Benefits of chronic total coronary occlusion percutaneous intervention in patients with heart failure and reduced ejection fraction: insights from a cardiovascular magnetic resonance study.

BACKGROUND: Chronic total occlusion percutaneous coronary intervention (CTO-PCI) can improve angina and left ventricular ejection fraction (LVEF). These benefits were not assessed in populations with heart failure with reduced ejection fraction (HFrEF). We studied the effect of CTO-PCI on left ventricular function and clinical parameters in patients with HFrEF. METHODS: Using cardiovascular magnetic resonance (CMR), we studied 29 patients with HFrEF and evidence of viability and/or ischemia in the territory supplied by a CTO who were successfully treated with CTO-PCI. In patients with multi-vessel disease, non-CTO PCI was also performed. Imaging parameters, clinical status, and brain natriuretic peptide (BNP) levels were evaluated before and 6 months after CTO-PCI. RESULTS: A decrease in left ventricular end-systolic volume (160 ± 54 ml vs. 143 ± 58 ml; p = 0.029) and an increase in LVEF (31.3 ± 7.4 % vs. 37.7 ± 8 %; p < 0.001) were observed. There were no differences in LVEF improvement between patients who underwent non-CTO PCI (n = 11) and those without this intervention (n = 18); (p = 0.73). The number of segments showing perfusion defects was significantly reduced (0.5 ± 1 vs. 0.2 ± 0.5; p = 0.043). Angina (p = 0.002) and NYHA functional class (p = 0.004) improved, and BNP levels decreased (p = 0.004) after CTO-PCI. CONCLUSIONS: In this group of patients with HFrEF showing CMR evidence of viability and/or ischemia within the territory supplied by the CTO, an improvement in ejection fraction, left ventricular end-systolic volume and ischemia burden was observed after CTO-PCI. Clinical and laboratory parameters also improved. TRIAL REGISTRATION: ClinicalTrials.gov NCT02570087 . Registered 6 October 2015.

Reversal of spherical remodelling of the left atrium after pulmonary vein isolation: incidence and predictors.

AIMS: Pulmonary vein isolation (PVI) induces left atrial (LA) volume reduction, known as reverse remodelling (RR). The related changes in LA shape have not yet been evaluated. Left atrial sphericity (LASP) is a new shape-based marker of remodelling that compares LA geometry and a perfect sphere and is a powerful predictor of PVI success. We aimed to evaluate the effect of PVI on LASP and describe the concept of spherical and volumetric RR. METHODS AND RESULTS: Left atrial sphericity and volume were automatically obtained with self-customized software using a magnetic resonance imaging-based three-dimensional reconstruction of LA. Reverse remodelling was defined as improvement in LASP (spherical RR) or volume reduction (volumetric RR). In a series of 102 patients, spherical and volumetric RR was observed in 42.2 and 69%, respectively. Patients with paroxysmal atrial fibrillation (AF) had higher probability to present spherical RR as compared with patients with persistent AF (50.8 vs. 29.3%, P = 0.03). Patients with persistent AF showed significant post-procedural worsening of LASP (81.9 vs. 82.9%, P = 0.04). Patients with no recurrence showed a trend towards a higher proportion of spherical RR compared with those with recurrences (46.2 vs. 32.4%, respectively); no differences were observed in volumetric RR (62.1 vs. 62.9%, respectively). Paroxysmal AF was the only independent predictor of spherical RR. CONCLUSION: Pulmonary vein isolation leads to spherical RR in a substantial proportion of patients, and in higher proportion of patients with paroxysmal AF. Reverse remodelling may be caused by a combination of scarring and myocardial structural recovery. Changes in LASP might be more specific than volume reduction to detect favourable remodelling.

Left atrial sphericity: a new method to assess atrial remodeling. Impact on the outcome of atrial fibrillation ablation.

