What Does "Salvo" Mean on an EKG?
A "salvo" on an EKG refers to a brief run of 3 or more consecutive premature ventricular contractions (PVCs) occurring in rapid succession, also known as a triplet or short burst of non-sustained ventricular tachycardia (NSVT).
Definition and Classification
A salvo represents 3 or more consecutive PVCs that occur together but last less than 30 seconds, distinguishing it from sustained ventricular tachycardia 1, 2.
This pattern is also called a "triplet" when exactly 3 PVCs occur, or may be referred to as a short run of NSVT when more than 3 consecutive ventricular beats are present 1.
Salvos are more complex than isolated PVCs or couplets (2 consecutive PVCs), representing a higher grade of ventricular ectopy on the Lown classification system 2.
Clinical Significance and Risk Stratification
In patients with structural heart disease, particularly ischemic cardiomyopathy, the presence of salvos/NSVT carries increased risk for sustained ventricular tachycardia, ventricular fibrillation, and sudden cardiac death 1, 2.
In ischemic heart disease specifically, the frequency and complexity of PVCs (including salvos) is directly associated with mortality 2.
Salvos can trigger more dangerous arrhythmias, as electrocardiographic monitoring has revealed that frequent PVCs and salvos can initiate polymorphic ventricular tachycardia and ventricular fibrillation, particularly in patients with cardiomyopathy 3.
High burden ventricular ectopy including salvos can cause tachycardia-induced cardiomyopathy even in patients without preceding structural heart disease, which may be reversible with treatment 1, 2, 4.
Risk Assessment Algorithm
When salvos are detected, assess the following critical factors:
Presence of structural heart disease: Salvos in the setting of prior myocardial infarction, reduced left ventricular ejection fraction (LVEF ≤40%), or heart failure carry significantly higher risk 1, 2.
Frequency and burden: High PVC burden (>10,000-20,000 per 24 hours) with frequent salvos increases risk of PVC-induced cardiomyopathy 2, 4.
Symptom severity: Syncope, presyncope, palpitations with hemodynamic compromise, or cardiac arrest history indicate high-risk features requiring urgent evaluation 1.
LVEF and cardiac function: Reduced LVEF suggests either underlying cardiomyopathy or PVC-induced dysfunction 2, 4.
Management Approach
For patients with prior MI, LVEF ≤40%, and NSVT/salvos:
- Implantable cardioverter defibrillator (ICD) therapy is indicated if electrophysiological study demonstrates inducible ventricular fibrillation or sustained ventricular tachycardia 2.
For symptomatic patients or those with high PVC burden:
Beta-blockers and class III antiarrhythmic agents can be effective for medical suppression 1.
Radiofrequency ablation is the preferred definitive treatment in patients who improve with antiarrhythmic therapy, have tachycardia-induced cardiomyopathy, or have certain subtypes of PVCs/NSVT 1.
Ablation of trigger PVCs can eliminate salvos and improve left ventricular function, particularly when mapping reveals origins in scar border zones or specific anatomic locations 3, 4.
Critical Pitfalls to Avoid
Do not dismiss salvos as benign in patients with any degree of structural heart disease, as they represent a marker of increased arrhythmic risk and potential for sudden death 1, 2.
Do not overlook the possibility of PVC-induced cardiomyopathy when high-burden salvos are present with reduced LVEF, as this condition may be reversible with ablation or suppression 2, 4.
Recognize that salvos originating from unusual locations (aortic sinuses of Valsalva, great cardiac vein) may have variable coupling intervals and potentially higher arrhythmic risk 5.