Familial case of permanent form of junctional reciprocating tachycardia: possible role of the HLA system.
The permanent form of junctional reciprocating tachycardia (PJRT) is a very rare arrhythmia with the following clinical and electrocardiographic findings: (1) it occurs predominantly in infants and children; (2) it is almost incessant and refractory to pharmacological therapy; (3) the onset is commonly related to a critical shortening of the P-P cycle length without P-R prolongation; (4) during tachycardia the ECG shows an R-P longer than P-R interval, with a negative P wave in leads II, III, aVF. Recently, the anatomic and electrophysiological characteristics underlying PJRT have been identified: there is an accessory pathway of working myocardium with decremental properties, located in the posterior pyramidal space. A case of familial PJRT is reported: the arrhythmia has been documented in a 72-year-old female and in her 16-year-old grandson. Several triggering tachycardia mechanisms have been observed. Tachycardia was almost incessant and the heart rates were 115 and 135 beats/min, respectively. Typing according to the HLA system, performed in all members of the family, demonstrated the Bw41 antigen in both our patients as well as in the boy's paternal uncle. This is the first documented familial case of PJRT, but the possible significance and correlation with the Bw41 antigen should be further investigated.