Atrial mechanics and their prognostic impact in Takotsubo syndrome: a cardiovascular magnetic resonance imaging study

Atrial and ventricular strain using cardiovascular magnetic resonance in the prediction of outcomes of pericarditis patients: a pilot study

OBJECTIVE

Our study aimed to explore with cardiovascular magnetic resonance (CMR) the impact of left atrial (LA) and left ventricular (LV) myocardial strain in patients with acute pericarditis and to investigate their possible prognostic significance in adverse outcomes.

METHOD

This retrospective study performed CMR scans in 36 consecutive patients with acute pericarditis (24 males, age 52 [23-52]). The primary endpoint was the combination of recurrent pericarditis, constrictive pericarditis, and surgery for pericardial diseases defined as pericardial events. Atrial and ventricular strain function were performed on conventional cine SSFP sequences.

RESULTS

After a median follow-up time of 16 months (interquartile range [13-24]), 12 patients with acute pericarditis reached the primary endpoint. In multivariable Cox regression analysis, LA reservoir and LA conduit strain parameters were all independent determinants of adverse pericardial diseases. Conversely, LV myocardial strain parameters did not remain an independent predictor of outcome. With receiving operating characteristics curve analysis, LA conduit and reservoir strain showed excellent predictive performance (area under the curve of 0.914 and 0.895, respectively) for outcome prediction at 12 months.

CONCLUSION

LA reservoir and conduit mechanisms on CMR are independently associated with a higher risk of adverse pericardial events. Including atrial strain parameters in the management of acute pericarditis may improve risk stratification.

CLINICAL RELEVANCE STATEMENT

Atrial strain could be a suitable non-invasive and non-contrast cardiovascular magnetic resonance parameter for predicting adverse pericardial complications in patients with acute pericarditis.

KEY POINTS

• Myocardial strain is a well-validated CMR parameter for risk stratification in cardiovascular diseases. • LA reservoir and conduit functions are significantly associated with adverse pericardial events. • Atrial strain may serve as an additional non-contrast CMR parameter for stratifying patients with acute pericarditis.

Prognostic role of cardiovascular magnetic resonance in Takotsubo syndrome: A systematic review

BACKGROUND

Takotsubo syndrome (TS) is characterized by transient myocardial dysfunction with outcomes ranging from favorable to life-threatening. Cardiovascular magnetic resonance (CMR) has emerged as an essential tool in its diagnosis and management and is consistently recommended by current guidelines in the diagnostic work-up. However, the prognostic value of CMR in patients with TS remains undetermined. The aim of this study was to assess the prognostic value of CMR in managing patients with TS.

METHOD

PubMed, MEDLINE via Ovid, Scopus, and the Cochrane Library were searched to identify studies reporting the prognostic role of multiparameteric CMR in patients with TS with a follow-up ≥ 12 months. The primary endpoint was major adverse cardiovascular and cerebrovascular events (MACCE), defined as all-cause mortality, cardiac death, heart failure, sudden cardiac death, recurrence of TS, and cerebrovascular events.

RESULTS

Five studies with 564 patients were included for reporting correlation of CMR parameters with MACCE. Primary endpoint occurred in 69 (12%) patients. Among the CMR parameters assessed, myocardial strain parameters (including measurements of the left atrium, left and right ventricle), right ventricle involvement, and a CMR-based radiomics model demonstrated correlations with MACCE. Additionally, one study showed the predictive ability of a CMR score.

CONCLUSION

The current systematic review suggests that CMR may offer prognostic insights in TS patients, underscoring its potential clinical utility for integration into clinical practice. However, scarce data are currently available; hence, further research is needed.

Life-Threatening Arrhythmias in Patients With Takotsubo Syndrome: Insights Into Pathophysiology and Treatment Innovations

Takotsubo syndrome (TTS) is a reversible form of acute myocardial injury due to a neurocardiogenic mechanism associated with a relevant risk for life-threatening ventricular arrhythmias, occurring in up to 25% of all patients and including both ventricular arrhythmias (especially) in the context of QT prolongation and atrial tachy- or bradyarrhythmias. The pathogenetic mechanisms of TTS-related arrhythmic complications are not completely understood, and there are no randomized clinical trials addressing the pharmacologic and nonpharmacologic management in this specific setting. In this narrative review, the authors provide an overview of the pathogenesis and the therapeutic management of arrhythmic complications in patients with TTS, along with the future perspectives and the remaining knowledge gaps in this field.

