Biomed. Eng.-Biomed. Tech. 2015; 60(3): 245–255
Christopher Schilling, Matthias Keller, Daniel Scherr, Tobias Oesterlein, Michel Haïssaguerre, Claus Schmitt, Olaf Dössel and Armin Luik*
Fuzzy decision tree to classify complex fractionated atrial electrograms Abstract: Catheter ablation has emerged as an effective treatment strategy for atrial fibrillation (AF) in recent years. During AF, complex fractionated atrial electrograms (CFAE) can be recorded and are known to be a potential target for ablation. Automatic algorithms have been developed to simplify CFAE detection, but they are often based on a single descriptor or a set of descriptors in combination with sharp decision classifiers. However, these methods do not reflect the progressive transition between CFAE classes. The aim of this study was to develop an automatic classification algorithm, which combines the information of a complete set of descriptors and allows for progressive and transparent decisions. We designed a method to automatically analyze CFAE based on a set of descriptors representing various aspects, such as shape, amplitude and temporal characteristics. A fuzzy decision tree (FDT) was trained and evaluated on 429 predefined electrograms. CFAE were classified into four subgroups with a correct rate of 81±3%. Electrograms with continuous activity were detected with a correct rate of 100%. In addition, a percentage of certainty is given for each electrogram to enable a comprehensive and transparent decision. The proposed FDT is able to classify CFAE with respect to their progressive transition and may allow objective and reproducible CFAE interpretation for clinical use. Keywords: ablation; atrial electrograms; atrial fibrillation; CFAE; classification; fuzzy decision tree. DOI 10.1515/bmt-2014-0110 Received September 16, 2014; accepted February 6, 2015; online first March 12, 2015
*Corresponding author: Armin Luik, Städtisches Klinikum Karlsruhe, Karlsruhe, Germany, E-mail: [email protected] Christopher Schilling, Matthias Keller, Tobias Oesterlein and Olaf Dössel: Institute of Biomedical Engineering, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany Daniel Scherr and Michel Haïssaguerre : Hôpital Cardiologique du Haut-Lévêque, Bordeaux-Pessac, France Claus Schmitt: Städtisches Klinikum Karlsruhe, Karlsruhe, Germany
Introduction Atrial fibrillation (AF) is the most common cardiac arrhythmia, which affects morbidity and mortality [6]. AF is therefore a major and growing expense for health systems [11]. Catheter ablation has emerged as an effective treatment strategy in the last years. Since the discovery of foci inside the pulmonary veins (PVs) as a trigger for paroxysmal AF in 1998 [12], the technique of pulmonary vein isolation (PVI) has been established with acceptable success rates [29]. However, clinical outcome of PVI in persistent and long standing persistent AF is poor. This suggests different underlying mechanisms [4, 39, 40] outside the PV regions: multiple random propagating wavelets, focal electrical discharges or breakthroughs, and localized re-entrant activity with fibrillatory conduction [5]. However, differentiation during an electrophysiological (EP) study is limited as specific electrogram characteristics are not known. Ndrepepa et al. showed that persistent AF presents with shorter cycle lengths and more disorganized activity than paroxysmal AF [27]. Areas with complex fractionated atrial electrograms (CFAE) have been reported to potentially represent AF substrate sites [1, 24]. Nademanee defined CFAE as fractionated electrograms composed of two deflections or more, and/or as the perturbation of the baseline with continuous deflection of a prolonged activation complex and a median cycle length of
Christopher Schilling, Matthias Keller, Daniel Scherr, Tobias Oesterlein, Michel Haïssaguerre, Claus Schmitt, Olaf Dössel and Armin Luik*
Fuzzy decision tree to classify complex fractionated atrial electrograms Abstract: Catheter ablation has emerged as an effective treatment strategy for atrial fibrillation (AF) in recent years. During AF, complex fractionated atrial electrograms (CFAE) can be recorded and are known to be a potential target for ablation. Automatic algorithms have been developed to simplify CFAE detection, but they are often based on a single descriptor or a set of descriptors in combination with sharp decision classifiers. However, these methods do not reflect the progressive transition between CFAE classes. The aim of this study was to develop an automatic classification algorithm, which combines the information of a complete set of descriptors and allows for progressive and transparent decisions. We designed a method to automatically analyze CFAE based on a set of descriptors representing various aspects, such as shape, amplitude and temporal characteristics. A fuzzy decision tree (FDT) was trained and evaluated on 429 predefined electrograms. CFAE were classified into four subgroups with a correct rate of 81±3%. Electrograms with continuous activity were detected with a correct rate of 100%. In addition, a percentage of certainty is given for each electrogram to enable a comprehensive and transparent decision. The proposed FDT is able to classify CFAE with respect to their progressive transition and may allow objective and reproducible CFAE interpretation for clinical use. Keywords: ablation; atrial electrograms; atrial fibrillation; CFAE; classification; fuzzy decision tree. DOI 10.1515/bmt-2014-0110 Received September 16, 2014; accepted February 6, 2015; online first March 12, 2015
*Corresponding author: Armin Luik, Städtisches Klinikum Karlsruhe, Karlsruhe, Germany, E-mail: [email protected] Christopher Schilling, Matthias Keller, Tobias Oesterlein and Olaf Dössel: Institute of Biomedical Engineering, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany Daniel Scherr and Michel Haïssaguerre : Hôpital Cardiologique du Haut-Lévêque, Bordeaux-Pessac, France Claus Schmitt: Städtisches Klinikum Karlsruhe, Karlsruhe, Germany
Introduction Atrial fibrillation (AF) is the most common cardiac arrhythmia, which affects morbidity and mortality [6]. AF is therefore a major and growing expense for health systems [11]. Catheter ablation has emerged as an effective treatment strategy in the last years. Since the discovery of foci inside the pulmonary veins (PVs) as a trigger for paroxysmal AF in 1998 [12], the technique of pulmonary vein isolation (PVI) has been established with acceptable success rates [29]. However, clinical outcome of PVI in persistent and long standing persistent AF is poor. This suggests different underlying mechanisms [4, 39, 40] outside the PV regions: multiple random propagating wavelets, focal electrical discharges or breakthroughs, and localized re-entrant activity with fibrillatory conduction [5]. However, differentiation during an electrophysiological (EP) study is limited as specific electrogram characteristics are not known. Ndrepepa et al. showed that persistent AF presents with shorter cycle lengths and more disorganized activity than paroxysmal AF [27]. Areas with complex fractionated atrial electrograms (CFAE) have been reported to potentially represent AF substrate sites [1, 24]. Nademanee defined CFAE as fractionated electrograms composed of two deflections or more, and/or as the perturbation of the baseline with continuous deflection of a prolonged activation complex and a median cycle length of
