Effect of late gadolinium enhancement on left atrial impairment in myocarditis patients

Cardiovascular magnetic resonance in β-thalassemia major: beyond T2

Β-thalassemia major (TM) patients underwent regular transfusions to prevent complications of chronic anemia. However, these regular transfusions result in progressive iron accumulation in vital organs, including the heart. Myocardial iron overload can lead to cardiac dysfunction and ultimately to heart failure. Diagnosis of cardiac dysfunction in β-TM patients is usually made through clinical examination, electrocardiogram, and echocardiography. Cardiac magnetic resonance (CMR), through the measurement of T2* relaxation time, represents the diagnostic modality of choice for assessing myocardial iron overload and guiding the iron chelation therapy. Despite a tailored chelation therapy reducing myocardial iron overload, heart failure remains the leading cause of morbidity and mortality even in well-treated β-TM patients. Advances in CMR, including myocardial strain, parametric mapping (T1, T2, and extracellular volume), and late gadolinium enhancement (LGE) measurements, have expanded its role in the diagnosis, prognosis, and follow-up of these patients. This review seeks to offer a thorough overview of the potential uses of CMR in β-TM, extending beyond the established role of T2* measurement in guiding chelation therapy. It delves into the emerging applications of new CMR imaging biomarkers that could improve the overall management of β-TM patients.

Left atrial strain in patients with β-thalassemia major: a cross-sectional CMR study

OBJECTIVES

The aim of this cross-sectional study was to investigate the association of left atrial (LA) strain parameters with demographics, clinical data, cardiovascular magnetic resonance (CMR) findings, and cardiac complications (heart failure and arrhythmias) in a cohort of patients with β-thalassemia major (β-TM).

MATERIALS AND METHODS

We considered 264 β-TM patients (133 females, 36.79 ± 11.95 years) consecutively enrolled in the Extension-Myocardial Iron Overload in Thalassemia (E-MIOT) project. Moreover, we included 35 sex- and age-matched healthy controls (14 females, mean age 37.36 ± 17.52 years). Reservoir, conduit, and booster LA functions were analysed by CMR feature tracking using dedicated software.

RESULTS

Compared to the healthy control group, β-TM patients demonstrated lower LA reservoir strain and booster strains, as well as LA reservoir and booster strain rates. However, no differences were found in LA conduit deformation parameters. In β-TM patients, ageing, sex, and left ventricle (LV) volume indexes were independent determinants of LA strain parameters. The number of segments with late gadolinium enhancement (LGE) significantly correlated with all LA strain parameters, with the exception of the LA conduit rate. Patients with cardiac complications exhibited significantly impaired strain parameters compared to patients without cardiac complications.

CONCLUSION

In patients with β-TM, LA strain parameters were impaired compared to control subjects, and they exhibited a significant correlation with the number of LV segments with LGE. Furthermore, patients with cardiac complications had impaired left atrial strain parameters. Clinical relevance statement In patients with β-thalassemia major, left atrial strain parameters were impaired compared to control subjects and emerged as a sensitive marker of cardiac complications, stronger than cardiac iron levels.

KEY POINTS

• Compared to healthy subjects, β-thalassemia major patients demonstrated significantly lower left atrial reservoir strain and booster strains, as well as left atrial reservoir and booster strain rates. • In β-thalassemia major, ageing, sex, and left ventricular volume indexes were independent determinants of left atrial strain parameters, while left atrial strain parameters were not correlated with myocardial iron overload. • An independent association between reduced left atrial strain parameters and a history of cardiac complications was found in β-thalassemia major patients.

Left and right atrioventricular coupling index in patients with beta-thalassemia major