CMR-based cardiac phenotyping in different forms of heart failure

Heart failure (HF) is a heterogenous disease requiring precise diagnostics and knowledge of pathophysiological processes. Since structural and functional imaging data are scarce we hypothesized that cardiac magnetic resonance (CMR)-based analyses would provide accurate characterization and mechanistic insights into different HF groups comprising preserved (HFpEF), mid-range (HFmrEF) and reduced ejection fraction (HFrEF). 22 HFpEF, 17 HFmrEF and 15 HFrEF patients as well as 19 healthy volunteers were included. CMR image assessment contained left atrial (LA) and left ventricular (LV) volumetric evaluation as well as left atrioventricular coupling index (LACI). Furthermore, CMR feature-tracking included LV and LA strain in terms of reservoir (Es), conduit (Ee) and active boosterpump (Ea) function. CMR-based tissue characterization comprised T1 mapping as well as late-gadolinium enhancement (LGE) analyses. HFpEF patients showed predominant atrial impairment (Es 20.8%vs.25.4%, p = 0.02 and Ee 8.3%vs.13.5%, p = 0.001) and increased LACI compared to healthy controls (14.5%vs.23.3%, p = 0.004). Patients with HFmrEF showed LV enlargement but mostly preserved LA function with a compensatory increase in LA boosterpump (LA Ea: 15.0%, p = 0.049). In HFrEF LA and LV functional impairment was documented (Es: 14.2%, Ee: 5.4% p < 0.001 respectively; Ea: 8.8%, p = 0.02). This was paralleled by non-invasively assessed progressive fibrosis (T1 mapping and LGE; HFrEF > HFmrEF > HFpEF). CMR-imaging reveals insights into HF phenotypes with mainly atrial affection in HFpEF, ventricular affection with atrial compensation in HFmrEF and global impairment in HFrEF paralleled by progressive LV fibrosis. These data suggest a necessity for a personalized HF management based on imaging findings for future optimized patient management.

Real-time cardiovascular magnetic resonance imaging for non-invasive characterisation of heart failure with preserved ejection fraction: final outcomes of the HFpEF stress trial

BACKGROUND

The diagnosis of heart failure with preserved ejection fraction (HFpEF) remains challenging. Recently, the HFpEF Stress Trial demonstrated feasibility and accuracy of non-invasive cardiovascular magnetic resonance (CMR) real-time (RT) exercise-stress atrial function imaging for early identification of HFpEF. However, no outcome data have yet been presented.

METHODS

The HFpEF Stress Trial (DZHK-17) prospectively recruited 75 patients with dyspnea on exertion and echocardiographic preserved EF and signs of diastolic dysfunction (E/e' > 8). 68 patients entered the final study cohort and were characterized as HFpEF (n = 34) or non-cardiac dyspnea (n = 34) according to pulmonary capillary wedge pressure (HFpEF: PCWP rest: ≥ 15 mmHg stress: ≥ 25 mmHg). These patients were contacted by telephone and hospital charts were reviewed. The clinical endpoint was cardiovascular events (CVE).

RESULTS

Follow-up was performed after 48 months; 1 patient was lost to follow-up. HFpEF patients were more frequently compared to non-cardiac dyspnea (15 vs. 8, p = 0.059). Hospitalised patients during follow-up had higher H2FPEF scores (5 vs. 3, p < 0.001), and impaired left atrial (LA) function at rest (p ≤ 0.002) and stress (p ≤ 0.006). Impairment of CMR-derived atrial function parameters at rest and during exercise-stress (p ≤ 0.003) was associated with increased likelihood for CVE. CMR-Feature Tracking LA Es/Ee (p = 0.016/0.017) and RT-CMR derived LA long axis strain (p = 0.003) were predictors of CVE independent of the presence of atrial fibrillation.

CONCLUSIONS

Left atrial function emerged as the strongest predictor for 4-year outcome in the HFpEF Stress Trial. A combination of rest and exercise-stress LA function quantification allows accurate diagnostic and prognostic stratification in HFpEF.

CLINICALTRIALS

gov: NCT03260621.

Takotsubo syndrome: left atrial and ventricular myocardial strain impairment in the subacute and convalescent phases assessed by CMR

BACKGROUND

We investigated the differences in impairment of left ventricle (LV) and left atrium (LA) contractile dysfunction between subacute and convalescent takotsubo syndrome (TTS), using myocardial strain analysis by cardiac magnetic resonance (CMR) feature-tracking technique.

