Prognostic Value of Endocardial Voltage Mapping in Patients With Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia

Abstract

Background-Endocardial voltage mapping (EVM) identifies low-voltage right ventricular (RV) areas, which may representthe electroanatomic scar substrate of life-threatening tachyarrhythmias. We prospectively assessed the prognostic value of EVM in a consecutive series of patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D). Methods and Results-We studied 69 consecutive ARVC/D patients (47 males; median age 35 years [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45]) who underwent electrophysiological study and both bipolar and unipolar EVM. The extent of confluent bipolar (<1.5 mV) and unipolar (<6.0 mV) low-voltage electrograms was estimated using the CARTO-incorporated area calculation software. Fifty-three patients (77%) showed ≥1 RV electroanatomic scars with an estimated burden of bipolar versus unipolar lowvoltage areas of 24.8% (7.2-31.5) and 64. 8% (39.8-95.3), respectively (P=0.009). In the remaining patients with normal bipolar EVM (n=16; 23%), the use of unipolar EVM unmasked ≥1 region of low-voltage electrogram affecting 26.2% (11.6-38.2) of RV wall. During a median follow-up of 41 (28-56) months, 19 (27.5%) patients experienced arrhythmic events, such as sudden death (n=1), appropriate implantable cardioverter defibrillator interventions (n=7), or sustained ventricular tachycardia (n=11). Univariate predictors of arrhythmic outcome included previous cardiac arrest or syncope (hazard ratio=3.4; 95% confidence interval, 1.4-8.8; P=0.03) and extent of bipolar low-voltage areas (hazard ratio=1.7 per 5%; 95% confidence interval, 1.5-2; P<0.001), whereas the only independent predictor was the bipolar low-voltage electrogram burden (hazard ratio=1.6 per 5%; 95% confidence interval, 1.2-1.9; P<0.001). Patients with normal bipolar EVM had an uneventful clinical course. by genetically-determined myocardial loss and fibrofatty replacement and may provide a substrate for life-threatening re-entrant ventricular tachyarrhythmias. 4,[11][12][13][14] The assessment of mechanical consequences of myocardial fibrofatty scar has been traditionally based on imaging techniques such as echocardiography and angiography. 15,16 Among the techniques now available for direct imaging of ventricular myocardial lesion, endocardial voltage mapping (EVM) is an emerging tool that has the ability to accurately identify and quantify RV regions with low-amplitude electric signals (ie, electroanatomic scar areas), which reflect myocardial replaced tissue. [17][18][19][20][21][22][23][24] Although the technique has been demonstrated to enhance the accuracy for diagnosing ARVC/D, its value for arrhythmic risk stratification remains to be established. Hence this study was designed to prospectively evaluate the prognostic value of RV EVM in a cohort of ARVC/D patients during a long-term follow-up. Conclusions-The Methods Study PopulationThe study population included 69 consecutive patients (47 males; median age 35 years [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45])...

Role of Ventricular Tachycardia Ablation in Arrhythmogenic Right Ventricular Cardiomyopathy

“…Among the tools available for direct imaging of ventricular myocardial lesions, bipolar threedimensional electroanatomic voltage mapping (3D-EVM) accurately identifies the presence, location, and extent of the pathological substrate of ARVC by detection of low-voltage regions, that reflect the electric consequences of transmural myocyte loss and fibrofatty replacement, observed at histopathological examinations ( Figure 1). 19 A good concordance between the presence and location of RV low-voltage areas identified by 3D-EVM and akinetic/dyskinetic regions detected by echocardiography or angiography was demonstrated. 20 Moreover, 3D-EVM is significantly more sensitive than cardiac magnetic resonance to identify RV scar lesions.…”

“…This may allow to record electrical activities within areas of very low voltage (dense scar), revealing surviving myocardial bundles that may represent the substrate for re-entrant circuits within the scar that may otherwise be overlooked. 25 Besides its diagnostic value, bipolar 3D-EVM also carries prognostic significance, as one study demonstrated that the presence and extent of bipolar low voltage areas is an independent predictor of arrhythmic events, over and above classical risk factors like clinical history, arrhythmic background and ventricular dysfunction, 19 and another study that the fragmented electrograms are significantly associated with arrhythmic events during follow-up. 26 Endocardial bipolar EVM can fail to detect low-voltage areas in about 25-30% of ARVC patients with VT, 19,27 and endocardial ablation approach provides only a modest freedom from VT recurrence.…”

“…25 Besides its diagnostic value, bipolar 3D-EVM also carries prognostic significance, as one study demonstrated that the presence and extent of bipolar low voltage areas is an independent predictor of arrhythmic events, over and above classical risk factors like clinical history, arrhythmic background and ventricular dysfunction, 19 and another study that the fragmented electrograms are significantly associated with arrhythmic events during follow-up. 26 Endocardial bipolar EVM can fail to detect low-voltage areas in about 25-30% of ARVC patients with VT, 19,27 and endocardial ablation approach provides only a modest freedom from VT recurrence. 27 This is related to the pathogenesis of the disease: as proved by autopsy and pathology studies, the wavefront of fibrofatty myocardial replacement progresses from the epicardium to the endocardium, so that the scar tissue can either involve the whole thickness of ventricular wall or be confined to epicardial/midmural layers, sparing the endocardial regions.…”

Arrhythmogenic Cardiomyopathy

“…Noteworthy, because of the wavefront progression of RV fibro-fatty replacement from the epicardium to the endocardium, scar tissue in non-advanced stages may be confined to epicardial/midmural layers, sparing (or reaching focally) the endocardial region. Thus, bipolar endocardial voltage mapping of the RV free wall may underestimate or miss nontransmural low-voltage areas [39]. Finally, in people performing sport activity, AC should be distinguished from so-called "athlete heart", i.e.…”

Arrhythmogenic Cardiomyopathy: Electrical and Structural Phenotypes

“…[132][133][134][135] The diagnostic and prognostic utility of EAM has not been implemented in the current TFC, but recent data indicate that it can be useful for diagnosis and risk stratification. 136 …”