Cardiac Magnetic Resonance Assessment of Myocardial Fibrosis

Signal intensity coefficient as a detector of aortic stenosis-induced myocardial fibrosis and its correlation to the long term outcome

OBJECTIVE

Despite advanced aortic valve replacement techniques, aortic stenosis (AS)-induced irreversible myocardial fibrosis contributes to poorer outcomes. Therefore, in addition to early diagnosis of AS, detecting myocardial fibrosis is crucial for physicians to determine the timing of surgery. The Signal Intensity Coefficient (SIC) was used to detect subtle myocardial deformation. Hence, we aimed to investigate whether SIC correlated with myocardial dysfunction and fibrosis from both clinical and preclinical perspectives.

METHODS

We collected medical records and echocardiography images, including the SIC of patients who underwent surgical aortic valve replacement (AVR) for AS from 2010 to 2015. The endpoint of the study was mortality. Median follow-up period was 80 months.

RESULTS

Among 109 patients, 15 died due to cardiovascular causes. Although SIC decreased in all patients post-AVR, patients with an SIC ≥0.34 before surgeries presented with a higher probability of cardiovascular death. In contrast, changes in the left ventricular (LV) ejection fraction, LV mass index, and LV volume failed to predict outcomes. Similarly, SIC was obtained in mice undergoing aortic banding and debanding surgery for comparison with the degree of myocardial fibrosis. SIC was continuously elevated after aortic banding and declined gradually after debanding surgery in mice. Debanding surgery indicated the regression of aortic banding-induced myocardial fibrosis.

CONCLUSION

Pre-AVR SIC was associated with the risk of cardiovascular death and reflected the degree of myocardial fibrosis. Further investigations are required to study the clinical application of SIC in patients with AS.

Cardiac phase-resolved late gadolinium enhancement imaging

Late gadolinium enhancement (LGE) with cardiac magnetic resonance (CMR) imaging is the clinical reference for assessment of myocardial scar and focal fibrosis. However, current LGE techniques are confined to imaging of a single cardiac phase, which hampers assessment of scar motility and does not allow cross-comparison between multiple phases. In this work, we investigate a three step approach to obtain cardiac phase-resolved LGE images: (1) Acquisition of cardiac phase-resolved imaging data with varying T₁ weighting. (2) Generation of semi-quantitative T1* maps for each cardiac phase. (3) Synthetization of LGE contrast to obtain functional LGE images. The proposed method is evaluated in phantom imaging, six healthy subjects at 3T and 20 patients at 1.5T. Phantom imaging at 3T demonstrates consistent contrast throughout the cardiac cycle with a coefficient of variation of 2.55 ± 0.42%. In-vivo results show reliable LGE contrast with thorough suppression of the myocardial tissue is healthy subjects. The contrast between blood and myocardium showed moderate variation throughout the cardiac cycle in healthy subjects (coefficient of variation 18.2 ± 3.51%). Images were acquired at 40–60 ms and 80 ms temporal resolution, at 3T and 1.5, respectively. Functional LGE images acquired in patients with myocardial scar visualized scar tissue throughout the cardiac cycle, albeit at noticeably lower imaging resolution and noise resilience than the reference technique. The proposed technique bears the promise of integrating the advantages of phase-resolved CMR with LGE imaging, but further improvements in the acquisition quality are warranted for clinical use.

Fragmented QRS complexes are associated with subclinical left ventricular dysfunction in patients with Behcet's disease: Four-dimensional speckle tracking echocardiography

BACKGROUND

Behcet's disease (BD) is a chronic systemic inflammatory disease in which early detection of cardiac involvement is essential. The aim of this study was to assess the left ventricular (LV) functions in BD patients using four-dimensional (4D) speckle tracking echocardiography (STE) and to test the correlation between LV dysfunction and the presence of QRS fragmentation.

METHODS

This cross-sectional study included 64 Behcet's patients and 48 healthy volunteers. The BD group was divided into two subgroups depending on the presence (fQRS+) or absence (fQRS-) of fragmented QRS (fQRS). In both groups, left ventricular global area strain (LV-GAS), global radial strain (GRS), global longitudinal strain (GLS), and global circumferential strain (GCS) were obtained with 4D echocardiography.

