Beatriz Jáuregui

A QRS axis–based algorithm to identify the origin of scar-related ventricular tachycardia in the 17-segment American Heart Association model

BACKGROUND Previously proposed algorithms to predict the ventricular tachycardia (VT) exit site have been based on diverse left ventricular models, but none of them identify the precise region of origin in the electroanatomic map. Moreover, no electrocardiographic (ECG) algorithm has been tested to predict the region of origin of scar-related VTs in patients with nonischemic cardiomyopathy. OBJECTIVE The purpose of this study was to validate a simple ECG algorithm to identify the segment of origin (SgO) of VT relative to the 17-segment American Heart Association model in patients with structural heart disease (SHD). METHODS The study included 108 consecutive patients with documented VT and SHD [77 (71%) with coronary artery disease]. A novel frontal plane axis-based ECG algorithm (highest positive or negative QRS voltage) together with the polarity in leads V3 and V4 was used to predict the SgO of VT. The actual SgO of VT was obtained from the analysis of the electroanatomic map during the procedure. Conventional VT mapping techniques were used to identify the VT exit. RESULTS In total, 149 12-lead ECGs of successfully ablated VT were analyzed. The ECG-suggested SgO matched with the actual SgO in 122 of the 149 VTs (82%). In 21 of the 27 mismatched ECG-suggested SgOs (77.8%), the actual SgO was adjacent to the segment suggested by the ECG. There were no differences in the accuracy of the algorithm based on the SgO or the type of SHD. CONCLUSION This novel QRS axis-based algorithm accurately identifies the SgO of VT in the 17-segment American Heart Association model in patients with SHD.

Image-based criteria to identify the presence of epicardial arrhythmogenic substrate in patients with transmural myocardial infarction

BACKGROUND Patients with transmural myocardial infarction (MI) who undergo endocardial-only substrate ablation are at increased risk for ventricular tachycardia recurrence. Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) can be used to assess infarct transmurality (IT). However, the degree of IT associated with an epicardial arrhythmogenic substrate (AS) has not been determined. OBJECTIVE The purpose of this study was to determine the degree of IT observed by LGE-CMR and multidetector computed tomography (MDCT) that predicts the presence of epicardial AS. METHODS The study included 38 post-MI patients. Ten patients with a subendocardial infarction underwent endocardial-only mapping, and 28 with a classic transmural MI (C-TMI), defined as hyperenhancement ≥75% of myocardial wall thickness (WT), underwent endo-epicardial mapping. LGE-CMR/MDCT data were registered to high-density endocardial or epicardial maps to be analyzed for the presence of AS. RESULTS Of the 28 post-MI patients with C-TMI, 18 had epicardial AS (64%) and 10 (36%) did not. An epicardial scar area ≥14 cm2 on LGE-CMR identified patients with epicardial AS (sensitivity 1, specificity 1). Mean WT in the epicardial scar area in these patients was lower than in patients without epicardial AS (3.14 ± 1.16 mm vs 5.54 ± 1.78 mm; P = .008). A mean WT cutoff value ≤3.59 mm identified patients with epicardial AS (sensitivity 0.91, specificity 0.93). CONCLUSION An epicardial scar area ≥14 cm2 on LGE-CMR and mean CT-WT ≤3.59 mm predict epicardial AS in post-MI patients.

Prediction of premature ventricular complex origin in left vs. right ventricular outflow tract: a novel anatomical imaging approach

Aims Left ventricular (LV) outflow tract ventricular arrhythmias (OTVA) are associated with hypertension (HT), older age, and LV dysfunction, suggesting that LV overload plays a role in the aetiopathogenesis. We hypothesized that anatomical modifications of the LV outflow tract (LVOT) could predict left vs. right OTVA site of origin (SOO). Methods and results Fifty-six (32 men, 53 ± 18 years old) consecutive patients referred for OTVA ablation were included. Cardiac multidetector computed tomography was performed before ablation and then imported to the CARTO system to aid the mapping and ablation procedure. Anatomical characteristics of the aortic root as well as aortopulmonary valvular planar angulation (APVPA) were analysed. The LV was the OTVA SOO (LVOT-VA) in 32 (57%) patients. These patients were more frequently male (78% vs. 22%, P = 0.001), older (57 ± 18 vs. 47 ± 18 years, P = 0.055), and more likely to have HT (59% vs. 21%, P = 0.004), compared to right OTVA patients. Aortopulmonary valvular planar angulation was higher in LVOT-VA patients (68 ± 5° vs. 55 ± 6°, respectively; P < 0.001). Absolute size of all aortic root diameters was associated with LVOT origin. However, after indexing by body surface area, only sinotubular junction diameter maintained a significant association (P = 0.049). Multivariable analysis showed that APVPA was an independent predictor of LVOT origin. Aortopulmonary valvular planar angulation ≥62° reached 94% sensitivity and 83% specificity (area under the curve 0.95) for predicting LVOT origin. Conclusions The measurement of APVPA as a marker of chronic LV overload is useful for the prediction of left vs. right ventricular OTVA origin.

Mini-electrodes help identifying hidden slow conduction during ventricular tachycardia substrate ablation

A 69-year-old male with dilated non-ischemic cardiomyopathy and history of sustained monomorphic VT (SMVT) underwent an unsuccessful VT substrate ablation due to the proximity of the earliest activation site to the conduction system. A second attempt was performed using an ablation catheter with mini-electrodes (ME) and multiple extrastimuli to unveil hidden slow conduction (HSC) sites, allowing the performance of a successful ablation. No SMVT was induced thereafter. ME-obtained electrograms permit to accurately localize areas of HSC sites within ventricular tachycardia (VT) substrates. In our case, this allowed safe ablation during sinus rhythm to eliminate the VT substrate.

