Markus Linhart

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

BACKGROUNDnPatients 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.nnnOBJECTIVEnThe 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.nnnMETHODSnThe 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.nnnRESULTSnOf 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).nnnCONCLUSIONnAn 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

AimsnLeft 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).nnnMethods and resultsnFifty-six (32 men, 53u2009±u200918u2009years 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%, Pu2009=u20090.001), older (57u2009±u200918 vs. 47u2009±u200918u2009years, Pu2009=u20090.055), and more likely to have HT (59% vs. 21%, Pu2009=u20090.004), compared to right OTVA patients. Aortopulmonary valvular planar angulation was higher in LVOT-VA patients (68u2009±u20095° vs. 55u2009±u20096°, respectively; Pu2009<u20090.001). 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 (Pu2009=u20090.049). 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.nnnConclusionsnThe measurement of APVPA as a marker of chronic LV overload is useful for the prediction of left vs. right ventricular OTVA origin.

Rationale and design of the TRICHAMPION trial: Triple Chamber Pacing in Hypertrophic Obstructive Cardiomyopathy Patients

PurposeDual-chamber (DDD) pacing has been used for treatment of patients with hypertrophic obstructive cardiomyopathy (HOCM). Due to inconclusive results in prior trials, current guidelines assign DDD pacing a class IIb indication in selected patients. Prior observations indicate that lack of clinical improvement may result from suboptimal effect of DDD pacing with non-physiological AV intervals due to fusion of intrinsic and paced QRS complex.MethodsThe Triple Chamber Pacing in Hypertrophic Obstructive Cardiomyopathy Patients (TRICHAMPION) trial is a prospective, randomized, single-blinded, multicenter study to investigate the benefit of atrial synchronous biventricular pacing (CRT-P) in highly symptomatic HOCM patients with severe left ventricular outflow tract (LVOT) obstruction who are not candidates for ablative therapies. AV node ablation is used as key tool to optimize AV intervals in patients with QRS fusion. The primary endpoint is the percentage of patients with symptomatic improvement at 12xa0months, defined as improvement of New York Heart Association functional class, in the Minnesota Living with Heart Failure Questionnaire score and increased cardiopulmonary exercise endurance.ConclusionsThe aim of the TRICHAMPION trial is to investigate the benefit of optimized atrial synchronous biventricular pacing in absence of QRS fusion in highly symptomatic HOCM patients with severe LVOT obstruction who are not candidates for ablative therapies.

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)u2009g vs 2 (0–14)u2009g, 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.

Automatic activation mapping and origin identification of idiopathic outflow tract ventricular arrhythmias

PURPOSEnActivation mapping is used to guide ablation of idiopathic outflow tract ventricular arrhythmias (OTVAs). Isochronal activation maps help to predict the site of origin (SOO): left vs right outflow tract (OT). We evaluate an algorithm for automatic activation mapping based on the onset of the bipolar electrogram (EGM) signal for predicting the SOO and the effective ablation site in OTVAs.nnnMETHODSnEighteen patients undergoing ablation due to idiopathic OTVAs were studied (12 with left ventricle OT origin). Right ventricle activation maps were obtained offline with an automatic algorithm and compared with manual annotation maps obtained during the intervention. Local activation time (LAT) accuracy was assessed, as well as the performance of the 10ms earliest activation site (EAS) isochronal area in predicting the SOO.nnnRESULTSnHigh correlation was observed between manual and automatic LATs (Spearmans: 0.86 and Lins: 0.85, both p<0.01). The EAS isochronal area were closely located in both map modalities (5.55 ± 3.56mm) and at a similar distance from the effective ablation site (0.15±2.08mm difference, p=0.859). The 10ms isochronal area longitudinal/perpendicular diameter ratio measured from automatic maps showed slightly superior SOO identification (67% sensitivity, 100% specificity) compared with manual maps (67% sensitivity, 83% specificity).nnnCONCLUSIONSnAutomatic activation mapping based on the bipolar EGM onset allows fast, accurate and observer-independent identification of the SOO and characterization of the spreading of the activation wavefront in OTVAs.