Carine F.B. van Huls van Taxis

Head-to-head comparison of contrast-enhanced magnetic resonance imaging and electroanatomical voltage mapping to assess post-infarct scar characteristics in patients with ventricular tachycardias: real-time image integration and reversed registration

AIMS Substrate-based ablation of ventricular tachycardia (VT) relies on electroanatomical voltage mapping (EAVM). Integration of scar information from contrast-enhanced magnetic resonance imaging (CE-MRI) with EAVM may provide supplementary information. This study assessed the relation between electrogram voltages and CE-MRI scar characteristics using real-time integration and reversed registration. METHODS AND RESULTS Fifteen patients without implantable cardiac defibrillator (14 males, 64 ± 9 years) referred for VT ablation after myocardial infarction underwent CE-MRI. Contours of the CE-MRI were used to create three-dimensional surface meshes of the left ventricle (LV), aortic root, and left main stem (LM). Real-time integration of CE-MRI-derived scar meshes with EAVM of the LV and aortic root was performed using the LM and the CARTO surface registration algorithm. Merging of CE-MRI meshes with EAVM was successful with a registration error of 3.8 ± 0.6 mm. After the procedure, voltage amplitudes of each mapping point were superimposed on the corresponding CE-MRI location using the reversed registration matrix. Infarcts on CE-MRI were categorized by transmurality and signal intensity. Local bipolar and unipolar voltages decreased with increasing scar transmurality and were influenced by scar heterogeneity. Ventricular tachycardia reentry circuit isthmus sites were correlated to CE-MRI scar location. In three patients, VT isthmus sites were located in scar areas not identified by EAVM. CONCLUSION Integration of MRI-derived scar maps with EAVM during VT ablation is feasible and accurate. Contrast-enhanced magnetic resonance imaging identifies non-transmural scars and infarct grey zones not detected by EAVM according to the currently used voltage criteria and may provide important supplementary substrate information in selected patients.

Beneficial effects of catheter ablation on left ventricular and right ventricular function in patients with frequent premature ventricular contractions and preserved ejection fraction

Background Improvement of left ventricular ejection fraction (LVEF) after radiofrequency catheter ablation (RFCA) of frequent premature ventricular contractions (PVCs) has been reported. However, most patients with frequent PVCs have a normal LVEF. In these patients subtle and early forms of PVC-induced left and right ventricular (RV) impairment may not be detected by standard echocardiographic techniques. Objective To assess the effect of frequent PVCs on ventricular function in patients with preserved LVEF. Methods 49 patients (30 male, 49±16 years) with recent-onset (median 1.2 years), frequent PVCs (burden 26±13%) and 25 healthy controls were studied. Thirty-four patients with PVCs underwent successful RFCA. Two-dimensional echocardiography was performed at baseline and follow-up. LV volumes and LVEF were calculated by Simpsons rule. Tricuspid annulus plane systolic excursion and fractional area change were calculated to assess RV function. Multidirectional LV strain (radial, circumferential, longitudinal) and RV free-wall longitudinal strain were calculated by two-dimensional speckle tracking imaging. At baseline LVEF, volumes and RV dimensions were normal in patients and controls. Results Speckle tracking imaging demonstrated reduced LV and RV strain in patients with PVC as compared with controls. At follow-up there were no changes in LVEF, LV volumes and RV dimensions and function in patients successfully treated by RFCA and untreated patients. However, radial, circumferential and longitudinal strain improved significantly in patients after RFCA but remained unchanged in untreated patients. Conclusions Frequent PVCs can induce subtle cardiac dysfunction detected by speckle tracking imaging analysis in patients without apparent cardiomyopathy. RFCA can successfully eliminate PVCs and improve cardiac function.

Contrast-Enhanced MRI-Derived Scar Patterns and Associated Ventricular Tachycardias in Nonischemic Cardiomyopathy Implications for the Ablation Strategy

Background— There are limited data on typical arrhythmogenic substrates and associated ventricular tachycardias (VT) in patients with nonischemic cardiomyopathy. The substrate location may have implications for the ablation strategy. Methods and Results— Nineteen consecutive patients with nonischemic cardiomyopathy (age 58±14 years, 79% men, left ventricular ejection fraction 41±11%) who underwent contrast-enhanced MRI and VT ablation were included. On the basis of 3-dimensional contrast-enhanced MRI–derived scar reconstructions, 8 patients (42%) had predominant basal anteroseptal scar, 9 patients (47%) had predominant inferolateral scar, and 2 patients (11%) had other scar types. Three distinct VT morphologies (≥1 of 3 inducible in 16/19 patients) were associated with underlying scar type. In 9 patients with anteroseptal scar–related VT (8/9 predominant scar, 1/9 nonpredominant), ablation target sites (defined as sites with ≥11/12 pacemap, concealed entrainment or VT termination during ablation) were located in the aortic root and/or anteroseptal left ventricular endocardium in 8 patients (89%) and in the anterior cardiac vein in 1 patient (11%), with additional target sites at the right ventricular septum in 2 patients (22%) and at the epicardium in 1 patient (11%). In contrast, in 8 patients with predominant inferolateral scar–related VT, target sites were located at the epicardium in 5 patients (63%) and in the endocardial inferolateral left ventricle in 3 patients (37%). Conclusions— Two typical scar patterns (anteroseptal and inferolateral) account for 89% of arrhythmogenic substrates in patients with nonischemic cardiomyopathy. Three distinct VT morphologies are highly suggestive of the presence of these scars. Anteroseptal scars were, in general, most effectively approached from the aortic root or anteroseptal left ventricular endocardium, whereas inferolateral scars frequently required an epicardial approach.