METHODS

We retrospectively selected 50 patients with TTS clinical-radiological diagnosis who underwent CMR within 30 days since symptoms onset: 19 studied during the early subacute phase (sTTS, ≤ 7 days) and 31 during the convalescence (cTTS, 8-30 days). We measured the following: LV global longitudinal, circumferential, and radial strain (lvGLS, lvGCS, lvGRS) and strain rate (SR) and LA reservoir (laS_r), conduit (laS_cd), and booster pump strain (laS_bp) and strain rate (laSR_r, laSR_cd, laSR_bp). Patients were compared with 30 age- and sex-matched controls.

RESULTS

All patients were women (mean age 63 years). TTS patients showed altered LV- and LA-strain features, compared to controls. sTTS was associated with increased laS_bp (12.7% versus 9.8%) and reduced lvEF (47.4% versus 54.8%), lvGLS (-12.2% versus 14.6%), and laS_cd (7.0% versus 9.5%) compared to cTTS (p ≤ 0.029). The interval between symptoms onset and CMR was correlated with laS_bp (r = -0.49) and lvGLS (r = 0.47) (p = 0.001 for both). At receiver operating characteristics analysis, laS_bp was the best discriminator between sTTS and cTTS (area under the curve [AUC] 0.815), followed by lvGLS (AUC 0.670).

CONCLUSIONS

LA dysfunction persists during the subacute and convalescence of TTS. laS_bp increases in subacute phase with progressive decrease during convalescence, representing a compensatory mechanism of LV dysfunction and thus a useful index of functional recovery.

RELEVANCE STATEMENT

Atrial strain has the potential to enhance the delineation of cardiac injury and functional impairment in TTS patients, assisting in the identification of individuals at higher risk and facilitating the implementation of more targeted and personalized medical therapies.

KEY POINTS

• In TTS, after ventricular recovery, atrial dysfunction persists assessable with CMR feature tracking. • Quantitative assessment of atrial strain discriminates atrial functions: reservoir, conduit, and booster pump. • Atrial booster pump changes after acute TTS, regardless of ventricular function. • Atrial strain may serve as a temporal marker in TTS.

Impact of temporal and spatial resolution on atrial feature tracking cardiovascular magnetic resonance imaging

BACKGROUND

Myocardial deformation assessment by cardiovascular magnetic resonance-feature tracking (CMR-FT) has incremental prognostic value over volumetric analyses. Recently, atrial functional analyses have come to the fore. However, to date recommendations for optimal resolution parameters for accurate atrial functional analyses are still lacking.

METHODS

CMR-FT was performed in 12 healthy volunteers and 9 ischemic heart failure (HF) patients. Cine sequences were acquired using different temporal (20, 30, 40 and 50 frames/cardiac cycle) and spatial resolution parameters (high 1.5 × 1.5 mm in plane and 5 mm slice thickness, standard 1.8 × 1.8 × 8 mm and low 3.0 × 3.0 × 10 mm). Inter- and intra-observer reproducibility were calculated.

RESULTS

Increasing temporal resolution is associated with higher absolute strain and strain rate (SR) values. Significant changes in strain assessment for left atrial (LA) total strain occurred between 20 and 30 frames/cycle amounting to 2,5-4,4% in absolute changes depending on spatial resolution settings. From 30 frames/cycle onward, absolute strain values remained unchanged. Significant changes of LA strain rate assessment were observed up to the highest temporal resolution of 50 frames/cycle. Effects of spatial resolution on strain assessment were smaller. For LA total strain a general trend emerged for a mild decrease in strain values obtained comparing the lowest to the highest spatial resolution at temporal resolutions of 20, 40 and 50 frames/cycle (p = 0.006-0.046) but not at 30 frames/cycle (p = 0.140).

CONCLUSION

Temporal and to a smaller extent spatial resolution affect atrial functional assessment. Consistent strain assessment requires a standard spatial resolution and a temporal resolution of 30 frames/cycle, whilst SR assessment requires even higher settings of at least 50 frames/cycle.

Exploring the EVolution in PrognOstic CapabiLity of MUltisequence Cardiac MagneTIc ResOnance in PatieNts Affected by Takotsubo Cardiomyopathy Based on Machine Learning Analysis: Design and Rationale of the EVOLUTION Study

PURPOSE

Takotsubo cardiomyopathy (TTC) is a transient but severe acute myocardial dysfunction with a wide range of outcomes from favorable to life-threatening. The current risk stratification scores of TTC patients do not include cardiac magnetic resonance (CMR) parameters. To date, it is still unknown whether and how clinical, trans-thoracic echocardiography (TTE), and CMR data can be integrated to improve risk stratification.

