Predictors of future onset of atrial fibrillation in hypertrophic cardiomyopathy.

BACKGROUND: Novel predictors of atrial fibrillation (AF) in hypertrophic cardiomyopathy (HCM) are desirable. AIM: To detect new multimodality imaging variables predictive of de novo AF in HCM. METHODS: Consecutive patients with HCM underwent clinical assessment and 48-hour Holter electrocardiography to detect AF episodes. Left ventricular (LV) morphology, function and fibrosis, and the left atrium (LA) were characterized by cardiac magnetic resonance. Mitral valve, systolic pulmonary artery pressure, LV filling and maximum gradients were assessed by echocardiography. Patients with no previous history of AF were followed with Holter recordings. RESULTS: Two hundred and nine patients were included (mean age 53±16 years; 140 men), 46 (22%) of whom had a history of AF and a longer duration from HCM diagnosis, more frequent use of heart failure medication, a higher systolic pulmonary artery pressure, a lower LV ejection fraction, a higher extent of LV fibrosis and prevalence of fibrosis on right ventricular (RV)-LV insertions, a higher LA volume and lower LA phasic function. Patients with no AF at inclusion were followed for 26 (17-42) months, and 15 (9%) developed de novo AF. Among clinical characteristics, New York Heart Association class was the only significant AF predictor in the multivariable analysis (hazard ratio 2.65 per class, 95% confidence interval [CI] 1.15-6.10; P=0.02). Among imaging characteristics, two independent predictors were identified: myocardial fibrosis on RV insertions (hazard ratio 2.8, 95% CI 1.3-5.9; P=0.008); and LA volume (hazard ratio 1.03 per mL/m2, 95% CI 1.01-1.06; P=0.006). CONCLUSIONS: AF in HCM is predicted by New York Heart Association class, LA volume and LV fibrosis on RV-LV insertions on cardiac magnetic resonance imaging. The mechanisms relating the ventricular phenotype to AF should be clarified in future studies.

High-resolution three-dimensional late gadolinium-enhanced cardiac magnetic resonance imaging to identify the underlying substrate of ventricular arrhythmia.

Aims: Cardiac magnetic resonance (CMR) is recommended as a second-line method to diagnose ventricular arrhythmia (VA) substrate. We assessed the diagnostic yield of CMR including high-resolution late gadolinium-enhanced (LGE) imaging. Methods and results: Consecutive patients with sustained ventricular tachycardia (VT), non-sustained VT (NSVT), or ventricular fibrillation/aborted sudden death (VF/SCD) underwent a non-CMR diagnostic workup according to current guidelines, and CMR including LGE imaging with both a conventional breath-held and a free-breathing method enabling higher spatial resolution (HR-LGE). The diagnostic yield of CMR was compared with the non-CMR workup, including the incremental value of HR-LGE. A total of 157 patients were enrolled [age 54 ± 17 years; 75% males; 88 (56%) sustained VT, 52 (33%) NSVT, 17 (11%) VF/SCD]. Of these, 112 (71%) patients had no history of structural heart disease (SHD). All patients underwent electrocardiography and echocardiography, 72% coronary angiography, and 51% exercise testing. Pre-CMR diagnoses were 84 (54%) no SHD, 39 (25%) ischaemic cardiomyopathy (ICM), 11 (7%) non-ischaemic cardiomyopathy (NICM), 3 (2%) arrhythmogenic right ventricular cardiomyopathy (ARVC), 2 (1%) hypertrophic cardiomyopathy (HCM), and 18 (11%) other. CMR modified these diagnoses in 48 patients (31% of all and 43% of those with no SHD history). New diagnoses were 9 ICM, 28 NICM, 8 ARVC, 1 HCM, and 2 other. CMR modified therapy in 19 (12%) patients. In patients with no SHD after non-CMR tests, SHD was found in 32 of 84 (38%) patients. Eighteen of these patients showed positive HR-LGE and negative conventional LGE. Thus, HR-LGE significantly increased the CMR detection of SHD (17-38%, P < 0.001). Conclusion: CMR including HR-LGE imaging has high diagnostic value in patients with VAs. This has major prognostic and therapeutic implications, particularly in patients with negative pre-CMR workup.

Lung morphology assessment of cystic fibrosis using MRI with ultra-short echo time at submillimeter spatial resolution.

OBJECTIVES: We hypothesized that non-contrast-enhanced PETRA (pointwise encoding time reduction with radial acquisition) MR (magnetic resonance) sequencing could be an alternative to unenhanced computed tomography (CT) in assessing cystic fibrosis (CF) lung structural alterations, as well as compared agreements and concordances with those of conventional T1-weighted and T2-weighted sequences. MATERIAL AND METHODS: Thirty consecutive CF patients completed both CT and MRI the same day. No contrast injection was used. Agreement in identifying structural alterations was evaluated at the segmental level using a kappa test. Intraclass correlation coefficients (ICC) and Bland-Altman analysis were used to assess concordances and reproducibility in Helbich-Bhalla disease severity scoring. RESULTS: Agreement between PETRA and CT was higher than that of T1- or T2-weighted sequences, notably in assessing the segmental presence of bronchiectasis (Kappa = 0.83; 0.51; 0.49, respectively). The concordance in Helbich-Bhalla scores was very good using PETRA (ICC = 0.97), independently from its magnitude (mean difference (MD) = -0.3 [-2.8; 2.2]), whereas scoring was underestimated using both conventional T1 and T2 sequences (MD = -3.6 [-7.4; 0.1]) and MD = -4.6 [-8.2; -1.0], respectively). Intra- and interobserver reproducibility were very good for all imaging modalities (ICC = 0.86-0.98). CONCLUSION: PETRA showed higher agreement in describing CF lung morphological changes than that of conventional sequences, whereas the Helbich-Bhalla scoring matched closely with that of CT. KEY POINTS: • Spatial resolution of lung MRI is limited using non-ultra-short TE MRI technique • Ultra-short echo time (UTE) technique enables submillimeter 3D-MRI of airways • 3D-UTE MRI shows very good concordance with CT in assessing cystic fibrosis • Radiation-free 3D-UTE MRI enables the Helbich-Bhalla scoring without a need for contrast injection.