Contrast - in cardiac magnetic resonance imaging

Apical Sparing of Longitudinal Strain as a Specific Pattern of Myocardial Fibrosis in Patients with Severe Left Ventricular Hypertrophy: A Comparison between Deformation Imaging and Histological Findings

Objectives: This study aimed to investigate the correlation between apical sparing of longitudinal strain (LS), as measured by speckle-tracking echocardiography (STE), and the histological presence of myocardial fibrosis (MF), in patients with hypertrophic obstructive cardiomyopathy (HOCM). Methods: Twenty-seven HOCM patients who underwent elective Morrow procedures +/- aortic valve replacement (AVR) were included. All patients had standard echocardiography, with STE pre- and post-operatively. Intraoperative probes of the interventricular septum were sent for histological analysis. Correlation of different regional LS patterns with the histological findings of MF and with clinical outcome were analyzed. In addition, a logistic regression and ROC analysis were performed. Results: All patients underwent the Morrow procedure for HOCM, with 33.3% also undergoing AVR. A total of 74.1% showed evidence of MF in the histological analysis. Patients with MF had significantly lower GLS than patients without MF (-12.7 ± 2.7% vs. -23.0 ± 5.7%, p < 0.001). The LS in patients with MF was significantly lower at the basal regions of the LV segments and increased significantly towards the apex as compared to the patients without MF (mean basal-strain %: -10.6 ± 2.6 vs. -17.3 ± 4.6, p < 0.001; mean apical strain %: -21.8 ± 4.8 vs. -16.7 ± 5.6, p = 0.032). In the logistic regression, only the GLS remained as an independent predictor of MF with an Odds ratio of 1.07 (95%-CI: 1.05-1.09, p < 0.001). Conclusions: Our study highlights the significant correlation between GLS and MF in HOCM patients. These findings contribute to the growing understanding of MF in HOCM and may inform future approaches to patient management and risk stratification.

An audit of the establishment of a cardiac magnetic resonance imaging service in a public tertiary hospital setting in the Western Cape Province of South Africa

Introduction

cardiovascular magnetic resonance imaging is considered the standard of care for many clinical cardiovascular applications. Magnetic resonance imaging is a scarce resource in sub-Saharan Africa, with a paucity of cardiac magnetic resonance imaging clinical services and research. The aim of this audit was to review the cardiac magnetic resonance imaging service provided at a public tertiary hospital in Cape Town, Western Cape Province, South Africa.

Methods

a retrospective, descriptive audit via quantitative record review of Tygerberg Hospital´s cardiovascular magnetic resonance imaging service was conducted from the inception thereof on 1st April 2015 up to 31st October 2022.

Results

a total of 1,403 cardiovascular magnetic resonance imaging scans met the inclusion criteria. The mean age of the study population was 43 years, and 52% were female. The most common patient comorbidities were modifiable cardiovascular risk factors, including hypertension (22%; n=306), cigarette smoking (9.6%; n=134), diabetes mellitus type II (6.7%; n=94) and dyslipidaemia (4.4%; n=62). Sixty-three percent (n=888) of scans were performed after hours. In 93% of scans, intravenous gadolinium-based contrast agents were administered. Nonischaemic cardiomyopathy dominated the indications (56.7%; n=976) and final diagnosis (42%; n=589). The most common incidental extracardiac finding was hilar or mediastinal lymphadenopathy (6%; n=82).

Conclusion

the recently established, functional cardiovascular magnetic resonance imaging service at Tygerberg Hospital serves a unique patient population with a comparatively differently distributed cardiac disease spectrum, contributing to research diversity.