METHODS

EVOLUTION (Exploring the eVolution in prognOstic capabiLity of mUlti-sequence cardiac magneTIc resOnance in patieNts affected by Takotsubo cardiomyopathy) is a multicenter, international registry of TTC patients who will undergo a clinical, TTE, and CMR evaluation. Clinical data including demographics, risk factors, comorbidities, laboratory values, ECG, and results from TTE and CMR analysis will be collected, and each patient will be followed-up for in-hospital and long-term outcomes. Clinical outcome measures during hospitalization will include cardiovascular death, pulmonary edema, arrhythmias, stroke, or transient ischemic attack.Clinical long-term outcome measures will include cardiovascular death, pulmonary edema, heart failure, arrhythmias, sudden cardiac death, and major adverse cardiac and cerebrovascular events defined as a composite endpoint of death from any cause, myocardial infarction, recurrence of TTC, transient ischemic attack, and stroke. We will develop a comprehensive clinical and imaging score that predicts TTC outcomes and test the value of machine learning models, incorporating clinical and imaging parameters to predict prognosis.

CONCLUSIONS

The main goal of the study is to develop a comprehensive clinical and imaging score, that includes TTE and CMR data, in a large cohort of TTC patients for risk stratification and outcome prediction as a basis for possible changes in patient management.

Machine learning approach in diagnosing Takotsubo cardiomyopathy: The role of the combined evaluation of atrial and ventricular strain, and parametric mapping

BACKGROUND

Cardiac magnetic resonance (CMR) with late gadolinium enhancement (LGE) is a key diagnostic tool in the differential diagnosis between non-ischemic cause of cardiac chest pain. Some patients are not eligible for a gadolinium contrast-enhanced CMR; in this scenario, the diagnosis remains challenging without invasive examination. Our purpose was to derive a machine learning model integrating some non-contrast CMR parameters and demographic factors to identify Takotsubo cardiomyopathy (TTC) in subjects with cardiac chest pain.

MATERIAL AND METHODS

Three groups of patients were retrospectively studied: TTC, acute myocarditis, and healthy controls. Global and regional left ventricular longitudinal, circumferential, and radial strain (RS) analysis included were assessed. Reservoir, conduit, and booster bi-atrial functions were evaluated by tissue-tracking. Parametric mapping values were also assessed in all the patients. Five different tree-based ensemble learning algorithms were tested concerning their ability in recognizing TTC in a fully cross-validated framework.

RESULTS

The CMR-based machine learning (ML) ensemble model, by using the Extremely Randomized Trees algorithm with Elastic Net feature selection, showed a sensitivity of 92% (95% CI 78-100), specificity of 86% (95% CI 80-92) and area under the ROC of 0.94 (95% CI 0.90-0.99) in diagnosing TTC. Among non-contrast CMR parameters, the Shapley additive explanations analysis revealed that left atrial (LA) strain and strain rate were the top imaging markers in identifying TTC patients.

CONCLUSIONS

Our study demonstrated that using a tree-based ensemble learning algorithm on non-contrast CMR parameters and demographic factors enables the identification of subjects with TTC with good diagnostic accuracy.

TRANSLATIONAL OUTLOOK

Our results suggest that non-contrast CMR features can be implemented in a ML model to accurately identify TTC subjects. This model could be a valuable tool for aiding in the diagnosis of subjects with a contraindication to the contrast media. Furthermore, the left atrial conduit strain and strain rate were imaging markers that had a strong impact on TTC identification. Further prospective and longitudinal studies are needed to validate these findings and assess predictive performance in different cohorts, such as those with different ethnicities, and social backgrounds and undergoing different treatments.

The emerging role of atrial strain assessed by cardiac MRI in different cardiovascular settings: an up-to-date review

The left atrium (LA) has a crucial function in maintaining left ventricular filling, which is responsible for about one-third of all cardiac filling. A growing body of evidence shows that LA is involved in several cardiovascular diseases from a clinical and prognostic standpoint. LA enlargement has been recognized as a predictor of the outcomes of many diseases. However, LA enlargement itself does not explain the whole LA's function during the cardiac cycle. For this reason, the recently proposed assessment of atrial strain at advanced cardiac magnetic resonance (CMR) enables the usual limitations of the sole LA volumetric measurement to be overcome. Moreover, the left atrial strain impairment might allow several cardiovascular diseases to be detected at an earlier stage. While traditional CMR has a central role in assessing LA volume and, through cine sequences, a marginal role in evaluating LA function, feature tracking at advanced CMR (CMR-FT) has been increasingly confirmed as a feasible and reproducible technique for assessing LA function through strain. In comparison to atrial function evaluations via speckle tracking echocardiography, CMR-FT has a higher spatial resolution, larger field of view, and better reproducibility. In this literature review on atrial strain analysis, we describe the strengths, limitations, recent applications, and promising developments of studying atrial function using CMR-FT in clinical practice. KEY POINTS: • The left atrium has a crucial function in maintaining left ventricular filling; left atrial size has been recognized as a predictor of the outcomes of many diseases. • Left atrial strain has been confirmed as a marker of atrial functional status and demonstrated to be a sensitive tool in the subclinical phase of a disease. • A comprehensive evaluation of the three phases of atrial function by CMR-FT demonstrates an impairment before the onset of atrial enlargement, thus helping clinicians in their decision-making and improving patient outcomes.