BACKGROUND: Atrial fibrillation (AF) ablation outcome is mainly determined by atrial remodeling that, nowadays, is only estimated through clinical presentation (persistent vs. paroxysmal) and left atrial (LA) dimension. The aim of the study was to stage the atrial remodeling process using the Left Atrial Sphericity (LASP) and determine whether this technique may help to predict AF ablation outcome. METHODS: Consecutive patients who underwent contrast-enhanced cardiac magnetic resonance angiography before AF ablation were included in the study. Three-dimensional reconstruction of LA excluding pulmonary veins and the LA appendage was used to define the LA cavity. The LASP was automatically obtained with self-customized software. RESULTS: 106 patients were included and categorized in 3 groups (Gs): discoid-LA (G1), intermediate-LA (G2), and spherical-LA (G3). The G3 patients had larger LA anteroposterior diameter than G1 and G2 patients (47 ± 7 vs 43 ± 6 and 39 ± 5 mm; P < 0.001), greater LA volume (90 ± 39 vs 86 ± 24 and 73 ± 20 mm; P = 0.012), and higher prevalence of persistent AF (75% vs 48% and 29%; P = 0.034) structural heart disease (75% vs 19% and 19%; P < 0.001), and AF recurrence at 12 months follow-up (58% vs 29% and 5%, P < 0.001). The LASP had linear correlation to predicted probability of recurrence. Multivariate analysis identified LASP (OR 1.320 [1.096-1.591], P = 0.004) and hypertension (OR 3.694 [1.282-10.645]; P = 0.016) as independent risk factors for arrhythmia recurrence. CONCLUSION: Left Atrial Sphericity is a new independent predictor of recurrence after AF ablation and may be useful in selecting the best candidates for AF ablation.

Mechanical abnormalities detected with conventional echocardiography are associated with response and midterm survival in CRT.

OBJECTIVES: Our aim was to identify "correctable abnormalities" using conventional grayscale and blood-pool Doppler echocardiography and evaluate their ability to predict both response and midterm survival. BACKGROUND: Identification of mechanical abnormalities that may be corrected with cardiac resynchronization therapy (CRT) is useful for predicting echocardiographic response at 1-year follow-up. METHODS: A total of 200 CRT patients were included. Clinical evaluation and echocardiography were performed before and after CRT to assess the presence of the mechanical abnormalities of interest (septal flash, abnormal ventricular filling, or exaggerated interventricular dependence). Response to CRT was defined as a reduction in left ventricular (LV) end-systolic volume (ESV) ≥15%. Four subgroups of extent of response were defined: LVESV reduction >26.68% (extensive remodeling); LVESV reduction 6.8% to 26.68% (slight remodeling); LVESV reduction <6.8% (no remodeling) and clinical response; and LVESV reduction <6.8% without clinical response or the occurrence of death or heart transplantation. Midterm cardiovascular survival was evaluated (mean follow-up 38 ± 19 months). RESULTS: The presence of a correctable abnormality was independently associated with a better rate (odds ratio: 0.03 [95% confidence interval (CI): 0.01 to 0.10], p < 0.001) and extent of response to CRT (n = 59 [96.7%] for the extensive remodeling subgroup vs. n = 53 [85.5%] for the slight remodeling subgroup vs. n = 19 [47.5%] for the no remodeling with clinical response subgroup vs. n = 17 [45.9%] for the no remodeling without clinical response subgroup, p = 0.0001), as well as with increased midterm survival (hazard ratio: 0.11 [95% CI: 0.2 to 0.6]). Other independent predictors included creatinine level and LV end-systolic diameter for response; New York Heart Association functional class IV, creatinine, LV end-systolic diameter, and transmurality index for extent of response; and New York Heart Association functional class IV for cardiovascular mortality. CONCLUSIONS: The presence of a correctable abnormality evaluated by conventional echocardiography is associated with LV reverse remodeling and better survival at midterm follow-up. Clinical characteristics and myocardial viability also have an influence.

Three-dimensional architecture of scar and conducting channels based on high resolution ce-CMR: insights for ventricular tachycardia ablation.

