Baseline QRS morphology
Observed: Not assessed
Select an LBBB-like or RBBB-like pattern.
Loading EP-PVC Localizer AI…
12-Lead ECG Analysis
PVC Origin Localization
Enter the PVC morphology, frontal-plane axis, precordial transition, and optional advanced measurements to generate a preliminary localization estimate.
ECG Morphology Input
Select the ECG characteristics that best describe the clinical PVC morphology.
Select the first precordial lead where the R wave becomes greater than the S wave during the PVC.
Compare the sinus-rhythm transition with the PVC transition.
Select the predominant QRS polarity observed in lead I during the PVC.
Describe the overall PVC morphology in leads II, III, and aVF.
The V2 transition ratio calculator becomes available for an LBBB-like morphology with inferior axis and V3 transition.
Epicardial Feature Assessment
Maximum Deflection Index
Measure the interval from QRS onset to the maximum deflection in the precordial lead with the earliest maximum deflection, then divide it by the total PVC QRS duration.
Formula
MDI = time to maximum deflection ÷ total QRS duration
Enter two valid measurements. The deflection time cannot exceed the total QRS duration.
Required fields missing
- • Baseline QRS morphology
- • Frontal-plane axis
- • PVC precordial transition
Optional refinement
- • Sinus-rhythm transition is not selected.
- • Lead I polarity is not selected.
- • Inferior-lead morphology is not selected.
Explainability
Decision Trace
Review how each available ECG criterion contributed to the current regional estimate. A criterion can support a direction without being independently diagnostic.
Not assessed
Frontal-plane axis
Observed: Not assessed
Select the predominant limb-lead axis.
PVC precordial transition
Observed: Not assessed
Select the first lead with R greater than S.
Sinus/PVC transition relationship
Observed: Not assessed
The transition relationship is unavailable.
V2 transition ratio
Observed: Not applicable
This criterion is reserved for an LBBB-like, inferior-axis outflow-tract pattern with V3 transition.
Evidence: PMID 21616286
V2S/V3R index
Observed: Not applicable
This criterion was studied in LBBB-pattern, inferior-axis outflow-tract arrhythmias.
Evidence: PMID 24612087
Maximum deflection index
Observed: Not assessed
MDI measurements were not provided.
Evidence: PMID 16567566
Evidence References
The V2 transition ratio: a new electrocardiographic criterion for distinguishing left from right ventricular outflow tract tachycardia origin
Circulation: Arrhythmia and Electrophysiology · 2011 · PMID 21616286
Developed for outflow-tract ventricular arrhythmias with a V3 precordial transition. A ratio at or above 0.60 favored LVOT origin in the study population.
A novel electrocardiographic criterion for differentiating a left from right ventricular outflow tract tachycardia origin: the V2S/V3R index
Journal of Cardiovascular Electrophysiology · 2014 · PMID 24612087
DOI 10.1111/jce.12392
Studied in LBBB-pattern, inferior-axis outflow-tract arrhythmias. An index at or below 1.5 favored LVOT origin.
Idiopathic epicardial left ventricular tachycardia originating remote from the sinus of Valsalva
Circulation · 2006 · PMID 16567566
A maximum deflection index at or above 0.55 identified an epicardial-origin feature in the original study population.
Interpretation Boundary
Published ECG thresholds were derived in selected study populations. Their performance may change with structural heart disease, baseline conduction abnormalities, lead placement, measurement technique, and anatomical overlap.
Educational Testing
Example Case Library
Load an anonymous example to test the form and review how broad ECG patterns are processed. Examples are for software testing and education only.
Outflow-Tract Pattern
LBBB-like morphology, inferior axis, and V3 transition. Advanced outflow-tract indices can be added after loading.
Inferior Right-Ventricular Pattern
LBBB-like morphology with a superior axis, directing attention away from a typical superior outflow-tract pattern.
LV Fascicular/Papillary Pattern
RBBB-like morphology with a superior axis, prompting consideration of fascicular, papillary-muscle, or inferior LV sources.
Superior Left-Ventricular Pattern
RBBB-like morphology with an inferior axis, providing a broad superior-LV regional orientation.
Educational Limitation
These examples are simplified morphology combinations, not real patient records and not validated reference cases. Review the complete ECG and clinical context before any clinical use.
Case Workspace
Case Details and Local History
Add a case name and optional clinical note. Saved cases remain in this browser only and are not uploaded to a server.
Recent Local Cases
No locally saved cases.
Privacy Note
Do not enter names, identification numbers, dates of birth, or other direct patient identifiers. Local browser storage is not a substitute for an approved clinical record system.