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Published on: February 12, 2011
Rate of Change of Initial Intrinsicoid Deflection Predicts Endocardial Versus Epicardial Ventricular Tachycardia
Anthony R Prisco1, Justin Hayase2, Matthew Olson3
1Cardiology Division, University of Minnesota, Minneapolis, Minnesota, USA; Department of Surgery, Visible Heart Laboratories, University of Minnesota, Minneapolis, Minnesota, USA.
Insights
Epicardial ventricular tachycardia (VT) shows a slower initial depolarization rate compared to endocardial VT. This finding offers a new method for predicting the origin of VT using electrocardiography (ECG).
Area of Science:
- Cardiac Electrophysiology
- Cardiology
- Medical Diagnostics
Background:
- Distinguishing epicardial from endocardial origins of ventricular tachycardia (VT) is challenging due to limitations in current electrocardiographic (ECG) criteria and varying cardiomyopathy etiologies.
- Existing 12-lead ECG criteria for VT origin assessment exhibit inconsistent sensitivity and specificity depending on the VT source and underlying cardiomyopathy.
Purpose of the Study:
- To investigate the hypothesis that epicardial VT exhibits a slower initial rate of depolarization compared to endocardial VT.
- To develop and validate a novel ECG-based method for differentiating epicardial from endocardial VT origins.
Main Methods:
- A new technique was developed utilizing signal-averaged 12-lead ECG data to calculate the rate of change in initial VT depolarization.
- This method leverages the faster conduction velocity through the cardiac conduction system (primarily endocardial) versus the myocardium.
- The technique was applied to 26 patients with VT and nonischemic cardiomyopathy.
Main Results:
- Patients with epicardial VT demonstrated a significantly slower rate of depolarization (6.3 ± 3.1 mV/s) compared to those with endocardial VT (11.4 ± 3.7 mV/s; P < 0.05).
- Statistical significance was observed when analyzing all 12 ECG leads and limb leads, but not precordial leads.
- Receiver-operating characteristic curve analysis indicated strong predictive capability for epicardial origin (AUC range 0.72-0.88), with slower depolarization rates showing high sensitivity and specificity.
Conclusions:
- Depolarization rate analysis is a promising technique for predicting whether a ventricular tachycardia is epicardial in nature.
- This method offers a potential advancement in diagnosing VT origin, particularly in patients with challenging cardiomyopathy.
Background:
Assessment of origin of ventricular tachycardias (VTs) arising from epicardial vs endocardial sites are largely challenged by the available criteria and etiology of cardiomyopathy. Current electrocardiographic (ECG) criteria based on 12-lead ECG have varying sensitivity and specificity based on site of origin and etiology of cardiomyopathy.
Objectives:
This study sought to test the hypothesis that epicardial VT has a slower initial rate of depolarization than endocardial VT.
Methods:
We developed a method that takes advantage of the fact that electrical conduction is faster through the cardiac conduction system than the myocardium, and that the conduction system is primarily an endocardial structure. The technique calculated the rate of change in the initial VT depolarization from a signal-averaged 12-lead ECG. We hypothesized that the rate of change of depolarization in endocardial VT would be faster than epicardial. We assessed by applying this technique among 26 patients with VT in nonischemic cardiomyopathy patients.
Results:
When comparing patients with VTs ablated using epicardial and endocardial approaches, the rate of change of depolarization was found to be significantly slower in epicardial (6.3 ± 3.1 mV/s vs 11.4 ± 3.7 mV/s; P < 0.05). Statistical significance was found when averaging all 12 ECG leads and the limb leads, but not the precordial leads. Follow up analysis by calculation of a receiver-operating characteristic curve demonstrated that this analysis provides a strong prediction if a VT is epicardial in origin (AUC range 0.72-0.88). Slower rate of change of depolarization had high sensitivity and specificity for prediction of epicardial VT.
Conclusions:
This study demonstrates that depolarization rate analysis is a potential technique to predict if a VT is epicardial in nature.
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