RESULTS

GAS, GRS, GLS, and GCS values were significantly different in Behcet's patients and in healthy volunteers. GLS and GAS values were lower in the fQRS+ than in the fQRS- group (-15.8 ± 1.8 and -17.9 ± 1.6, P = .001 vs -25.0 ± 3.1 and -29.2 ± 4.2, P < .001, respectively). The duration of disease was longer in fQRS+ than in fQRS- patients (120.8 ± 67.4 vs 71.0 ± 40.5, P < .001). Multiple linear regression analysis showed that fQRS and disease duration were independent predictors of LV-GAS.

CONCLUSIONS

Four-dimensional STE may be helpful for the prediction of early cardiac dysfunction in patients with BD. The presence of fQRS may be an indicator of subclinical LV dysfunction.

Association between fragmented QRS complexes and left-ventricular dysfunction in anabolic androgenic steroid users

Background: Anabolic androgen steroid (AS) use has adverse effects on left ventricular functions, such as fibrosis development. Fragmented QRS is an important marker of myocardial fibrosis, while speckle-tracking echocardiographyis a method used to show subclinical left ventricle dysfunction. In this study, we examined the the ability of fQRS + to detect left ventricle fibrosis by speckle tracking echocardiography (STE) in AS users.Methods: The study included a total of 181 healthy athletes. Athletes were divided into two groups as AS users (n = 89) and non-AS users (n = 92). Then, athletes using AS were divided into two groups as fQRS+ (n = 52) and fQRS- (n = 37). In both groups, the arithmetic mean of three images was used to obtain the left ventricle global longitudinal strain (LV-GLS). The E/SRe ratio was also calculated and analysed.Results: There were significant differences between the AS users and non-AS users in terms of, E/SRe (55.7 ± 17.9 vs 50.3 ± 14.8; p = 0.015), LV-GLS (23.1 ± 1.9 vs 24.0 ± 1.7; p = 0.001), and fQRS (18.5% vs 6%; p = 0.005). When subgroup analysis was performed, both LV-GLS and E/SRivr were found to be poor in the fQRS + group. When multiple linear regression analysis was performed, we determined fQRS as an independent predictor for LV-GLS and E/SRivr ratio.Conclusion: In conclusion, our study demonstrated that fQRS is a parameter that can beused to determine left ventricle subclinical systolic and diastolic dysfunction in AS users. It can be used for cessation of drug use, especially in long-term use.

Fragmented QRS and subclinical left ventricular dysfunction in individuals with preserved ejection fraction: A speckle-tracking echocardiographic study

INTRODUCTION

Fragmented QRS (fQRS) complex on routine 12-lead electrocardiogram (ECG) predicts adverse outcomes in patients with cardiovascular diseases. In addition, it has been found to be associated with subclinical myocardial dysfunction in chronic diseases. We sought to investigate the relationship between the presence of fQRS with the myocardial functions in individuals free from known systemic cardiovascular diseases.

METHODS

In a case-control study, we evaluated normal individuals from March 2017 to February 2018. All participants underwent a 2-dimensional transthoracic echocardiographic examination using tissue Doppler imaging (TDI) and speckle-tracking echocardiography. In addition, all participants were examined using a 12-lead surface ECG, and patients with fQRS and a group of age- and sex-matched controls without fQRS were enrolled in our study.

RESULTS

The patients' mean age was 40.3 ± 10.7 and 35.4 ± 11.2 years in fQRS-positive and fQRS-negative groups, respectively (P = .110). Patients with fQRS had significantly lower values of apical left ventricular global longitudinal strain (LV GLS) in 2-chamber (16.9 ± 2.5 vs. 20.5 ± 3.3, P < .001), 4-chamber (16.9 ± 3.4 vs. 20.1 ± 3, P = .001), LAX views (17.7 ± 2.8 vs. 20.8 ± 3.5, P = .001), and averaged LV GLS (17 ± 2.6 vs. 20.4 ± 2.7, P < .001) values compared to patients without fQRS. In a multivariate analysis, averaged LV GLS and smoking history were independent predictors for positive fQRS.

CONCLUSION

The presence of fQRS on 12-lead ECG in healthy population was associated with lower values of LV GLS compared to normal individuals without fQRS.

Relationship between fragmented QRS complexes and ejection fraction recovery in anterior ST-segment elevation myocardial infarction patients undergoing thrombolytic treatment

BACKGROUND

Acute anterior ST-segment elevation myocardial infarction (STEMI) is a life-threatening disease. Adverse cardiac events of acute anterior STEMI include cardiovascular death or worsening congestive heart failure. This study investigated the role of fragmented QRS complex (fQRS) in predicting insufficient ejection fraction (EF) recovery in acute anterior STEMI.

