Enhancing electrocardiographic analysis by combining a high-resolution 12-lead ECG with novel software tools.

INTRODUCTION: Signal-averaged electrocardiography is a non-invasive, computerized technique that amplifies, filters, and averages cardiac electrical signals reducing contaminating noise to obtain a high-resolution record. The most widely used signal averaging (SA) method involves a bipolar X, Y, and Z orthogonal lead system. Information is limited regarding its application in the standard resting 12-lead ECG. A novel system combining a high-resolution 12-lead ECG (HR-ECG) registered by SA with advanced analysis tools is presented. HISTORY: Original programming of a commercially available signal-averaged HR-ECG device was modified, introducing more exhaustive electrocardiographic assessment instruments. DESCRIPTION: Using SA techniques and placing surface electrodes in the standard 12-lead ECG positions, a HR-ECG is acquired within a bandwidth of 0.25 to 262 Hz at a rate of 1000 samples per second. It is advisable to average at least 200 cycles, taking three to five minutes to record. The package includes different optional high-frequency filters, manual calipers, zoom/superimposing/amplification functions. CLINICAL ROLE: The main strength lies in obtaining a low noise HR-ECG with zooming capabilities without definition loss. Other potential advantages are the greater ease in performing high precision analysis and comparing different ECG leads simultaneously. CURRENT PROBLEMS: The primary limitation is the inability to document intermittent or dynamic electrocardiographic disorders because of averaging similar electrical cardiac cycles. FUTURE DEVELOPMENTS: Adding artificial intelligence and further refinements in the averaging process could lead to software upgrades. CONCLUSION: Integrating HR-ECG, obtained through SA techniques, with novel advanced analysis tools can enhance the ability to detect electrocardiographic disorders of permanent expression expeditiously.

Epsilon Wave Masked by ST-Segment Elevation After Cardioversion From Sustained Ventricular Tachycardia: An Exceptional Manifestation of Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy.

BACKGROUND: Early recognition and management of ventricular dysrhythmia (VD) are among the top priorities in the medical field, and are very important in cases of suspected acute coronary syndrome (ACS). Here we present a case of ventricular tachycardia (VT), which should be considered in ACS. CASE REPORT: A 59-year-old man with unstable vital signs visited the emergency department (ED) after a syncopal episode associated with chest discomfort. Initial electrocardiography (ECG) revealed wide complex tachycardia, which was considered monomorphic VT. After successful cardioversion, ST-segment elevation was observed on subsequent ECG with reciprocal ST-segment depression. Immediate pharmacological treatment and coronary angiography were performed because of suspected acute myocardial infarction; however, normal coronary arteries were observed. On subsequent ECG analysis, a small blip at the end of the QRS complex termed an epsilon wave, which is a characteristic finding in arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C), was detected in the V1 lead. A borderline diagnosis of ARVD/C was made based solely on ECG findings, and the definite diagnosis was confirmed using echocardiography. An implantable cardioverter-defibrillator was inserted soon after, and the patient reported no further events. Why Should an Emergency Physician be Aware of This?: ARVD/C is a critical disease entity that is commonly associated with life-threatening VA. However, presentations of ARVD/C resembling ACS are exceptionally rare. Accordingly, accurate diagnosis of ARVD/C in ED settings is clinically challenging. A high clinical suspicion is required to identify ARVD/C and avoid further life-threatening episodes.

Epsilon wave: A review of historical aspects.

The epsilon wave of the electrocardiogram (ECG) together with fragmented QRS (fQRS), the terminal conduction delay, incomplete right bundle branch block (IRBBB) and complete/advanced RBBB (CRBBB) of peripheral origin are part of a spectrum of ventricular depolarization abnormalities of arrhythmogenic cardiomyopathy(AC). Although the epsilon wave is considered a major diagnostic criterion for AC since 2010 (AC Task Force Criteria), its diagnostic value is limited because it is a sign of the later stage of the disease. It would be more appropriate to say that the epsilon wave is a "hallmark" of AC, but is of low diagnostic sensitivity. Although the epsilon wave has high specificity for AC, it can be present in other pathological conditions. In this update we will cover the nomenclature, association with disease states and electrocardiographic aspects of the epsilon wave.

Epsilon wave on an electronic loop in a case of arrhythmogenic right ventricular dysplasia with myocarditis: an updated definition of the Epsilon wave.