Atrial Impairment as a Marker in Discriminating Between Takotsubo and Acute Myocarditis Using Cardiac Magnetic Resonance

PURPOSE

The purpose of this study was to comprehensively compare the left and right atrium strain and strain rate (SR) parameters by cardiac magnetic resonance (CMR) between patients with Takotsubo (TS) and patients with acute myocarditis (AM).

MATERIALS AND METHODS

We retrospectively enrolled 3 groups of patients: TS (n=18), AM (n=14), and 11 healthy subjects. All the patients had complete CMR data for features tracking assessment.Differences in reservoir, conduit strain (εe), conduit strain rate (SRe), and booster phase of biatrial strain were analyzed between the groups using analysis of variance and multivariate analysis of covariance analyses. Intraobserver and interobserver reproducibility was assessed for all strain and SR parameters using intraclass correlation coefficients and Bland-Altman analysis.

RESULTS

Atrial strain was feasible in all patients and controls. In TS, left atrium (LA) reservoir strain (εs), reservoir SR, εe, and SRe were significantly lower compared with the other groups (P=0,001 for all). multivariate analysis of covariance analysis showed association of these parameters after correction for age and sex, while LA booster deformation (εa and SRa) strain parameters were preserved. LA SRe proved to have excellent sensitivity in differentiating patients with TS from those with AM (areas under the curves of 0.903, 95% confidence interval: 0.81-0.99).Biatrial strain and SR parameters showed good (excellent) intraobserver and interobserver reproducibility (ranged between 0.61 to 0.96 and 0.50 to 0.90, respectively).

CONCLUSION

Compared with AM, patients with TS showed significantly decreased LA reservoir, conduit strain, and SR parameters. Therefore, LA strain assessment may have a role in discriminating between TS and AM.

Sleep-Disordered Breathing Is Associated With Reduced Left Atrial Strain Measured by Cardiac Magnetic Resonance Imaging in Patients After Acute Myocardial Infarction

Aims

Sleep disordered breathing (SDB) is known to cause left atrial (LA) remodeling. However, the relationship between SDB severity and LA dysfunction is insufficiently understood and may be elucidated by detailed feature tracking (FT) strain analysis of cardiac magnetic resonance images (CMR). After myocardial infarction (MI), both the left ventricle and atrium are subjected to increased stress which may be substantially worsened by concomitant SDB that could impair consequential healing. We therefore analyzed atrial strain in patients at the time of acute MI and 3 months after.

Methods and Results

40 patients with acute MI underwent CMR and polysomnography (PSG) within 3–5 days after MI. Follow-up was performed 3 months after acute MI. CMR cine data were analyzed using a dedicated FT software. Atrial strain (ε) and strain rate (SR) for atrial reservoir ([ε_s]; [SR_s]), conduit ([ε_e]; [SR_e]) and booster function ([ε_a]; [SR_a]) were measured in two long-axis views. SDB was defined by an apnea-hypopnea-index (AHI) ≥15/h. Interestingly, LA ε_s and ε_e were significantly reduced in patients with SDB and correlated negative with AHI as a measure of SDB severity at both baseline and follow-up. Intriguingly, patients that exhibited a reduced AHI at follow-up were more likely to have developed improved atrial reservoir and conduit strain (linear regression, p=0.08 for ε_s and ε_e). Patients with improved SDB (ΔAHI < −5/h) exhibited a mean improvement of LA reservoir strain of +7.2 ± 8.4% whereas patients with SDB deterioration (ΔAHI> + 5/h) showed a mean decrease of −5.3 ± 11.0% (p = 0.0131). Similarly, the difference for LA conduit function was +4.8 ± 5.9% (ΔAHI < −5/h) vs −3.6 ± 8.8% (ΔAHI> +5/h). Importantly, conventional volumetric parameters for atrial function (LA area, LA volume index) did not correlate with AHI at baseline or follow-up.

