Ventricular tachycardia as pirouette: causes, symptoms, diagnosis, treatment

Ventricular tachycardia of the "pirouette" type is a special form of polymorphic ventricular tachycardia in patients with an elongated interval. It is characterized by frequent, irregular complexes of QRS, which seem to "dance" around the contour on the electrocardiogram. This tachycardia can cease spontaneously or be transformed into ventricular fibrillation. It is accompanied by severe hemodynamic disorders and often death. Treatment includes intravenous administration of magnesium preparations, measures aimed at shortening the QT interval , and unsynchronized cardioversion when ventricular fibrillation develops.

The lengthening of the interval leading to the development of tachycardia as pirouette may be a congenital or induced medication.

Two identified hereditary PQ syndrome syndrome: Jervell-Lange-Nielsen syndrome (autosomal recessive inheritance pathway, associated with deafness) and Romano-Ward syndrome (autosomal dominant, without deafness). At the same time, at least six variants of the syndrome of the prolonged PQ interval are known, which result from a defect in genes encoding specific transmembrane potassium or sodium channels.

More often tachycardia like "pirouette" is the result of the use of drugs, usually antiarrhythmic drugs Ia, Ic, III classes. Other drugs include tricyclic antidepressants, phenothiazines, some antiviral and antifungal drugs.

Elongation of the interval leads to the development of arrhythmias due to the prolongation of repolarization, which induces early postdepolarization and a wide spread of refractory zones.

Symptoms of ventricular tachycardia as pirouette

Patients often complain about syncope, because the existing number of cuts (200-250 per minute) does not provide the necessary blood supply. Patients who are conscious, note the heartbeat. Sometimes the prolongation of the QT interval is diagnosed after restoring the rhythm.

Diagnosis of ventricular tachycardia as pirouette

The diagnosis is established according to the ECG data: the undulation-changing vertices of the QRS complexes, the complexes change their orientation around the isoline (Figures 75-18). An electrocardiogram between the seizures demonstrates an extended interval QT, corrected for heart rate (QT). Normal indices vary within 0.44 s, they differ markedly in different people and depending on sex. A family history may indicate a hereditary syndrome.

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Treatment of ventricular tachycardia as pirouette

Acute attack usually lasts long enough and causes hemodynamic disorders. It is eliminated by an unsynchronized cardioversion, starting with 100 J. However, as a rule, a repetition of the attack occurs quickly. Patients are often sensitive to magnesium preparations: magnesium sulfate in a dose of 2 g intravenously for 1-2 minutes. If this treatment is ineffective, a second bolus is given after 5-10 minutes. Patients who are not suffering from kidney failure, you can start infusion in a dose of 3-20 mg / min. Lidocaine (lb class) shortens the QT interval and can be effective mainly with a medicinal version of tachycardia of the type "pirouette", la, Ic and III classes of antiarrhythmic drugs are prohibited.

If the reason for the development of tachycardia as a "pirouette" are medicines, they should be discontinued, but patients with frequent or prolonged episodes of pirouette tachycardia should receive drugs shortening the QT interval before the end of the drug withdrawal . Since an increase in heart rate leads to a reduction in the PQ interval, temporary pacing, the introduction of isoproterenol intravenously, or a combination of these methods are often effective. Long-term therapy is necessary for patients with congenital syndrome of PQ interval prolongation. Treatment consists of the admission of b-adrenoblockers, constant pacemaking, ICDF, or a combination thereof. Family members should be examined with ECG.