BACKGROUND: Conducting channels are the target for ventricular tachycardia (VT) ablation. Conducting channels could be identified with contrast enhanced-cardiac magnetic resonance (ce-CMR) as border zone (BZ) corridors. A 3-dimensional (3D) reconstruction of the ce-CMR could allow visualization of the 3D structure of these BZ channels. METHODS AND RESULTS: We included 21 patients with healed myocardial infarction and VT. A 3D high-resolution 3T ce-CMR was performed before CARTO-guided VT ablation. The left ventricular wall was segmented and characterized using a pixel signal intensity algorithm at 5 layers (endocardium, 25%, 50%, 75%, epicardium). A 3D color-coded shell map was obtained for each layer to depict the scar core and BZ distribution. The presence/characteristics of BZ channels were registered for each layer. Scar area decreased progressively from endocardium to epicardium (scar area/left ventricular area: 34.0±17.4% at endocardium, 24.1±14.7% at 25%, 16.3±12.1% at 50%, 13.1±10.4 at 75%, 12.1±9.3% at epicardium; P<0.01). Forty-five BZ channels (2.1±1.0 per patient, 23.7±12.0 mm length, mean minimum width 2.5±1.5 mm) were identified, 85% between the endocardium and 50% shell and 76% present in ≥1 layer. The ce-CMR-defined BZ channels identified 74% of the critical isthmus of clinical VTs and 50% of all the conducting channels identified in electroanatomic maps. CONCLUSIONS: Scar area in patients with healed myocardial infarction decreases from the endocardium to the epicardium. BZ channels, more commonly seen in the endocardium, display a 3D structure within the myocardial wall that can be depicted with ce-CMR. The use of ce-CMR-derived maps to guide VT ablation warrants further investigation.

Integration of 3D electroanatomic maps and magnetic resonance scar characterization into the navigation system to guide ventricular tachycardia ablation.

BACKGROUND: Scar heterogeneity identified with contrast-enhanced cardiac magnetic resonance (CE-CMR) has been related to its arrhythmogenic potential by using different algorithms. The purpose of the study was to identify the algorithm that best fits with the electroanatomic voltage maps (EAM) to guide ventricular tachycardia (VT) ablation. METHODS AND RESULTS: Three-dimensional scar reconstructions from preprocedural CE-CMR study at 3T were obtained and compared with EAMs of 10 ischemic patients submitted for a VT ablation. Three-dimensional scar reconstructions were created for the core (3D-CORE) and border zone (3D-BZ), applying cutoff values of 50%, 60%, and 70% of the maximum pixel signal intensity to discriminate between core and BZ. The left ventricular cavity from CE-CMR (3D-LV) was merged with the EAM, and the 3D-CORE and 3D-BZ were compared with the corresponding EAM areas defined with standard cutoff voltage values. The best match was obtained when a cutoff value of 60% of the maximum pixel signal intensity was used, both for core (r(2)=0.827; P<0.001) and BZ (r(2)=0.511; P=0.020), identifying 69% of conducting channels (CC) observed in the EAM. Matching improved when only the subendocardial half of the wall was segmented (CORE: r(2)=0.808; P<0.001 and BZ: r(2)=0.485; P=0.025), identifying 81% of CC. When comparing the location of each bipolar voltage intracardiac electrogram with respect to the 3D CE-CMR-derived structures, a Cohen κ coefficient of 0.70 was obtained. CONCLUSIONS: Scar characterization by means of high resolution CE-CMR resembles that of EAM and can be integrated into the CARTO system to guide VT ablation.

Relation of plasma brain natriuretic peptide levels on admission for ST-elevation myocardial infarction to left ventricular end-diastolic volume six months later measured by both echocardiography and cardiac magnetic resonance.

The main objective of this study was to investigate the relation between brain natriuretic peptide (BNP) levels within the first 96 hours after ST-segment elevation acute myocardial infarction (STEMI) and the development of left ventricular (LV) dilatation at 6-month follow-up. Eighty-two patients with first STEMIs, reperfused within 12 hours of symptom onset, were prospectively included. Plasma BNP was determined on admission and at 1- and 6-month follow-up. Clinically significant LV dilatation, defined as a >20% increase in LV end-diastolic volume at 6-month follow-up, was assessed using echocardiography and cardiac magnetic resonance. Thirty-two percent of patients developed clinically significant LV dilatation. BNP values on admission and at follow-up were significantly higher in patients who developed clinically significant LV dilatation at 6 months (182 +/- 117 vs 106 +/- 91 pmol/ml). After adjusting for age, infarct size, E-wave deceleration time, and the LV ejection fraction, BNP on admission was an independent predictor of LV dilatation, whether assessed by echocardiography (B = 0.075, p = 0.04) or cardiac magnetic resonance (B = 0.085, p = 0.04). In conclusion, high BNP levels on admission and at follow-up predict LV dilatation after STEMI. The early determination of plasma BNP upon admission for STEMI could be helpful in identifying patients at higher risk for LV dilatation, in whom aggressive management is warranted.