Conclusion

Our results show that LA function measured by CMR strain but not by volumetry is impaired in patients with SDB during acute cardiac injury. Consistent with a mechanistic association, improvement of SBD at follow-up resulted in improved LA strain. LA strain measurement might thus provide insight into atrial function in patients with SDB.

Stepwise approach for diagnosis and management of Takotsubo syndrome with cardiac imaging tools

Takotsubo syndrome is featured by transient left ventricle dysfunction in the absence of significant coronary artery disease, mainly triggered by emotional or physical stress. Its clinical presentation is similar to acute coronary syndrome; therefore, cardiac imaging tools have a crucial role. Coronary angiography is mandatory for exclusion of pathological stenosis. On the other side, transthoracic echocardiography is the first non-invasive imaging modality for an early evaluation of left ventricle systolic and diastolic function. Left ventricle morphologic patterns could be identified according to the localization of wall motion abnormalities. Moreover, an early identification of potential mechanical and electrical complications such as left ventricle outflow tract obstruction, mitral regurgitation, thrombus formation, right ventricular involvement, cardiac rupture, and cardiac rhythm disorders could provide additional information for clinical management and therapy. Because of the dynamic evolution of the syndrome, comprehensive serial echocardiographic examinations should be systematically performed. Advanced techniques, including speckle-tracking echocardiography, cardiac magnetic resonance, and nuclear imaging can provide mechanistic and pathophysiologic insights into this syndrome. This review focuses on these aspects and provide a stepwise approach of all cardiac imaging tools for the diagnosis and the management of Takotsubo syndrome.

Atrial Strain by Feature-Tracking Cardiac Magnetic Resonance Imaging in Takotsubo Cardiomyopathy. Features, Feasibility, and Reproducibility

OBJECTIVES

The purpose of this study was to investigate whether there may be a bi-atrial dysfunction in Takotsubo syndrome (TS) during the transient course of the disease, using cardiac magnetic resonance imaging feature tracking (CMR-FT) in analyzing bi-atrial strain.

METHOD

Eighteen TS patients and 13 healthy controls were studied. Reservoir, conduit, and booster bi-atrial functions were analyzed by CMR-FT. The correlation between LA and RA strain parameters was assessed. Intra- and inter-observer reproducibility was evaluated for all strain and strain rate (SR) parameters using intraclass correlation coefficients (ICCs) and Bland-Altman analysis.

RESULTS

Atrial strain were feasible in all patients and controls. Takotsubo patients showed an impaired LA Reservoir strain (∊_s), LA Reservoir strain rate (SRs), LA and RA Conduit strain(∊_e), LA and RA conduit strain rate (SRe) in comparison with controls (P < 0.001 for all of them), while no differences were found as to LA and RA booster deformation parameters (∊_a and SRa). Analysis of correlation showed that LA ∊_s, SRs, ∊_e, and SRe were positively correlated with corresponding RA strain measurements (P < 0.001, r = 0.61 and P = 0,03, r = 0,54, respectively). Reproducibility was good to excellent for all atrial strain and strain rate parameters (ICCs ranging from 0,50 to 0,96).

CONCLUSION

Atrial strain analysis using CMR-FT may be a useful tool to reveal new pathophysiological insights in Takotsubo cardiomyopathy. Additional studies, with a larger number of patients, are needed to confirm the possible role of these advanced CMR tools in characterizing TS patients.

Novel Imaging and Genetic Risk Markers in Takotsubo Syndrome

Takotsubo syndrome (TTS) is an increasingly recognized condition burdened by significant acute and long-term adverse events. The availability of novel techniques expanded the knowledge on TTS and allowed a more accurate risk-stratification, potentially guiding clinical management. The present review aims to summarize the recent advances in TTS prognostic evaluation with a specific focus on novel imaging and genetic markers. Parametric deformation analysis by speckle-tracking echocardiography, as well as tissue characterization by cardiac magnetic resonance imaging T1 and T2 mapping techniques, currently appear the most clinically valuable applications. Notwithstanding, computed tomography and nuclear imaging studies provided limited but promising data. A genetic predisposition to TTS has been hypothesized, though available evidence is still not sufficient. Although a genetic predisposition appears likely, further studies are needed to fully characterize the genetic background of TTS, in order to identify genetic markers that could assist in predicting disease recurrences and help in familial screening.

Abnormal P-wave terminal force in lead V1 is a marker for atrial electrical dysfunction but not structural remodelling

Aims

There is a lack of diagnostic and therapeutic options for patients with atrial cardiomyopathy and paroxysmal atrial fibrillation. Interestingly, an abnormal P‐wave terminal force in electrocardiogram lead V₁ (PTFV₁) has been associated with atrial cardiomyopathy, but this association is poorly understood. We investigated PTFV₁ as a marker for functional, electrical, and structural atrial remodelling.

