the Clarke’s series and in 72.3% of Zalzstein’s series (1, 2). Second degree AV block of Mobitz type I is much less frequent (2.6% in Clarke’s and 1.5% in Zalzstein’s series). Complete AV block was diagnosed in 0.6% of the Clarke’s and in 4.6% of Zalzstein’s series. Other types of rhythm abnormalities recognised during acute rheumatic fever include sinus node dysfunction, junctional rhythm and junctional tachycardia, ventricular tachycardia, torsade de pointes due to QT interval prolongation and complete left bundle branch block.

In Clarke’s series, only one of the three patients with complete AV block presented with an Adams-Stokes attack (1). All three patients with complete AV block of Zalzstein’s series were asymptomatic (2).

In our case, the Adams-Stokes attack was the first symptom of acute rheumatic fever. This occurred because of the high degree of complete AV block, with periods of asystole longer than five seconds.

We examined the literature in order to collect other cases of complete AV block due to rheumatic fever. We looked through PubMed’s MeSH vocabulary by inserting “rheumatic fever”, “atrio-ventricular block”, and “Adams-Stokes attack”.

We were able to find 19 full-text papers in which 25 cases of complete AV block due to rheumatic fever were reported [^1-19]. Ten of the 25 patients experienced an Adams-Stokes attack [¹,³,⁵,⁶,⁹,^11-15] (Table 1).

Nineteen of the 25 patients with complete AV block were certainly in the paediatric age group [¹,²,⁵,⁹,¹⁰,¹²,¹⁵,¹⁸,¹⁹]. Seven of the 19 experienced an Adams-Stokes attack [¹,⁵,⁶,⁹,¹²,¹⁵].

In 16 out of 25 cases, the duration of the AV block was reported: it lasted from a few minutes to ten days [¹,²,^4-8,¹⁰,¹⁵]; in one case, an ECG three months later showed persistence of the complete block [⁷]. Pacemaker implantation was necessary in seven cases.

Complete heart block during acute rheumatic fever is rare. Despite it can appear as a dramatic event, it is usually transient, resolving in few days after initiating anti-inflammatory treatment. Specific treatment, such as insertion of a temporary pacemaker, should be considered only when complete AV block leads to an Adams-Stokes attack. In our patient, the Adams-Stokes attack was the first symptom of rheumatic fever. Rheumatic fever must be kept in mind in the diagnostic work-up of patients with acquired complete AV block, particularly when it occurs in paediatric patients.

Written informed consent has been obtained from the parents of the patient for publication of this case report and any accompanying images.

ASO: Antibodies to streptolysin O; AV: Atrio – ventricular; CRP: C-reactive proteine; ECG: Electrocardigraphy; ESR: Erytrocyte sedimentation rate; WBC: White blood cells.

The authors declare that they have no competing interest.

NC: Data analysis, data interpretation and writing. IB: Literature search and writing. BT: Literature search, figures. EV: Data collection. SF: Data collection. AA: Writing. All authors read and approved the final manuscript.