Epicardial substrate mapping for ventricular tachycardia ablation in patients with non-ischaemic cardiomyopathy: a new algorithm to differentiate between scar and viable myocardium developed by simultaneous integration of computed tomography and contrast-enhanced magnetic resonance imaging.

AIMS During epicardial electroanatomical mapping (EAM), it is difficult to differentiate between fibrosis and fat, as both exhibit attenuated bipolar voltage (BV). The purpose of this study was to assess whether unipolar voltage (UV), BV, and electrogram characteristics (EC) can distinguish fibrosis from viable myocardium and fat during epicardial EAM for ventricular tachycardia (VT) ablation in non-ischaemic cardiomyopathy (NICM). METHODS AND RESULTS Ten NICM patients (7 males, 56 ± 13 years) with VT underwent epicardial EAM with real-time integration of computed tomography-derived epicardial fat and contrast-enhanced MRI-derived scar. Bipolar voltage (filtered 30-400 Hz), UV (filtered 1-240 Hz), and EC (duration and morphology) were correlated with the presence of fat and scar. At sites devoid of fat, the optimal cutoff values to differentiate between scar and myocardium were 1.81 mV for BV and 7.95 mV for UV. Bipolar voltage, UV, and electrogram duration >50 ms distinguished scar from myocardium in areas covered with <2.8 mm fat (all P < 0.001), but not ≥ 2.8 mm fat. In contrast, electrogram morphology-characteristics could also detect scar covered with ≥ 2.8 mm fat (P = 0.001). A newly developed three-step algorithm combining electrogram morphology, duration, and UV could correctly identify scar with a sensitivity of 75%. Unipolar voltage but not BV could detect intramural scar in the absence of fat. CONCLUSIONS Both BV ≤ 1.81 mV and UV ≤ 7.95 mV are useful for detection of scar during epicardial EAM, in the absence of ≥ 2.8 mm fat. However, EC can be used to detect scar covered with fat. A newly developed algorithm combining UV and EC can differentiate between scar and viable myocardium. Unipolar voltage but not BV could detect intramural scar.

Real-time integration of MDCT-derived coronary anatomy and epicardial fat: impact on epicardial electroanatomic mapping and ablation for ventricular arrhythmias.

OBJECTIVES This study aimed to evaluate the feasibility and accuracy of real-time integration of multidetector computed tomography (MDCT) derived coronary anatomy and epicardial fat distribution and its impact on electroanatomical mapping and ablation. BACKGROUND Epicardial catheter ablation for ventricular arrhythmias (VA) is an important therapeutic option in patients after endocardial ablation failure. However, epicardial mapping and ablation are limited by the presence of coronary arteries and epicardial fat. METHODS Twenty-eight patients (21 male, age 59 ± 16 years) underwent combined endo-epicardial electroanatomical mapping. Prior to the procedure, MDCT derived coronary anatomy and epicardial fat meshes were loaded into the mapping system (CARTO XP, Biosense Webster Inc, Diamond Bar, California). Real-time registration of MDCT data was performed after endocardial mapping. The distance between epicardial ablation sites and coronary arteries was assessed by registered MDCT and angiography. After the procedure, mapping and ablation points were superimposed on the MDCT using a reversed registration matrix for head-to-head comparison of mapping data and corresponding fat thickness. RESULTS Image registration was successful and accurate in all patients (position error 2.8 ± 1.3 mm). At sites without evidence for scar, epicardial bipolar voltage decreased significantly (p < 0.001) with increasing fat thickness. Forty-six VA were targeted; 25 (54%) were abolished by catheter ablation, in 21 (46%) ablation failed. In 5 VA no target site was identified and in 3 VA adhesions prevented mapping. In 2 VA ablation was withheld due to His-bundle vicinity and in 7 VA due to proximity of coronary arteries. In 4 VA catheter ablation was ineffective. At ineffective ablation sites epicardial fat was significantly thicker compared to successful sites (16.9 ± 6.8 mm [range 7.3 to 22.2 mm] and 1.5 ± 2.1 mm [range 0.0 to 6.1 mm], p = 0.002). CONCLUSIONS Real-time image integration of pre-acquired MDCT information is feasible and accurate. Epicardial fat >7 mm and the presence of coronary arteries are important reasons for epicardial ablation failure. Visualization of fat thickness during the procedure may facilitate interpretation of bipolar electrograms and identification of ineffective ablation sites.

