Ventricular arrhythmia

Ventricular arrhythmias are potentially very dangerous cardiacarrhythmias arising from the cardiac ventricles that require immediate attention and medical care and include the following rhythms:

• premature ventricular complexes
• ventricular tachycardia
• torsades de pointes
• ventricular flutter
• ventricular fibrillation

Ventricular tachyarrhythmias are those ventricular arrhythmias associated with an increased heart rate.

Epidemiology

The frequency of premature ventricular complexes is common and increases with age. Ventricular tachyarrythmias are commonly associated with ischaemic and structural heart disease ^1,2.

Associations

Ventricular arrhythmias are associated with the following conditions ^1-3:

• ischaemic heart disease
• structural heart disease
• cardiac arrest
• sudden cardiac death

Diagnosis

The diagnosis of ventricular arrhythmias is made on an electrocardiogram and can be classified into the following ^2-6:

• premature ventricular complexes
• ventricular tachycardia: wide QRS complexes (QRS ≥120 ms)
  • three or more consecutive beats with a heart rate of ≥100 bpm
  • sustained: >30 sec or with haemodynamic compromise
  • non-sustained: ≥3 beats with spontaneous termination
  • monomorphic ventricular tachycardia: stable QRS morphology
  • polymorphic ventricular tachycardia: multiform or alternating QRS morphology
  • bidirectional ventricular tachicardia
• torsades de pointes:
  • polymorphic ventricular tachycardia with long QT interval
  • waxing and waning QRS amplitude
• ventricular flutter: regular high heart rate ~250-300 bpm with a sinusoidal monomorphic appearance
• ventricular fibrillation: grossly irregular ventricular activity

Clinical presentation

Symptoms include fatigue, lightheadedness, dizziness, palpitations, presyncope, syncope and chest pain, dyspnoea ^1-3.

Complications

Complications of ventricular arrhythmias include ^2,3:

• heart failure
• cardiac arrest
• sudden cardiac death

Pathology

Mechanisms responsible for ventricular tachycardia include abnormal and/or increased automaticity, triggered activity and reentry ^2-4.

Aetiology

Aetiologies of ventricular tachycardia include ^2,3:

• myocardial ischaemia/myocardial infarction
• valvular heart disease
• cardiomyopathies
  • hypertrophic cardiomyopathy
  • arrhythmogenic right ventricular cardiomyopathy
  • infiltrative cardiomyopathies
  • left ventricular non-compaction
• channelopathies
  • long QT syndrome
  • short QT syndrome
  • Brugada syndrome
  • catecholaminergic polymorphic ventricular tachycardia
• drug toxicity
• metabolic disorders (hypokalaemia, hypomagnesaemia, hypocalcaemia)
• idiopathic

Treatment and prognosis

Management of ventricular arrhythmias depend on acute symptoms and the type of arrhythmia and include treatment of the underlying conditions and comorbidities, appropriate pharmacotherapy, device therapy and interventional therapy ^2,3.

Pharmacotherapy involves antiarrhythmic drugs such as beta-blockers, amiodarone, solatol and combination therapy ^2,3. Device therapy includes implantation of an implantable cardioverter defibrillator and interventional therapy includes catheter ablation and anti-arrhythmic surgery ^2,3.

Acute treatment of haemodynamically unstable patients includes cardioversion in case of or defibrillation depending on the respective ventricular arrhythmia according to advanced cardiac life support guidelines ^2,3.

Differential diagnosis

The differential diagnosis includes supraventricular tachycardia with or without bundle branch block ⁵.