Shortening of the PQ interval

In our article we have collected information about the medical term, often encountered in the evaluation of a cardiogram - this is a shortening of the PQ interval.

Decoding and interpretation of ECG results is a question that should be addressed to a cardiologist. 

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Causes of shortening of the PQ interval

These changes in cardiographic indications are a symptom of the formation of indirect conduction pathways and can cause paroxysmal supraventricular tachycardia (one of the types of arrhythmia). However, such a symptom may not be a pathology, but merely an asymptomatic ECG sign.

A shortened interval in the absence of any symptomatology can act as one of the variants of the norm, or as a result of an increased sympathetic tone. Such manifestations are not dangerous and should not disturb the patient.

An extended PQ interval may be observed with a vagal effect, with sedatives or beta blockers, which can confirm the functional reason for the short PQ interval.

The pathological nature of the shortening of this interval can be detected at the lower atrial or AB-nodal rhythm, or with early ventricular excitation. This situation can be distinguished by considering the tooth P.

In some patients, the short PQ interval is not associated with the emergence of an indirect path, but with a short impulse movement along the AB-node. This situation can be observed in people who have had myocardial infarction: they also have periods of ventricular arrhythmia.

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Syndrome shortening of the interval PQ

This syndrome was scientifically described back in 1938, when scientists analyzed two hundred of similar cardiograms. Interestingly, most patients with this syndrome did not have any cardiac pathology. Only 11% had diagnoses of paroxysms of supraventricular tachycardia. A short interval of PQ is a form of arrhythmia.

The term "pre-excitation of the ventricles" suggests the corresponding signs of ECG in the absence of arrhythmia, and the syndrome of ventricular pre-excitation is a combination of ECG-signs with paroxysmal tachycardia. It follows that the phenomenon of shortening the PQ interval is the detection on the ECG of the PQ-interval with an index less than 120 ms (0.12 s) in an adult patient and less than the children's age norm (provided there is no arrhythmia). The same short PQ interval is a combination of ECG signs with paroxysmal supraventricular tachycardia.

The shortening of the PQ interval in adults is an interval value of less than 0.12 s. It speaks of too rapid passage of a pulse from the atrium to the ventricles. Whether this sign is an indicator of premature ventricular excitation, which is considered a conduction disorder and refers to a particular type of arrhythmia, the specialist decides.

The shortening of the PQ interval in children depends on the child's age and is often observed in infants, less often in adolescence. Perhaps this is due to the age-specific features of the duration of the interval and the anatomical alteration of the AB node. For today, PQ interval length indices are used in practice depending on the age of the child, but the variety of data from different authors makes it difficult to diagnose a shortened interval in pediatrics. These criteria require significant improvement and refinement, with the definition of clear values of the interval according to age and frequency inherent in the main rhythm.

Symptoms of shortening of the PQ interval

If the appearance on the ECG of a short interval is not related to asymptomatic flow and is considered a deviation from the norm, it is possible to observe in the patient the signs of periodic paroxysmal paroxysmal tachycardia, a rapid heartbeat that lasts several seconds (10-20 seconds) and passes more often independently and without consequences. Such seizures can occur at different times, sometimes they are associated with a stressful situation, but often the cause remains unclear.

Spontaneous tachycardia can be accompanied by a feeling of discomfort behind the sternum, panic fear, pallor of the skin, the appearance of sweat on the face.

Unpleasant sensations are not always present, often the patient does not even suspect that he has a cardiac pathology.

The shortening of the PQ interval on the ECG is measured from the initial point of the P wave to the initial point of the tooth Q: the usually frequent rhythm and short interval are interrelated. The norm indicators are usually from 120 to 200 ms.

Treatment of shortening of the PQ interval

Shortening of PQ against the background of a normal rhythm of contractions of the heart and the absence of clinical cardiological symptoms in treatment does not need. The presence of any pathology of the heart, arrhythmia, paroxysmal tachycardia, myocarditis, heart attack requires a deeper cardiological examination and the appointment of appropriate treatment.

Modern medicine offers a catheter technique for the therapy of many variants of tachycardias, including with a reduction in the PQ interval. The use of radiofrequency catheter ablation and cryoablation is performed depending on the nature of the specific arrhythmia.

Of course, you need to treat the root cause of this condition. And the cause will be determined only by a specialist based not only on the ECG, but also on all possible additional methods of investigation.

Preventing shortening of the PQ interval

If even with the resulting ECG shortening of the PQ interval, tachycardia attacks never bothered you, then the possibility of their occurrence in the future is very small. This condition is not dangerous and no therapeutic and preventive measures are required.

If the clinical picture of cardiac pathologies is obvious, then, first of all, you should consult a doctor and follow-up.

Among the general methods for the prevention of heart disease, we can distinguish the following:

• active lifestyle, moderate physical activity;
• fighting overweight;
• high-grade high-quality food;
• a clear refusal to smoke and drink alcohol;
• limiting the amount of salt used;
• full rest, good sleep.

Try to avoid stressful situations, do not worry for no reason, take care of your nerves and do not stumble on others. Travel more, communicate with friends, with family, rejoice at every moment of life.

PQ shortening forecast

In patients with shortening of the PQ interval with asymptomatic flow, the prognosis is positive, since the possibility of the appearance of rapid impulse transmission along an indirect path is rather small.

The exception can be made by patients with burdened heredity by the type of sudden deaths among direct relatives. Of the exceptions, we can also refer to professional athletes and test pilots.

In patients with complaints of paroxysmal tachycardia, the risk of complications is much higher. The use of antiarrhythmic therapy and radiofrequency ablation in their case significantly improves the prognosis of the disease.

If you have found a shortening of the PQ interval, do not make hasty conclusions: consultation of a cardiologist is mandatory, and only a specialist can accurately tell all information about your condition. And to experience in advance it is not necessary - probably, to it there are no reasons.