METHODS

Patients with acute anterior STEMI who received thrombolytic therapy were prospectively enrolled in this study. Twelve-lead electrocardiography (ECG) was obtained from all patients during admission and 24 and 48 h after admission. We divided the patients into two groups according to the presence of fQRS appearance within 48 h: absence of fQRS in any lead (fQRS-), and its presence in two or more contiguous leads (fQRS+). All patients were evaluated with transthoracic echocardiography at admission, and at follow-up 6 and 12 months later.

RESULTS

A total of 138 consecutive patients were included in the study. Seventy-three patients (52.9%) had fQRS in the ECG. EF recovery in the fQRS(+) group was significantly lower than that of the fQRS(-) group (39% vs. 43.9%, P < 0.001). Multiple logistic regression analysis showed that the fQRS (odds ratio: 4.147, 95% confidence interval: 1.607-10.697, P = 0.003) were an independent predictor of poor EF recovery.

CONCLUSION

The presence of fQRS is an independent predictor for inadequate EF recovery in acute anterior STEMI patients undergoing thrombolytic treatment. Assessment of fQRS on surface ECG may be used in determining high-risk patients for poor EF recovery after acute anterior STEMI.

Association between fragmented QRS complexes and left ventricular dysfunction in healthy smokers

OBJECTIVE

Smoking is a known risk factor for cardiovascular diseases and may cause myocardial damage independently of coronary artery disease. Fragmented QRS (fQRS) is an important marker of myocardial fibrosis, while speckle-tracking echocardiography is a method used to show subclinical left ventricle dysfunction.

METHODS

Our study included 230 healthy individuals aged 18-40 years. The patients included were separated into two groups: those smokers (n = 130) and non-smokers (n = 100). After that healthy smokers group were divided into two groups: those with fQRS (n = 24) and those without (n = 106). In both groups, the arithmetic mean of three images was used to obtain the left ventricle global longitudinal strain (LV-GLS). The E/SRe ratio was also calculated and analyzed.

RESULTS

There were significant differences between the smokers and non-smokers in terms of, E/SRe (55.7 ± 17.9 vs 50.3 ± 14.8; P = 0.015), LV-GLS (23.1 ± 1.9 vs 24.0 ± 1.7; P = 0.001), and fQRS (18.5% vs 6%; P = 0.005). As a result of subgroup analysis, pack-year history was higher in the fQRS positive group (16.7 ± 3.7 vs 11.2 ± 3.7, P < 0.001). While a negative correlation was observed between pack-year history and LV-GLS (r = -0.678, P < 0.001), there was a positive correlation between pack-year history and E/SRe (r = 0.730, P < 0.001).

CONCLUSION

In conclusion, our study demonstrated that fQRS is a parameter that can be used to determine left ventricle subclinical systolic and diastolic dysfunction in smokers, and that left ventricle dysfunction is related to the duration and intensity of smoking.

Fragmented QRS complexes are associated with left ventricular dysfunction in patients with type-2 diabetes mellitus: a two-dimensional speckle tracking echocardiography study

Background: Heart failure may develop independently of coronary artery disease in diabetes mellitus (DM) patients. Fragmented QRS (fQRS) is a marker of myocardial fibrosis or scar tissue and is related to an increase in cardiovascular adverse events. In this study, we examined the utility of speckle tracking echocardiography (STE) in assessing LV function in DM patients with fQRS. Methods and Results: The current study included 178 consecutive patients diagnosed with type-2 DM. The patients included were separated into two groups: those with (n = 50) and without (n = 128) fQRS. The two groups were compared by obtaining LV strain values with STE. Statistically significant differences were also identified between fQRS(-) and fQRS (+) groups with respect to Lv-GLS (p < .001), maxLAVI (p = .020), minLAVI (p < .001), E velocity (p < .001), Em velocity (0.002), E/Em ratio (<0.001) SRe (p < .001), SRe/SRa ratio (p < .001), SRivr (p < .001) and E/SRivr ratio (p < .001). In the multiple linear regression analysis, fQRS (β = -2.077, p = .002) and DM duration (β = -0.216, p = .021) were identified as independent predictors of Lv-GLS. However, fQRS (β = 4.557, p = .001) and minLAVI (β = -2.198, p = .031) were also found to be independent predictors of E/SRivr. We also performed multiple logistic regression analysis and identified Lv-GLS (β = -0.557, p = .001), minLAVI (β = -0.769, p = .001), E/Em ratio (β = 0.650, p = .001) and E/SRivr (β = 0.105, p = .001) as independent predictors of fQRS. Conclusıons: The results of this study revealed that subclinical LV dysfunction was more common in diabetic patients with fQRS. Therefore, determination of fQRS could be an indicator of the diabetic CMP in patients with DM.

