Progressive and Simultaneous Right and Left Atrial Remodeling Uncovered by a Comprehensive Magnetic Resonance Assessment in Atrial Fibrillation.

Background Left atrial structural remodeling contributes to the arrhythmogenic substrate of atrial fibrillation (AF), but the role of the right atrium (RA) remains unknown. Our aims were to comprehensively characterize right atrial structural remodeling in AF and identify right atrial parameters predicting recurrences after ablation. Methods and Results A 3.0 T late gadolinium enhanced-cardiac magnetic resonance was obtained in 109 individuals (9 healthy volunteers, 100 patients with AF undergoing ablation). Right and left atrial volume, surface, and sphericity were quantified. Right atrial global and regional fibrosis burden was assessed with validated thresholds. Patients with AF were systematically followed after ablation for recurrences. Progressive right atrial dilation and an increase in sphericity were observed from healthy volunteers to patients with paroxysmal and persistent AF; fibrosis was similar among the groups. The correlation between parameters recapitulating right atrial remodeling was mild. Subsequently, remodeling in both atria was compared. The RA was larger than the left atrium (LA) in all groups. Fibrosis burden was higher in the LA than in the RA of patients with AF, whereas sphericity was higher in the LA of patients with persistent AF only. Fibrosis, volume, and surface of the RA and LA, but not sphericity, were strongly correlated. Tricuspid regurgitation predicted right atrial volume and shape, whereas diabetes was associated with right atrial fibrosis burden; sex and persistent AF also predicted right atrial volume. Fibrosis in the RA was mostly located in the inferior vena cava-RA junction. Only right atrial sphericity is significantly associated with AF recurrences after ablation (hazard ratio, 1.12 [95% CI, 1.01-1.25]). Conclusions AF progression associates with right atrial remodeling in parallel with the LA. Right atrial sphericity yields prognostic significance after ablation.

Proximity to the descending aorta predicts regional fibrosis in the adjacent left atrial wall: aetiopathogenic and prognostic implications.

AIMS: Left atrial (LA) fibrosis is present in patients with atrial fibrillation (AF) and can be visualized by magnetic resonance imaging with late gadolinium enhancement (LGE-MRI). Previous studies have shown that LA fibrosis is not randomly distributed, being more frequent in the area adjacent to the descending aorta (DAo). The objective of this study is to analyse the relationship between fibrosis in the atrial area adjacent to the DAo and the distance to it, as well as the prognostic implications of this fibrosis. METHODS AND RESULTS: Magnetic resonance imaging with late gadolinium enhancement was obtained in 108 patients before AF ablation to analyse the extent of LA fibrosis and the distance DAo-to-LA. A high-density electroanatomic map was performed in a subgroup of 16 patients to exclude the possibility of an MRI artifact. Recurrences after ablation were analysed at 1 year of follow-up. The extent of atrial fibrosis in the area adjacent to the DAo was inversely correlated with the distance DAo-to-LA (r = -0.34, P < 0.001). This area had the greatest intensity of LGE [image intensity ratio (IIR) 1.14 ± 0.15 vs. 0.99 ± 0.16; P < 0.001] and also the lowest voltage (1.07 ± 0.86 vs. 1.54 ± 1.07 mV; P < 0.001) and conduction velocity (0.65 ± 0.06 vs. 0.96 ± 0.57 mm/ms; P < 0.001). The extent of this regional fibrosis predicted recurrence after AF ablation [hazard ratio (HR) 1.02, 95% CI 1.01-1.03; P = 0.01], however total fibrosis did not (HR = 1.01, 95% CI 0.97-1.06, P = 0.54). CONCLUSIONS: Atrial fibrosis was predominantly located in the area adjacent to the DAo, and increased with the proximity between the two structures. Furthermore, this regional fibrosis better predicted recurrence after AF ablation than total atrial fibrosis.

Accuracy of left atrial fibrosis detection with cardiac magnetic resonance: correlation of late gadolinium enhancement with endocardial voltage and conduction velocity.

AIMS: Myocardial fibrosis is a hallmark of atrial fibrillation (AF) and its characterization could be used to guide ablation procedures. Late gadolinium enhanced-magnetic resonance imaging (LGE-MRI) detects areas of atrial fibrosis. However, its accuracy remains controversial. We aimed to analyse the accuracy of LGE-MRI to identify left atrial (LA) arrhythmogenic substrate by analysing voltage and conduction velocity at the areas of LGE. METHODS AND RESULTS: Late gadolinium enhanced-magnetic resonance imaging was performed before ablation in 16 patients. Atrial wall intensity was normalized to blood pool and classified as healthy, interstitial fibrosis, and dense scar tissue depending of the resulting image intensity ratio. Bipolar voltage and local conduction velocity were measured in LA with high-density electroanatomic maps recorded in sinus rhythm and subsequently projected into the LGE-MRI. A semi-automatic, point-by-point correlation was made between LGE-MRI and electroanatomical mapping. Mean bipolar voltage and local velocity progressively decreased from healthy to interstitial fibrosis to scar. There was a significant negative correlation between LGE with voltage (r = -0.39, P < 0.001) and conduction velocity (r = -0.25, P < 0.001). In patients showing dilated atria (LA diameter ≥45 mm) the conduction velocity predictive capacity of LGE-MRI was weaker (r = -0.40 ± 0.09 vs. -0.20 ± 0.13, P = 0.02). CONCLUSIONS: Areas with higher LGE show lower voltage and slower conduction in sinus rhythm. The enhancement intensity correlates with bipolar voltage and conduction velocity in a point-by-point analysis. The performance of LGE-MRI in assessing local velocity might be reduced in patients with dilated atria (LA diameter ≥45).

