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Body Surface Mapping of T-wave Alternans Depends on the Distribution of Myocardial Scarring.

Zeller A, Ghoraani B - Open Cardiovasc Med J (2015)

Bottom Line: Cardiac scarring with different sizes were simulated by manipulating the apparent velocity, transmembrane potential and transition zone at varied locations along the left ventricular posterior wall.The TWA amplitude generally increased with the increment of scar size (P<0.00001).We found one specific location (a non-standard lead) that consistently appeared as the top five maximum TWA leads and could be considered as an additional lead to improve the outcome of the TWA testing in cardiomyopathy patients.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, Rochester Institute of Technology, Rochester, NY, USA.

ABSTRACT
T-Wave alternans (TWA) testing using 12-lead electrocardiogram/Frank leads is emerging as an important non-invasive biomarker to identify patients at high risk of Sudden Cardiac Death (SCD). Cardiac scarring is very common among cardiomyopathy patients; however, its influence on the body surface distribution of TWA has not yet been defined. Our objective was to perform a simulation study in order to determine whether cardiac scarring affects the distribution of TWA on thorax such that the standard leads fail to detect TWA in some of cardiomyopathy patients; thereby producing a false-negative test. Developing such a novel lead configuration could improve TWA quantification and potentially optimize electrocardiogram (ECG) lead configuration and risk stratification of SCD in cardiomyopathy patients. The simulation was performed in a 1500-node heart model using ECGSIM. TWA was mimicked by simulating action potential duration alternans in the ventricles. Cardiac scarring with different sizes were simulated by manipulating the apparent velocity, transmembrane potential and transition zone at varied locations along the left ventricular posterior wall. Our simulation study showed that the location of maximum TWA depends on the location and size of the myocardium scarring in patients with cardiomyopathy, which can give rise to false-negative TWA signal detection using standard clinical leads. The TWA amplitude generally increased with the increment of scar size (P<0.00001). We found one specific location (a non-standard lead) that consistently appeared as the top five maximum TWA leads and could be considered as an additional lead to improve the outcome of the TWA testing in cardiomyopathy patients.

No MeSH data available.


Related in: MedlinePlus

Two consecutive ECG signals are denoted as even and odd beats. The T wave alternates in shape from the even beat to the odd beat. The microvolt change in the amplitude or shape of the T waves between the beats is a TWA.
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Figure 2: Two consecutive ECG signals are denoted as even and odd beats. The T wave alternates in shape from the even beat to the odd beat. The microvolt change in the amplitude or shape of the T waves between the beats is a TWA.

Mentions: TWA is defined as the alternation in either the amplitude or shape of the T wave in the every other beat of the ECG (see Fig. 2). In this diagram, TWA is measured as the difference between 2 consecutive beats that are labeled as either an even or an odd beat. As described in clinical medicine a TWA of greater than 1.9 microvolts is used to identify a high-risk patient [16]. TWA were simulated using ECGSIM by manipulating APDA and then calculated using MATLAB.


Body Surface Mapping of T-wave Alternans Depends on the Distribution of Myocardial Scarring.

Zeller A, Ghoraani B - Open Cardiovasc Med J (2015)

Two consecutive ECG signals are denoted as even and odd beats. The T wave alternates in shape from the even beat to the odd beat. The microvolt change in the amplitude or shape of the T waves between the beats is a TWA.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4378024&req=5

Figure 2: Two consecutive ECG signals are denoted as even and odd beats. The T wave alternates in shape from the even beat to the odd beat. The microvolt change in the amplitude or shape of the T waves between the beats is a TWA.
Mentions: TWA is defined as the alternation in either the amplitude or shape of the T wave in the every other beat of the ECG (see Fig. 2). In this diagram, TWA is measured as the difference between 2 consecutive beats that are labeled as either an even or an odd beat. As described in clinical medicine a TWA of greater than 1.9 microvolts is used to identify a high-risk patient [16]. TWA were simulated using ECGSIM by manipulating APDA and then calculated using MATLAB.

Bottom Line: Cardiac scarring with different sizes were simulated by manipulating the apparent velocity, transmembrane potential and transition zone at varied locations along the left ventricular posterior wall.The TWA amplitude generally increased with the increment of scar size (P<0.00001).We found one specific location (a non-standard lead) that consistently appeared as the top five maximum TWA leads and could be considered as an additional lead to improve the outcome of the TWA testing in cardiomyopathy patients.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, Rochester Institute of Technology, Rochester, NY, USA.

ABSTRACT
T-Wave alternans (TWA) testing using 12-lead electrocardiogram/Frank leads is emerging as an important non-invasive biomarker to identify patients at high risk of Sudden Cardiac Death (SCD). Cardiac scarring is very common among cardiomyopathy patients; however, its influence on the body surface distribution of TWA has not yet been defined. Our objective was to perform a simulation study in order to determine whether cardiac scarring affects the distribution of TWA on thorax such that the standard leads fail to detect TWA in some of cardiomyopathy patients; thereby producing a false-negative test. Developing such a novel lead configuration could improve TWA quantification and potentially optimize electrocardiogram (ECG) lead configuration and risk stratification of SCD in cardiomyopathy patients. The simulation was performed in a 1500-node heart model using ECGSIM. TWA was mimicked by simulating action potential duration alternans in the ventricles. Cardiac scarring with different sizes were simulated by manipulating the apparent velocity, transmembrane potential and transition zone at varied locations along the left ventricular posterior wall. Our simulation study showed that the location of maximum TWA depends on the location and size of the myocardium scarring in patients with cardiomyopathy, which can give rise to false-negative TWA signal detection using standard clinical leads. The TWA amplitude generally increased with the increment of scar size (P<0.00001). We found one specific location (a non-standard lead) that consistently appeared as the top five maximum TWA leads and could be considered as an additional lead to improve the outcome of the TWA testing in cardiomyopathy patients.

No MeSH data available.


Related in: MedlinePlus