A young man presented with a history of myocarditis with palpitations and dizziness. He had implantation of a loop recorder that showed repetitive short episodes of VT. In addition, there were fragmented potentials immediately following the large and sharp electrograms (EGMs) before as well as after episodes of VT suggesting an Epsilon wave. This signal can be observed in multiple cardiac conditions including coronary artery disease. It was originally recorded on the epicardium as well as on the endocardium. However, in ARVD it can be defined as an electric signal observed after the end of the QRS complex in the right as opposed to the left precordial leads (difference ≥ 25 ms). It can also be an aid to the diagnosis of patients with ARVD who have other signs or symptoms suggesting ARVD including episodes of myocarditis. This potential consists of a slurring at the end of the QRS complex or an independent potential after the return to the isoelectric line. It can be better observed by increasing amplification of the ECG tracing as well as double speed using the Fontaine lead system. Epsilon wave too small to be recorded on the standard ECG can be extracted by Signal Averaging ECG SAECG).

Electroanatomic Correlates of Depolarization Abnormalities in Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy.

BACKGROUND: Epsilon waves and other depolarization abnormalities in the right precordial leads are thought to represent delayed activation of the right ventricular outflow tract in arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). However, no study has directly correlated cardiac electrical activation with the surface ECG findings in ARVD/C. METHODS AND RESULTS: Thirty ARVD/C patients (mean age 32.7 ± 11.2 years, 16 men) underwent endocardial and epicardial electroanatomical activation mapping in sinus rhythm. Twelve-lead ECGs were classified into 5 patterns: (1) normal QRS (11 patients); (2) terminal activation delay (TAD) (3 patients); (3) incomplete right bundle branch block (IRBBB) (5 patients); (4) epsilon wave (5 patients); (5) complete right bundle branch block (CRBBB) (6 patients). Timing of local ventricular activation and extent of scar was then correlated with surface QRS. Earliest endocardial and epicardial RV activation occurred on the mid anteroseptal wall in all patients despite the CRBBB pattern on ECG. Total RV activation times increased from normal QRS to prolonged TAD, IRBBB, epsilon wave, and CRBBB, respectively (103.9 ± 5.6, 116.3 ± 6.5, 117.8 ± 2.7, 146.4 ± 16.3, and 154.3 ± 6.3, respectively, P < 0.05). The total epicardial scar area (cm(2) ) was similar among the different ECG patterns. Median endocardial scar burden was significantly higher in patients with epsilon waves even compared with patients with CRBBB (34.3 vs. 11.3 cm(2) , P < 0.01). Timing of epsilon wave corresponded to activation of the subtricuspid region in all patients. CONCLUSION: We found that epsilon waves are often associated with severe conduction delay and extensive endocardial scarring in addition to epicardial disease. The timing of epsilon waves on surface ECG correlated with electrical activation of the sub-tricuspid region.

Biventricular Arrhythmogenic Cardiomyopathy Mimicking Cardiac Sarcoidosis.

Noninvasive imaging is crucial for diagnosing and managing arrhythmogenic cardiomyopathy. Despite advanced multimodality imaging tools, challenges persist in differentiating it from other arrhythmogenic diseases (eg, cardiac sarcoidosis). We present a case of arrhythmogenic cardiomyopathy with an FLNC variant of uncertain significance exhibiting a phenocopy of cardiac sarcoidosis.

Correlation between Epsilon Wave and Late Potentials in Arrhythmogenic Right Ventricular Cardiomyopathy-Do Late Potentials Define the Epsilon Wave?

