Permanent junctional reciprocating tachycardia (PJRT) is a rare

cardiac arrhythmia Arrhythmias, also known as cardiac arrhythmias, are irregularities in the heartbeat, including when it is too fast or too slow. Essentially, this is anything but normal sinus rhythm. A resting heart rate that is too fast – above 100 beat ...

. It is a

supraventricular tachycardia Supraventricular tachycardia (SVT) is an umbrella term for fast heart rhythms arising from the upper part of the heart. This is in contrast to the other group of fast heart rhythms – ventricular tachycardia, which start within the lower cham ...

, and a cause of atrioventricular reentrant tachycardia (AVRT). PJRT can cause chronic

tachycardia Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. Heart rates above the resting rate may be normal ...

that, untreated, leads to

cardiomyopathy Cardiomyopathy is a group of primary diseases of the heart muscle. Early on there may be few or no symptoms. As the disease worsens, shortness of breath, feeling tired, and swelling of the legs may occur, due to the onset of heart failure. A ...

. The cause is an

accessory pathway In cardiology, an accessory pathway is an additional electrical connection between two parts of the heart. These pathways can lead to abnormal heart rhythms ( arrhythmias) associated with symptoms of palpitations. Some pathways may activate a regi ...

in the heart which conducts from the ventricles back to the

atria Atria may refer to: Science *Atrium (heart) (plural: atria), an anatomical structure of the heart *Atria (genus), a flatworm genus in the family Dendrocoelidae * Atria (star) or Alpha Trianguli Australis, a star in the constellation Triangulum Aus ...

. Unlike the accessory pathway in a more common cause of AVRT,

Wolff–Parkinson–White syndrome Wolff–Parkinson–White syndrome (WPWS) is a disorder due to a specific type of problem with the electrical system of the heart involving an accessory pathway able to conduct electrical current between the atria and the ventricles, thus byp ...

, the accessory pathway in PJRT conducts slowly. This means that the associated tachycardia may be

subclinical Asymptomatic (or clinically silent) is an adjective categorising the medical conditions (i.e., injuries or diseases) that patients carry but without experiencing their symptoms, despite an explicit diagnosis (e.g., a positive medical test). P ...

and only diagnosed at a late stage, after significant damage to the heart has been caused from prolonged and recurrent episodes of AVRT.Tanner H. ''Permanent junctional reciprocating tachycardia''. ESC CardioMed (3 edn). Oxford University Press. . Dec 2018

/ref> While PJRT generally presents itself in infants, and often immediately after birth, few adults can suffer from a sudden onset of PJRT in which the degrading accessory pathway can more often than not be in a non-posteroseptal site.

Symptoms

Palpitations Palpitations occur when a person becomes aware of their heartbeat. The heartbeat may feel hard, fast, or uneven in their chest. Symptoms include a very fast or irregular heartbeat. Palpitations are a sensory symptom. They are often described as ...

during exercise or stress may be the presenting symptom. Because the initial symptoms are often mild, there may be significant

myocardial Cardiac muscle (also called heart muscle or myocardium) is one of three types of vertebrate muscle tissues, the others being skeletal muscle and smooth muscle. It is an involuntary, striated muscle that constitutes the main tissue of the wall of ...

damage at the time of diagnosis. It is therefore possible for these patients to present with the symptoms of

heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome caused by an impairment in the heart's ability to Cardiac cycle, fill with and pump blood. Although symptoms vary based on which side of the heart is affected, HF ...

, such as shortness of breath, fatigue and oedema (fluid retention).

Cause

In-between episodes there is normal electrical conduction in the heart. During an episode of AVRT caused by PJRT, the accessory pathway conducts electrical activity from the ventricles directly back to the atria at the end of

systole Systole ( ) is the part of the cardiac cycle during which some chambers of the heart contract after refilling with blood. Its contrasting phase is diastole, the relaxed phase of the cardiac cycle when the chambers of the heart are refilling ...

, which triggers the atria to contract, and the current to pass back to the ventricles again via the atrioventricular node (AV node); see diagram.

Diagnosis

There may be no signs outside of an episode. An electrocardiogram (ECG) undertaken during an episode of AVRT demonstrates typical features of ''retrograde'' (inverted) p-waves in the inferior leads II, III, aVF, and V4–V6 with a long RP′ interval. The P:QRS ratio would be 1:1 and they would be narrow complexes.

Treatment

Termination of an episode of AVRT in PJRT can be achieved with vagal manouvres,

antiarrhythmic Antiarrhythmic agents, also known as cardiac dysrhythmia medications, are a class of drugs that are used to suppress abnormally fast rhythms (tachycardias), such as atrial fibrillation, supraventricular tachycardia and ventricular tachycardia. M ...

medications or

DC cardioversion Cardioversion is a medical procedure by which an abnormally fast heart rate (tachycardia) or other cardiac arrhythmia is converted to a sinus rhythm, normal rhythm using electricity or pharmaceutical drug, drugs. Synchronized electrical cardiov ...

. Long-term management is best achieved with

catheter ablation Catheter ablation is a procedure that uses radio-frequency energy or other sources to terminate or modify a faulty electrical pathway from sections of the heart of those who are prone to developing cardiac arrhythmias such as atrial fibrillation ...

Prognosis

Without treatment, the prevalence of tachycardia-induced cardiomyopathy has been reported to be between 20% and 50%, however most patients who undergo ablation have significant improvement in their cardiac function Bensler, James Michael et al. “Tachycardia-mediated cardiomyopathy and the permanent form of junctional reciprocating tachycardia.” Texas Heart Institute journal vol. 37,6 (2010): 695-8.

References

{{Circulatory system pathology Cardiac arrhythmia