Early reperfusion therapy affects inducibility, cycle length, and occurrence of ventricular tachycardia late after myocardial infarction.

Background— This study aimed to evaluate the impact of early reperfusion during acute myocardial infarction (MI) on ventricular tachycardia (VT) inducibility, inducible VT cycle length (CL), and occurrence of spontaneous VT late after MI. Methods and Results— Five hundred six patients (440 men; age, 63±11 years) with prior MI who underwent electrophysiology study before implantation of an implantable cardioverter-defibrillator for primary or secondary prevention were assessed. Patients were classified according to the reperfusion strategy (reperfusion: thrombolysis, n=44, or percutaneous coronary intervention, n=65, versus no reperfusion, n=397) during acute MI. Monomorphic sustained VT was inducible in 351 (69%) patients. Inducibility in reperfused and nonreperfused patients was similar in primary prevention patients (56% versus 58%) but significantly higher for nonreperfused patients in secondary prevention patients (56% versus 79%, P=0.001). Induced VTCL was shorter (247±40 versus 287±63, P<0.001) and very fast VT (CL ⩽250 ms) was more often induced in reperfused patients (71% versus 47%, P=0.001). In primary prevention patients, nonreperfusion was associated with a doubled risk for first spontaneous VT during follow-up. Conclusions— There are important differences in VT inducibility, induced VTCL, and occurrence of spontaneous VT in the chronic infarct healing phase between patients with and those without successful reperfusion during acute MI. These findings suggest differences in the chronic arrhythmogenic substrate.

Reversed polarity of bipolar electrograms for predicting a successful ablation site in focal idiopathic right ventricular outflow tract arrhythmias

BACKGROUND Radiofrequency catheter ablation (RFCA) for idiopathic right ventricular outflow tract (RVOT) arrhythmias is typically guided by local activation time (LAT) mapping and unipolar electrogram morphology (QS configuration). However, LAT mapping is limited by the large variation among patients, and the area demonstrating a QS configuration of the unipolar electrogram may be larger than the focal source. Reversed polarity has been proposed as a criterion for guiding RFCA. OBJECTIVE The purpose of this study was to investigate the value of reversed polarity of adjacent bipolar electrograms for predicting a successful ablation site in idiopathic RVOT arrhythmias. METHODS Twenty-five consecutive patients (12 men [48%], age 43 ± 15 years) undergoing RFCA for RVOT arrhythmia were studied. Electrograms of ablation sites and of points within a 15-mm radius to the successful site were evaluated for LAT, unipolar electrogram morphology, and the presence of reversed polarity of adjacent bipolar electrograms. Electrogram characteristics of successful ablation sites were compared to those of nonsuccessful ablation sites. The spatial distribution of each electrogram characteristic was studied. RESULTS Successful ablation sites more often demonstrated reversed polarity and had an earlier LAT than nonsuccessful sites. A wide spatial distribution was observed for unipolar electrograms with a QS configuration around the successful ablation site. Mapping based on LAT and reversed polarity had a higher predictive value for a successful ablation site than mapping based on LAT and QS configuration. CONCLUSION The presence of reversed polarity has a high predictive value for successful ablation sites in focal idiopathic RVOT arrhythmias and is likely to reduce the number of RFCA applications.

Influence of Steroid Therapy on the Incidence of Pericarditis and Atrial Fibrillation After Percutaneous Epicardial Mapping and Ablation for Ventricular Tachycardia

