Lesson topic №25. Нарушения ритма (Cardiac arrhythmia in the outpatient setting)

Cardiac arrhythmia in the outpatient setting

Gerasimenko I.A. Department of polyclinic therapy with course of general medical practice (family medicine)

Cardiac arrhythmia

A cardiac arrhythmia simply defined is a variation from the normal heart rate and/or rhythm that is not physiologically justified.

Atrial premature beats

Atrial premature beats

Atrial premature beats (APBs), also referred to as atrial or supraventricular extrasystoles, represent premature atrial depolarization occurring earlier than the next expected regular sinoatrial activation, usually from a site outside the sinus node.

Premature depolarizations originating from the atrioventricular node or His bundle are termed atrioventricular junctional premature beats.

Atrial premature beats

In general, APBs occur in adults of any age, with or without structural heart disease.

Increased atrial volume and/or pressure, or increased sympathetic tone are associated with increased frequency of APBs, while in individuals without structural heart disease APBs often originate from the pulmonary veins and may precipitate atrial fibrillation.

Patients with APBs are often asymptomatic, or experience palpitations, dizziness.

Physical examination may reveal pulse irregularity, and surface electrocardiograms (ECGs) usually show premature P waves which differ from the sinus P morphology, followed by a normal, shortened, or prolonged PR interval (depending on the APB site of origin) and narrow QRS complex.

Ambulatory ECG (Holter) monitoring helps to establish the diagnosis when symptoms are sporadic or to quantify the frequency of APBs.

Atrial premature beats

Counselling and reassurance would suffice in most minimally symptomatic or asymptomatic patients with APBs, but any underlying cardiovascular disorder must be treated.

Beta blockers or class III antiarrhythmic drugs (or class IC in patients without significant structural heart disease) can be used to attenuate symptoms or suppress the APBs facilitating other tachyarrhythmias.

Catheter ablation could be considered in selected patients.

Supraventricular tachycardia

Supraventricular tachycardia

The term ‘SVT’ literally indicates tachycardia [atrial rates >100 beats per minute (b.p.m.) at rest], the mechanism of which involves tissue from the His bundle or above.

Traditionally, SVT has been used to describe all kinds of tachycardias apart from ventricular tachycardias (VTs) and AF.

Supraventricular tachycardia: classification

AV junctional tachycardias

Atrioventricular nodal re-entrant tachycardia (AVNRT)

•Typical

•Atypical

Non-re-entrant junctional tachycardia

•JET (junctional ectopic or focal junctional tachycardia)

•Other non-re-entrant variants

Atrioventricular re-entrant tachycardia (AVRT)

•Orthodromic (including PJRT)

•Antidromic (with retrograde conduction through the AVN or, rarely, over another pathway)