Association between metabolic syndrome and fragmented QRS complexes: Speckle tracking echocardiography study

BACKGROUND

Metabolic syndrome (MetS) is an endocrinological disease with both metabolic and physiological components. Previous studies have shown a relationship between MetS and left ventricular (LV) dysfunction. A fragmented QRS (fQRS) is a reliable electrocardiogram (ECG) finding with the importance of an indicator of myocardial fibrosis and scarring. In this study, we examined the utility of speckle tracking echocardiography (STE) in assessing LV function in MetS patients with fQRS.

METHODS

The 164 consecutive MetS patients included in the study. They were separated into two groups; those with (n=33) and those without (n=131) fQRS. The two groups were compared by obtaining LV strain values with STE.

RESULTS

Statistically significant differences between the fQRS (-) and fQRS (+) groups were identified for LV global longitudinal strain (LV-GLS) (p<0.001), maximum left atrial volume index (maxLAVI) (p≤0.001), strain rate during isovolumic relaxation period (SRivr) (p<0.001), and the E/SRivr ratio (p<0.001). In the multiple linear regression analysis, fQRS (β=-1.456, p=0.003), diabetes mellitus (β=-0.973, p=0.015), hypertension (β=-0.820, p=0.015) and MaxLAVI (β=-0.142, p=0.018) were independent predictors of LV-GLS. However, fQRS (β=21.995, p<0.001), MaxLAVI (β=3.090, p<0.001), and E/Em ratio (β=3.326, p<0.001) were also independent predictors of E/SRivr.

CONCLUSIONS

The results of this study showed that LV dysfunction was more common in MetS patients with fQRS. MetS patients, and especially those who are fQRS (+), should thus be closely monitored for subclinical LV systolic and diastolic dysfunction.

Role of Cardiac MRI in the Assessment of Cardiomyopathy

OPINION STATEMENT

Combining the diagnostic utilities of cardiac structures, myocardial perfusion, and various tissue characterizing pulse sequence methods in matching scan planes within a single imaging session, cardiac magnetic resonance imaging (CMR) provides a novel interrogation of myocardial physiology and abnormal anatomy from various forms of cardiomyopathy. Establishment of technical imaging standards and clinical adaptation in the past years has helped recognize the distinguishing features of different cardiomyopathies, with CMR currently assuming a pivotal role in the diagnosis of cases of new-onset cardiomyopathy in experienced centers. Quantitative measurements such as ventricular volumes, myocardial iron content, and extent of late gadolinium enhancement can effectively monitor disease status, guide medical therapy, and impact patient outcomes in specific clinical settings. This chapter will aim to summarize these current CMR applications with case examples.

T1 mapping for detection of left ventricular myocardial fibrosis in hypertrophic cardiomyopathy: a preliminary study

PURPOSE

To investigate the diagnostic value of T1 mapping imaging of evaluating fibrosis in patients with hypertrophic cardiomyopathy (HCM).

MATERIALS AND METHODS

21 subjects with HCM and 18 healthy volunteers underwent conventional late gadolinium enhancement (LGE) imaging and T1 mapping imaging. The region of myocardium in HCM is divided into remote area of LGE, peri-LGE, LGE (halo-like LGE and typical patchy LGE). These regions combined with normal volunteers' myocardium were calculated by the reduced percent of T1 value (RPTV).

RESULTS

The RPTV in healthy volunteers was no significant comparing with that in the remote area of LGE in HCM subjects (3.98 ± 3.19 vs. 3.34 ± 2.75, P>0.05). There were significant statistical differences in pairwise among the remote area of LGE, peri-LGE, halo-like LGE and typical patchy LGE in the RPTV (P<0.0001). ROC curves indicated that the T1 mapping imaging has a greater area under the curve comparing with that of traditional LGE imaging (0.975 ± 0.07 vs. 0.753 ± 0.26, P<0.0001).

CONCLUSIONS

HCM has a high prevalence of fibrosis and with varying severity. T1 mapping imaging can be a useful method to evaluate the severity of the fibrosis in HCM.