Evaluating the effectiveness of echocardiographic guidance in diminishing postoperative wound complications for left atrial appendage closure: A clinical retrospective study

Echocardiographic guidance in left atrial appendage (LAA) closure procedures is increasingly recognized for its potential to enhance patient outcomes in atrial fibrillation (AF). This retrospective study assesses its impact on hospital stay duration, readmission rates and surgical site wound complications in 200 AF patients. Divided equally into an echocardiographically guided group (Group E) and a non-guided group (Group N), the analysis focused on detailed patient data encompassing hospital stay, 30-day readmission and wound complications. Findings revealed that Group E experienced a significantly shorter average hospital stay of 3.5 days, compared with 6.5 days in Group N, along with a lower 30-day readmission rate (5% vs. 18% in Group N). Furthermore, Group E showed a considerable reduction in surgical site wound complications, such as infections and hematomas. The study concludes that echocardiographic guidance in LAA closure procedures markedly improves postoperative wound outcomes, underscoring its potential as a standard practice in cardiac surgeries for AF patients. This approach not only optimizes patient safety and postoperative recovery but also enhances healthcare resource utilization.

Quantitative late gadolinium enhancement cardiac magnetic resonance analysis of the relationship between ablation parameter and left atrial tissue lesion following pulmonary vein isolation

Background

The impact of ablation parameters on acute tissue lesion formation after pulmonary vein isolation (PVI) has not been sufficiently evaluated in patients with atrial fibrillation. Radiofrequency ablation lesion can be visualized by late gadolinium enhancement cardiac magnetic resonance (LGE-CMR). We sought to quantitatively analyze the relationship between ablation parameter and tissue lesion following PVI at different segments of pulmonary vein (PV) using LGE-CMR.

Methods

Twenty-one patients with atrial fibrillation who underwent PVI procedure were retrospectively enrolled. All patients underwent LGE-CMR examination within 3 days after radiofrequency ablation. Ablation parameters during PVI were documented, including lesion size index (LSI), force-time integral (FTI), power, contact force, temperature, and time of duration. The ablation point was projected onto 3-dimensional (3D) left atrial shell constructed base on LGE-CMR and corresponding image intensity ratio (IIR) was calculated on the same shell. A tissue lesion point was defined when the LGE-CMR IIR was > 1.2.

Results

In total, 1,759 ablation points were analyzed. The ablation parameters and IIRs for each PV segment were significantly different (P < 0.0001). IIRs corresponding to ablation points at posterior of PV tended to be higher than those at non-posterior of PV when similar ablation parameters were applied during ablation. LSI was a better predictor of tissue lesion existence following PVI than FTI, contact force, power, temperature, and duration time at non-posterior wall of PV. The IIR showed positive correlation with LSI at non-posterior wall of PV (non-posterior of right PV, r = 0.13, P = 0.001, non-posterior of left PV, r = 0.26, P < 0.0001).

Conclusion

When similar ablation parameters were applied during PVI, the posterior wall of PV had more severe tissue lesion than non-posterior wall of PV. Therefore, it was reasonable to decrease ablation energy at posterior wall of PV. Moreover, LSI was a better index to reflect tissue lesion quality following PVI at non-posterior of PV.

Fibrosis in hypertrophic cardiomyopathy: role of novel echo techniques and multi-modality imaging assessment

Hypertrophic cardiomyopathy (HCM) represents one of the primary cardiomyopathies and may lead to heart failure and sudden cardiac death. Among various histologic features of the disease examined, assessment of myocardial fibrosis may offer valuable information, since it may be considered the common nominator for all HCM connected complications. Late gadolinium-enhanced cardiac magnetic resonance (LGE-CMR) has emerged as the reference noninvasive method for visualizing and quantifying myocardial fibrosis in patients with HCM. T1 mapping, a promising new CMR technique, may provide an advantage over conventional LGE-CMR, by permitting a more valid quantification of diffuse fibrosis. On the other hand, echocardiography offers a significantly more portable, affordable, and easily accessible solution for the study of fibrosis. Various echocardiographic techniques ranging from integrated backscatter and contrast-enhanced ultrasound to two- (2D) or three-dimensional (3D) deformation and shear wave imaging may offer new insights into substrate characterization in HCM. The aim of this review is to describe thoroughly all different modalities that may be used in everyday clinical practice for HCM fibrosis evaluation (with special focus on echocardiographic techniques), to concisely present available evidence and to argue in favor of multi-modality imaging application. It is essential to understand that the role of various imaging modalities is not competitive but complementary, since the information provided by each one is necessary to illuminate the complex pathophysiologic pathways of HCM, offering a personalized approach and treatment in every patient.