Introduction: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetic disorder characterised by progressive fibrosis predominantly of the right ventricular (RV) myocardium, resulting in life-threatening arrhythmias and heart failure. The diagnosis is challenging due to a wide spectrum of clinical symptoms. The important role of ECG was covered in the current diagnostic criteria. The role of the epsilon wave (EW) is still under discussion. Aim: The aim of the study was to examine a potential association between the EW and late ventricular potentials (LPs) in ARVC patients (pts). The correlation between RV dilatation or dysfunction and LPs/EW was also analysed. Methods: The ARVC group consisted of 81 pts (53 men, aged 20-78 years) fulfilling 2010 International Task Force Criteria. 12-lead ECG, LPs, Holter, and ECHO were performed in all pts. The presence of EW was analysed in ECG by 3 investigators. LPs were detected by signal-averaged ECG (SAECG). SAECG was considered positive for LPs when at least two of the three following criteria were met: (1) the filtered QRS duration (fQRS) ≥ 114 msec; (2) the duration of the final QRS fragment in which low-amplitude signals lower than 40 µV are recorded (LAS-40 > 38 msec); and (3) the root mean square amplitude of the last 40 milliseconds of the fQRS complex (RMS-40 < 20 µV). The results were compared with a reference group consisting of 53 patients with RV damage in the course of atrial septum defect (ASD) or Ebstein's Anomaly (EA). Results: In the ARVC group, a significant relationship was observed between the occurrence of EW and the presence of LPs. EW was more common in the LP+ than in the LP- patients (48.1% vs. 6.9%, p < 0001; OR 12.5; 95% CI [2.691-58.063]). In ARVC pts, RVOT > 36 mm, RVIT > 41 mm, and RV S' < 9 cm/s were observed significantly more often in the LPs+ than in the LPs- group (OR [95% CI]: 8.3 [2.9-1.5], 6.4 [2.2-19.0] and 3.6 [1.1-12.2], respectively). In the ARVC group, any of fQRS > 114 ms, LAS > 38 ms, and RMS < 20 µV were significantly more frequent in EW+ pts. In multivariate analysis, the independent factors of the EW were LAS-40 and RV S'. In the LPs- subgroup, RVOT > 36 mm was more frequent in ASD/EA than in ARVC (70.4% vs. 25%, p = 0.002). Similarly, in the LPs- subgroup, RVIT > 41 mm was encountered more frequently in ASD/EA than in ARVC (85.2% vs. 48.3%, p = 0.004). Conclusions: In ARVC, there is an association between EW and LPs, with both probably resulting from the same process of fibrofatty substitution of the RV myocardium. Although RV dilatation is common in ASD and EA, it does not correlate with LPs.

The presence of epsilon waves in all precordial leads (V1 -V6 ) in a 13-year-old boy with arrhythmogenic right ventricular dysplasia (ARVD).

Electrocardiographic feature is included in the diagnostic criteria for arrhythmogenic right ventricular dysplasia (ARVD) based on the Revised Task Force criteria 2010. The epsilon wave, which reflects delayed conduction of the right ventricle, is considered to be one of the major diagnostic criteria. We reported a 13-year-old Thai boy with ARVD who presented with ventricular tachycardia. The presence of epsilon wave in all precordial leads (V1 -V6 ) was observed in standard 12-lead EKG. Extensive scarring of the right and left ventricle was seen on cardiac MRI. The extensive Epsilon wave found in this patient may reflect the extensive ventricular wall involvement.

Mega-epsilon waves on 12-lead ECG--just another case of arrhythmogenic right ventricular dysplasia/cardiomyopathy?

Epsilon wave, the post-excitation small squiggles at the beginning of ST segment that first named by Fontaine, is a well-known ECG phenomenon frequently associated with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). Epsilon waves are caused by post excitation of the myocytes in the right ventricle due to myocardial scaring. Increasing evidence suggests that cardiac sarcoidosis might produce the pathological substrate required for production of epsilon waves. Therefore differentiating these two entities is of paramount clinical importance. Here we report a case demonstrating mega-epsilon wave, right ventricular dilatation and inducible ventricular tachycardia (VT) that was initially diagnosed as ARVD/C by the Task Force Criteria. However after a thorough evaluation, diagnosis of cardiac sarcoidosis was confirmed by the evidence of non-caseating granulomas from endomycardial biopsy.

Recurrent Syncope in a Patient With Arrhythmogenic Right Ventricular Cardiomyopathy.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an autosomal inherited cardiac condition characterized by fibroadipose tissue replacement of the right ventricular muscle, leading to structural changes and a high risk for ventricular arrhythmias, a gradual decline in right ventricular function, and sudden cardiac death. ARVC has an autosomal dominant inheritance pattern with variable expression among patients, typically affecting young adults. Genetic mutations affecting the cardiac desmosome genes have been widely reported. Intense exercise has been hypothesized as one of the drivers of ARVC's pathogenesis. Due to its non-specific presentation, it can become a diagnostic challenge for physicians with delayed care. We report a case of a male adult with a history of recurrent syncope and atypical chest pain who developed ventricular tachycardia on admission. This case aims to highlight the unspecific manifestations of ARVC and its main electrocardiographic features for an early diagnosis.