Background—This study evaluates the influence of 3 therapeutic approaches on the incidence of pericarditis and atrial fibrillation (AF) after percutaneous epicardial mapping and ablation for ventricular tachycardia. Methods and Results—Eighty-five consecutive procedures (2006–2011) were retrospectively reviewed. After the first 17 procedures (20.0%), no steroids were administered. For the subsequent 30 procedures (35.3%), systemic steroids were administered intravenously or orally, whereas the last 38 procedures (44.7%) were followed by intrapericardial steroid injection. Compared with no steroids, the incidence of pericarditic chest pain was significantly reduced by intrapericardial steroids (58.8% versus 21.1%; P=0.006) but not by intravenous or oral steroids (58.8% versus 43.4%; P=0.31). There was no significant difference in the incidence of pericarditic ECG with steroids (36.8%, 30.0%, and 41.2% for intrapericardial, intravenous or oral, and none, respectively). There was a nonsignificant reduced incidence of chest pain with ECG changes with steroids (13.2%, 10.0%, and 29.4% for intrapericardial, intravenous or oral, and none, respectively). Radiofrequency applications (65.9% of procedures) did not affect the incidence of pericarditic ECG changes, pericarditic chest pain, or pericarditis (all P>0.05). In 7 (8.3%) patients with no prior history of AF, AF was documented a median 36 hours after procedure. Patients with pericarditic ECG tended to be at greater risk of AF (16.7 versus 3.6%; P=0.091). Conclusions—There is a high incidence of pericarditic chest pain and ECG changes after epicardial ventricular tachycardia mapping and ablation. Pericarditic chest pain is significantly decreased by intrapericardial steroids. Procedure-related AF is relatively frequent and tends to occur more commonly with pericarditic ECG changes.

Fatigue as Presenting Symptom and a High Burden of Premature Ventricular Contractions Are Independently Associated With Increased Ventricular Wall Stress in Patients With Normal Left Ventricular Function

Background—High idiopathic premature ventricular contractions (PVC) burden has been associated with PVC-induced cardiomyopathy. Patients may be symptomatic before left ventricular (LV) dysfunction develops. N-terminal pro–B-type natriuretic peptide (NT-proBNP) and circumferential end-systolic wall stress (cESS) on echocardiography are markers for increased ventricular wall stress. This study aimed to evaluate the relation between presenting symptoms, PVC burden, and increased ventricular wall stress in patients with frequent PVCs and preserved LV function. Methods and Results—Eighty-three patients (41 men; 49±15 years) with idiopathic PVCs and normal LV function referred for PVC ablation were included. Type of symptoms (palpitations, fatigue, and [near-]syncope), PVC burden on 24-hour Holter, NT-proBNP levels, and cESS on echocardiography were assessed before and 3 months after ablation. Sustained successful ablation was defined as ≥80% PVC burden reduction during follow-up. Patients were symptomatic for 24 months (Q1–Q3, 16–60); 73% reported palpitations, 47% fatigue, and 30% (near-)syncope. Baseline PVC burden was 23±13%, median NT-proBNP 92 pg/mL (Q1–Q3 50–156), and cESS 143±35 kdyne/cm2. Fatigue was associated with higher baseline NT-proBNP and cESS (P<0.001, P=0.011, respectively). After sustained successful ablation, achieved in 81%, NT-proBNP and cESS decreased significantly (P<0.001 and P=0.036, respectively). Fatigue was independently associated with a significantly larger reduction in NT-proBNP. In patients with nonsuccessful ablation, NT-proBNP and cESS remained unchanged. Conclusions—In patients with frequent PVCs and preserved LV function, fatigue was associated with higher baseline NT-proBNP and cESS, and with a significantly larger reduction in NT-proBNP after sustained successful ablation. These findings support a link between fatigue and PVC-induced increased ventricular wall stress, despite preserved LV function.

Programmed electrical stimulation-guided encircling cryoablation concomitant to surgical ventricular reconstruction for primary prevention of ventricular arrhythmias

OBJECTIVES Surgical ventricular reconstruction (SVR) is an effective treatment to improve left ventricular (LV) function in patients with ischaemic heart failure and an LV anterior-apical aneurysm. Ventricular arrhythmia (VA) is an important cause for morbidity and mortality in these patients. Therefore, encircling cryoablation targeting the VA substrate may be required. Programmed electrical stimulation (PES) can identify patients at risk for VA. The objective of this study was to evaluate the incidence and type of VA during long-term follow-up after PES-guided encircling cryoablation concomitant to SVR for primary prevention of VA. METHODS Thirty-eight patients without spontaneous VA referred for SVR who underwent preoperative PES were included (PES group); 27 (71%) patients inducible for aneurysm-related VA received cryoablation. A historical cohort of 39 patients without spontaneous VA, preoperative PES and antiarrhythmic surgery served as the control group. Patients were discharged with an implantable cardioverter defibrillator (ICD). RESULTS During 74 ± 35 months of follow-up, no arrhythmic deaths occurred. Five-year survival for the total study population was 78%. Twenty-eight (36%) patients experienced ≥1 VA. There were no differences in the number and type of ICD therapies between groups: shocks, P = 0.699 and antitachypacing, P = 0.403. Five-year VA-free survival was 61% for the PES group and 65% for the control group (hazard ratio 1.67, P = 0.290). CONCLUSIONS The majority of the patients referred for SVR without previously documented VA was inducible for aneurysm-related VA. During the follow-up, more than one-third of the patients experienced sustained VA and 25% received appropriate ICD therapy. No difference in VA occurrence or ICD therapy was observed between groups.