Methods and results

Fifty‐six patients with acute myocardial infarction and 13 kidney donors as control cohort prospectively underwent cardiac magnetic resonance imaging to evaluate the association between PTFV₁ and functional remodelling (atrial strain). To further investigate underlying pathomechanisms, right atrial appendage biopsies were collected from 32 patients undergoing elective coronary artery bypass grafting. PTFV₁ was assessed as the product of negative P‐wave amplitude and duration in lead V₁ and defined as abnormal if ≥4000 ms*μV. Activity of cardiac Ca/calmodulin‐dependent protein kinase II (CaMKII) was determined by a specific HDAC4 pull‐down assay as a surrogate for electrical remodelling. Atrial fibrosis was quantified using Masson's trichrome staining as a measure for structural remodelling. Multivariate regression analyses were performed to account for potential confounders. A total of 16/56 (29%) of patients with acute myocardial infarction, 3/13 (23%) of kidney donors, and 15/32 (47%) of patients undergoing coronary artery bypass grafting showed an abnormal PTFV₁. In patients with acute myocardial infarction, left atrial (LA) strain was significantly reduced in the subgroup with an abnormal PTFV₁ (LA reservoir strain: 32.28 ± 12.86% vs. 22.75 ± 13.94%, P = 0.018; LA conduit strain: 18.87 ± 10.34% vs. 10.17 ± 8.26%, P = 0.004). Abnormal PTFV₁ showed a negative correlation with LA conduit strain independent from clinical covariates (coefficient B: −7.336, 95% confidence interval −13.577 to −1.095, P = 0.022). CaMKII activity was significantly increased from (normalized to CaMKII expression) 0.87 ± 0.17 to 1.46 ± 0.15 in patients with an abnormal PTFV₁ (P = 0.047). This increase in patients with an abnormal PTFV₁ was independent from clinical covariates (coefficient B: 0.542, 95% confidence interval 0.057 to 1.027, P = 0.031). Atrial fibrosis was significantly lower with 12.32 ± 1.63% in patients with an abnormal PTFV₁ (vs. 20.50 ± 2.09%, P = 0.006), suggesting PTFV₁ to be a marker for electrical but not structural remodelling.

Conclusions

Abnormal PTFV₁ is an independent predictor for impaired atrial function and for electrical but not for structural remodelling. PTFV₁ may be a promising tool to evaluate patients for atrial cardiomyopathy and for risk of atrial fibrillation.

Quantification of Myocardial Deformation Applying CMR-Feature-Tracking-All About the Left Ventricle?

Purpose of Review

Cardiac magnetic resonance-feature-tracking (CMR-FT)-based deformation analyses are key tools of cardiovascular imaging and applications in heart failure (HF) diagnostics are expanding. In this review, we outline the current range of application with diagnostic and prognostic implications and provide perspectives on future trends of this technique.

Recent Findings

By applying CMR-FT in different cardiovascular diseases, increasing evidence proves CMR-FT-derived parameters as powerful diagnostic and prognostic imaging biomarkers within the HF continuum partly outperforming traditional clinical values like left ventricular ejection fraction. Importantly, HF diagnostics and deformation analyses by CMR-FT are feasible far beyond sole left ventricular performance evaluation underlining the holistic nature and accuracy of this imaging approach.

Summary

As an established and continuously evolving technique with strong prognostic implications, CMR-FT deformation analyses enable comprehensive cardiac performance quantification of all cardiac chambers.

Exercise Stress Real-Time Cardiac Magnetic Resonance Imaging for Noninvasive Characterization of Heart Failure With Preserved Ejection Fraction: The HFpEF-Stress Trial

BACKGROUND

Right heart catheterization using exercise stress is the reference standard for the diagnosis of heart failure with preserved ejection fraction (HFpEF) but carries the risk of the invasive procedure. We hypothesized that real-time cardiac magnetic resonance (RT-CMR) exercise imaging with pathophysiologic data at excellent temporal and spatial resolution may represent a contemporary noninvasive alternative for diagnosing HFpEF.