Impact of cryoballoon applications on lesion gaps detected by magnetic resonance after pulmonary vein isolation.

INTRODUCTION: Ablation with second-generation cryoballoon technology evolves as an effective and safe alternative to radiofrequency for atrial fibrillation ablation procedures. Nevertheless, the optimal freezing strategy remains unknown. Our objective was to identify the procedural cryoablation parameters predicting successful peri-pulmonary vein (PV) lesions by directly analyzing Postablation gaps in late-gadolinium-enhanced cardiac magnetic resonance (LGE-CMR). METHODS AND RESULTS: Forty-nine consecutive patients (196 PVs) undergoing ablation with second-generation cryoballoon at our center were included. The number and duration of cryoballoon application to achieve PV isolation were left to operator discretion. Gap number and length were quantified in all patients with a LGE-CMR performed 3 months postablation. Application time (420 ± 217 seconds), number of applications (2.1 ± 1.2), application time after electrical isolation (311 ± 194 seconds) and minimum temperature (-45.8 ± 6.5°C) were similar in the 4 PVs. Gaps were observed in 148 PVs (76%), averaging 1.3 ± 1 gaps per vein. Gaps were longer and more frequent in the right PVs (91% vs 59% in left PVs, P < .001). Neither the number, total duration of applications, nor postisolation application time predicted relative length or number of gaps. CONCLUSIONS: After successful PV isolation was achieved in patients undergoing cryoablation, increasing the number of applications, the total application time or application time postisolation did not result in a reduction in the number or the relative length of gaps.

Left ventricle non-compaction cardiomyopathy: Different clinical scenarios and magnetic resonance imaging findings / Miocardiopatía no compactada: diferentes escenarios clínicos y hallazgos en cardiorresonancia magnética

Left ventricle non-compaction cardiomyopathy is currently considered as a well-defined individual entity. However, it includes a broad spectrum of clinical, radiological and pathophysiological findings. In this review we describe 3 different scenarios of this entity: an isolated case with severe left ventricle dysfunction, an "associated" case in a patient with previous atrial septum defect and pulmonary stenosis and finally, as a finding in a patient with a transient cerebrovascular ischemic attack. In the 2 last cases, both asymptomatic, morphological criteria of left ventricle non-compaction were found but, ventricular function was normal and cardiac-MRI showed no late gadolinium hyperenhancement. Periodical follow-up and familial screening were recommended. Natural history and prognosis factors of this disease are still not well known. Further and longer series of patients with this diagnosis are needed to completely define radiological criteria, clinical presentation and evolution.

La miocardiopatía no compactada está considerada actualmente como una entidad independiente y bien definida. Sin embargo, presenta un espectro amplio de hallazgos clínicos, radiológicos y fisiopatológicos. En la presente revisión describimos 3 escenarios clínicos diferentes de dicha entidad: un caso con disfunción ventricular severa, un caso como entidad «asociada¼ a una cardiopatía congènita en un pacientes con un defecto del septo interauricular previo y estenosis pulmonar, y finalmente, como un hallazgo casual en un paciente con un accidente cerebrovascular transitorio. En estos 2 últimos casos se encontraron criterios morfológicos de miocardiopatía no compactada con función ventricular normal y sin presencia de realce tardío de gadolinio en el estudio de cardio-RM. En todos ellos se recomendó estudio familiar. La historia natural y el pronóstico de esta anatomía patológica no son todavía del todo conocidos. Series mayores y seguimiento más largos son necesarios para definir completamente los criterios radiológicos, la presentación clínica y la evolución de esta fascinante entidad.

Left ventricle non-compaction cardiomyopathy: different clinical scenarios and magnetic resonance imaging findings.

Left ventricle non-compaction cardiomyopathy is currently considered as a well-defined individual entity. However, it includes a broad spectrum of clinical, radiological and pathophysiological findings. In this review we describe 3 different scenarios of this entity: an isolated case with severe left ventricle dysfunction, an "associated" case in a patient with previous atrial septum defect and pulmonary stenosis and finally, as a finding in a patient with a transient cerebrovascular ischemic attack. In the 2 last cases, both asymptomatic, morphological criteria of left ventricle non-compaction were found but, ventricular function was normal and cardiac-MRI showed no late gadolinium hyperenhancement. Periodical follow-up and familial screening were recommended. Natural history and prognosis factors of this disease are still not well known. Further and longer series of patients with this diagnosis are needed to completely define radiological criteria, clinical presentation and evolution.

Trombosis de arteria central de la retina y fibroelastoma papilar mitral / Central retinal artery thrombosis and mitral papillary fibroelastoma

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