The aim of this cross-sectional study was to investigate the relationship of left atrioventricular coupling index (LACI) and right atrioventricular coupling index (RACI) with demographics, clinical data, cardiovascular magnetic resonance findings, and cardiac complications (heart failure, arrhythmias, and pulmonary hypertension) in a cohort of patients with beta-thalassemia major (β-TM). We evaluated 292 β-TM patients (151 females, 36.72 ± 11.76 years) consecutively enrolled in the Extension-Myocardial Iron Overload in Thalassemia (E-MIOT) project. Moreover, we assessed 32 sex- and age-matched healthy controls (12 females, mean age 40.78 ± 14.35 years). LACI was determined by calculating the ratio of the left atrium end-diastolic volume to the left ventricle end-diastolic volume, while RACI was defined by calculating the ratio of the right atrium end-diastolic volume to the right ventricle end-diastolic volume. Compared to healthy control, β-TM demonstrated increased LACI (22.99 ± 13.58% vs. 16.05 ± 5.28%; p < 0.0001) and RACI (27.84 ± 10.30% vs. 17.06 ± 5.03%; p < 0.0001). Aging, diabetes, splenectomy, and the presence of late gadolinium enhancement (LGE) showed a significant positive association with both LACI and RACI. In stepwise regression analysis, the presence of LGE was found to be an independent predictor of both impaired LACI and RACI (β coefficient = 0.244, p < 0.0001 and β coefficient = 0.218, p = 0.003; respectively). LACI and RACI were not correlated with myocardial iron overload. Patients with cardiac complications had significantly higher LACI and RACI than patients without cardiac complications. In patients with β-TM, LACI and RACI were significantly associated with the presence of LV LGE. In addition, patients with cardiac complications had impaired LACI and RACI.

Atrial and Ventricular Involvement in Acute Myocarditis Patients with Preserved Ejection Fraction: A Single-Center Cardiovascular Magnetic Resonance Study

Cardiac magnetic resonance (CMR) is commonly employed to confirm the diagnosis of acute myocarditis (AM). However, the impact of atrial and ventricular function in AM patients with preserved ejection fraction (EF) deserves further investigation. Therefore, the aim of this study was to explore the incremental diagnostic value of combining atrial and strain functions using CMR in patients with AM and preserved EF. This retrospective study collected CMR scans of 126 consecutive patients with AM (meeting the Lake Louise criteria) and with preserved EF, as well as 52 age- and sex-matched control subjects. Left atrial (LA) and left ventricular (LV) strain functions were assessed using conventional cine-SSFP sequences. In patients with AM and preserved EF, impaired ventricular and atrial strain functions were observed compared to control subjects. These impairments remained significant even in multivariable analysis. The combined model of atrial and ventricular functions proved to be the most effective in distinguishing AM patients with preserved ejection fraction from control subjects, achieving an area under the curve of 0.77 and showing a significant improvement in the likelihood ratio. These findings suggest that a combined analysis of both atrial and ventricular functions may improve the diagnostic accuracy for patients with AM and preserved EF.

Atrial and Ventricular Strain Imaging Using CMR in the Prediction of Ventricular Arrhythmia in Patients with Myocarditis

(1) Objective: Myocarditis can be associated with ventricular arrhythmia (VA), individual non-invasive risk stratification through cardiovascular magnetic resonance (CMR) is of great clinical significance. Our study aimed to explore whether left atrial (LA) and left ventricle (LV) myocardial strain serve as independent predictors of VA in patients with myocarditis. (2) Methods: This retrospective study evaluated CMR scans in 141 consecutive patients diagnosed with myocarditis based on the updated Lake Louise criteria (29 females, mean age 41 ± 20). The primary endpoint was VA; this encompassed ventricular fibrillation, sustained ventricular tachycardia, nonsustained ventricular tachycardia, and frequent premature ventricular complexes. LA and LV strain function were performed on conventional cine SSFP sequences. (3) Results: After a median follow-up time of 23 months (interquartile range (18-30)), 17 patients with acute myocarditis reached the primary endpoint. In the multivariable Cox regression analysis, LA reservoir (hazard ratio [HR] and 95% confidence interval [CI]: 0.93 [0.87-0.99], p = 0.02), LA booster (0.87 95% CI [0.76-0.99], p = 0.04), LV global longitudinal (1.26 95% CI [1.02-1.55], p = 0.03), circumferential (1.37 95% CI [1.08-1.73], p = 0.008), and radial strain (0.89 95% CI [0.80-0.98], p = 0.01) were all independent determinants of VA. Patients with LV global circumferential strain > -13.3% exhibited worse event-free survival compared to those with values ≤ -13.3% (p < 0.0001). (4) Conclusions: LA and LV strain mechanism on CMR are independently associated with VA events in patients with myocarditis, independent to LV ejection fraction, and late gadolinium enhancement location. Incorporating myocardial strain parameters into the management of myocarditis may improve risk stratification.