Syndromes Causing PVCs or VT
The primary syndromes causing PVCs or VT include genetic arrhythmia syndromes (long QT syndrome, catecholaminergic polymorphic ventricular tachycardia, Brugada syndrome, short QT syndrome, and J wave syndromes), idiopathic ventricular arrhythmias (RVOT VT, idiopathic left ventricular tachycardia, and idiopathic propranolol-sensitive VT), and PVC-induced cardiomyopathy. 1, 2
Genetic Arrhythmia Syndromes (Ion Channelopathies)
These inherited conditions are critical to identify, particularly in young patients presenting with unexplained sudden cardiac arrest, near-drowning, or recurrent exertional syncope 1:
- Long QT Syndrome (LQTS): Presents with torsades de pointes; LQT1 variant particularly associated with drowning/near-drowning events 1
- Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT): Manifests as bidirectional VT, polymorphic VT, or catecholaminergic ventricular fibrillation; also linked to near-drowning episodes 1, 2
- Brugada Syndrome: Syncope and sudden death typically due to polymorphic VT 1, 2
- Short QT Syndrome: Less common but recognized cause of idiopathic polymorphic VT/VF 1
- J Wave Syndromes/Early Repolarization Syndrome: Associated with increased arrhythmic death risk from VF triggered by PVCs 1, 3
Genetic testing can provide a diagnosis in 13-60% of younger survivors of sudden cardiac arrest, making evaluation for these syndromes mandatory in patients under 40 years with unexplained events 1.
Idiopathic Ventricular Arrhythmias
These occur in the absence of structural heart disease and generally carry better prognosis 2:
- Right Ventricular Outflow Tract (RVOT) VT: Monomorphic VT, most common idiopathic form 2
- Idiopathic Left Ventricular Tachycardia (ILVT): Monomorphic, verapamil-sensitive 1, 2
- Idiopathic Propranolol-Sensitive VT (IPVT): May be monomorphic or polymorphic 2
These idiopathic forms are classified by ventricle of origin, pharmacologic response, catecholamine dependence, and morphologic features 2.
Idiopathic VF with Purkinje-Related PVCs
Idiopathic VF typically results from short-coupled PVCs arising from the Purkinje system in either ventricle or less commonly from ventricular myocardium 1. Key characteristics include:
- PVCs with consistent QRS morphology and short coupling interval
- Sharp initial QRS deflection and relatively narrow QRS duration suggesting Purkinje origin 4
- Very high recurrence risk (87% of patients experienced VF in preceding year before ablation) 1
- Can present as electrical storm with clusters of VF episodes 1
Multifocal Ectopic Purkinje-Related Premature Contractions (MEPPC)
A recently recognized syndrome presenting with multiform PVCs from Purkinje system, associated with SCN5A variants, can cause cardiomyopathy and respond to flecainide 4.
PVC-Induced Cardiomyopathy
When PVCs exceed 15% of total beats (predominantly of one morphology), they can cause reversible left ventricular dysfunction 1. This represents a distinct syndrome where suppression of PVCs improves ventricular function 5, 6.
Critical Clinical Pitfalls
- Do not dismiss PVCs in young patients with syncope, near-drowning, or exertional symptoms—these warrant genetic arrhythmia syndrome evaluation 1
- Family history of sudden cardiac death or cardiomyopathy significantly increases likelihood of inherited channelopathies 4
- PVC burden >15% warrants echocardiographic assessment for cardiomyopathy 1
- Subcutaneous ICDs may not be appropriate for idiopathic VF due to higher T-wave oversensing risk 1