Isolated, premature ventricular complex–induced right ventricular dysfunction mimicking arrhythmogenic right ventricular cardiomyopathy

From the *Institut Clínic Cardiovascular, Hospital Clínic, Universitat de Barcelona, Barcelona, Spain, Institut d’Investigacions Biom ediques August Pi i Sunyer (IDIBAPS), Barcelona, Spain, Centro de Investigación Biomédica en Red (CIBER Cardiovascular), Instituto de Salud Carlos III, Madrid, Spain, xDepartment of Electrophysiology, Heart Centre Leipzig, Leipzig, Germany, and kArrhythmia Unit, Virgen del Rocío University Hospital, Seville, Spain.

Influence of myocardial scar on the response to frequent premature ventricular complex ablation

Objective This study aims to evaluate the influence of myocardial scar after premature ventricular complexes (PVC) ablation in patients with left ventricular (LV) dysfunction. Methods 70 consecutive patients (58±11 years, 58 (83%) men, 23% (18–32) mean PVC burden) with LV dysfunction and frequent PVCs submitted for ablation were included. A late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) was performed prior to the ablation and a quantitative and qualitative analysis of the scar was done. Results Left ventricular ejection fraction progressively improved from 34.3%±9% at baseline to 44.4%±12% at 12 months (p<0.01) and 48 (69%) patients were echocardiographic responders. New York Heart Association class improved from 1.96±0.9 points at baseline to 1.36±0.6 at 12 months (p<0.001). Brain natriuretic peptide decreased from 120 (60–284) to 46 (23–81) pg/mL (p=0.04). Twenty-nine (41%) patients showed scar in the preprocedural LGE-CMR with a mean scar mass of 10.4 (5–20) g. Mean scar mass was significantly smaller in responders than in non-responders (0 (0–4.7) g vs 2 (0–14) g, respectively, p=0.017). PVC burden reduction (OR 1.09 (1.01–1.16), p=0.02) and scar mass (OR 0.9 (0.81–0.99), p=0.04) were independent predictors of response, but the former showed a higher accuracy. Conclusions Presence of myocardial scar modulates, but does not preclude, the probability of response to PVC ablation in patients with LV dysfunction.

Clinical Validation of Automatic Local Activation Time Annotation During Focal Premature Ventricular Complex Ablation Procedures

Aims Current navigation systems incorporate algorithms for automatic identification of local activation time (LAT). However, data about their utility and accuracy in premature ventricular complex (PVC) ablation procedures are scarce. This study analyses the accuracy of an algorithmic method based on automatic annotation of the maximal negative slope of the unipolar electrogram within the window demarcated by the bipolar electrogram compared with conventional manual annotation during PVC ablation procedures. Methods and results Forty patients with successful ablation of focal PVC in three centres were included. Electroanatomical activation maps obtained with the automatic system (WF-map) were compared with manual annotation maps (M-map). Correlation and concordance of LAT obtained with both methods were assessed at 3536 points. The distance between the earliest activation site (EAS) and the effective radiofrequency application point (e-RFp) were determined in M-map and WF-map. The distance between WF-EAS and M-EAS was assessed. Successful ablation sites included left ventricular outflow tract (LVOT; 55%), right ventricular outflow tract (40%), and tricuspid annulus (5%). Good correlation was observed between the two annotation approaches (r = 0.655; P < 0.0001). Bland-Altman analysis revealed a systematic delayed detection of LAT by WF-map (bias 33.8 ± 30.9 ms), being higher in LVOT than in the right ventricle (42.6 ± 29.2 vs. 27.2 ± 30.5 ms, respectively; P < 0.0001). No difference in EAS-eRFp distance was observed between M-map and WF-map (1.8 ± 2.8 vs. 1.8 ± 3.4 mm, respectively; P = 0.986). The median (interquartile range) distance between WF-EAS and M-EAS was 2.2(0-6) mm. Conclusion Good correlation was found between M-map and WF-map. Local activation time detection was systematically delayed in WF-map, especially in LVOT. Accurate identification of e-RFp was achieved with both annotation approaches.

Leadless Pacemaker Implantation in a Patient With a Severe Thoracic Deformity

We present the case of a 76-year-old man who was urgently hospitalized for syncope. The electrocardiogram documented atrial fibrillation with high-grade atrioventricular block. The patient’s clinical history included hypertensive heart disease with moderate ventricular dysfunction and permanent atrial fibrillation, as well as a chest deformity due to kyphoscoliosis. During hospitalization, the absence of drugs or analytical abnormalities that could explain the clinical picture was confirmed, and tests showed left ventricular dilatation and dysfunction (ejection fraction = 40%) with normal coronary arteries. Continuous monitoring provided evidence of atrial fibrillation with preserved atrioventricular conduction, but with symptomatic paroxysmal episodes of high-grade block that required isoproterenol administration; a definitive single-chamber pacemaker was indicated. During the implantation procedure, marked venous tortuosity (Figure 1A), related to anterior displacement of the heart due to the barrel chest deformity (Figure 1B), made it impossible to advance the electrode to the superior vena cava from either a right or left approach. The alternative, epicardial implantation, was ruled out because of the patient’s frail clinical status and the drawbacks of a procedure requiring general anesthesia. We decided to implant a leadless pacemaker (Micra, Medtronic Ibérica

Repeated procedures at the generator pocket are a determinant of implantable cardioverter-defibrillator infection

Rates of cardiac‐device infections have increased in recent years, but the current incidence and risk factors for infection in patients with implantable cardioverter‐defibrillators (ICDs) are not well known.