METHODS

The HFpEF-Stress trial (CMR Exercise Stress Testing in HFpEF; URL: https://www.clinicaltrials.gov; Unique identifier: NCT03260621. URL: https://dzhk.de/; Unique identifier: DZHK-17) prospectively recruited 75 patients with echocardiographic signs of diastolic dysfunction and dyspnea on exertion (E/e'>8, New York Heart Association class ≥II) to undergo echocardiography, right heart catheterization, and RT-CMR at rest and during exercise stress. HFpEF was defined according to pulmonary capillary wedge pressure (≥15 mm Hg at rest or ≥25 mm Hg during exercise stress). RT-CMR functional assessments included time-volume curves for total and early (1/3) diastolic left ventricular filling, left atrial (LA) emptying, and left ventricular/LA long axis strain.

RESULTS

Patients with HFpEF (n=34; median pulmonary capillary wedge pressure at rest, 13 mm Hg; at stress, 27 mm Hg) had higher E/e' (12.5 versus 9.15), NT-proBNP (N-terminal pro-B-type natriuretic peptide; 255 versus 75 ng/L), and LA volume index (43.8 versus 36.2 mL/m²) compared with patients with noncardiac dyspnea (n=34; rest, 8 mm Hg; stress, 18 mm Hg; P≤0.001 for all). Seven patients were excluded because of the presence of non-HFpEF cardiac disease causing dyspnea on imaging. There were no differences in RT-CMR left ventricular total and early diastolic filling at rest and during exercise stress (P≥0.164) between patients with HFpEF and noncardiac dyspnea. RT-CMR revealed significantly impaired LA total and early (P<0.001) diastolic emptying in patients with HFpEF during exercise stress. RT-CMR exercise stress LA long axis strain was independently associated with HFpEF (adjusted odds ratio, 0.657 [95% CI, 0.516-0.838]; P=0.001) after adjustment for clinical and imaging measures and emerged as the best predictor for HFpEF (area under the curve at rest 0.82 versus exercise stress 0.93; P=0.029).

CONCLUSIONS

RT-CMR allows highly accurate identification of HFpEF during physiologic exercise and qualifies as a suitable noninvasive diagnostic alternative. These results will need to be confirmed in multicenter prospective research studies to establish widespread routine clinical use. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03260621. URL: https://dzhk.de/; Unique identifier: DZHK-17.

The year 2019 in the European Heart Journal-Cardiovascular Imaging: Part I

The European Heart Journal-Cardiovascular Imaging was launched in 2012 and has during these years become one of the leading multimodality cardiovascular imaging journals. The journal is now established as one of the top cardiovascular journals and is the most important cardiovascular imaging journal in Europe. The most important studies published in our Journal in 2019 will be highlighted in two reports. Part I of the review will focus on studies about myocardial function and risk prediction, myocardial ischaemia, and emerging techniques in cardiovascular imaging, while Part II will focus on valvular heart disease, heart failure, cardiomyopathies, and congenital heart disease.

An Update on Cardiac Magnetic Resonance Imaging in Takotsubo Cardiomyopathy

Purpose of Review

To provide an update on the use of cardiac magnetic resonance imaging in the diagnosis of Takotsubo cardiomyopathy.

Recent Findings

Long-term prognosis of Takotsubo cardiomyopathy may not be as clear-cut as previously thought. Cardiac magnetic resonance imaging not only allows differentiation between reversible and nonreversible changes but has an emerging role in identifying cellular level changes associated with prognostic indicators such as myocardial energetics using 31P-CMR spectroscopy and detection of myocardial inflammation overlying myocardial oedema, using ultrasmall paramagnetic iron oxide particle uptake in macrophages.

Summary

Takotsubo cardiomyopathy is a non-ischemic acute heart failure syndrome. It is commonly triggered by emotional or physical stress and is possibly the strongest psychosomatic interaction seen in medicine. While clinically its presentation mimics a myocardial infarction, the acute imaging characteristics are critical in correctly identifying the disease entity.

The left atrial function is transiently impaired in Tako-tsubo cardiomyopathy and associated to in-hospital complications: a prospective study using two-dimensional strain

Tako-tsubo cardiomyopathy (TTC) is characterized by the presence of transient left ventricular (LV) dysfunction. Whether left atrial (LA) function is also impaired in this setting is unclear. To assess prospectively LA peak systolic longitudinal strain (LAS) by two-dimensional strain at the acute phase of TTC and after recovery and its association with in-hospital complications. 40 patients with typical TTC (mean age 79.5 ± 10 years) underwent transthoracic-Doppler echocardiography at the acute phase and at follow-up (32 ± 18 days later), including the measurement of the LAS (mean of maximal strain from the 4-2 chamber views). A control group of 15 patients (75 ± 7 years, 13 women) without overt cardiovascular disease served as a comparative group. In-hospital complication was a composite of death, heart failure, cardiogenic shock, LV thrombus, and sustained ventricular arrhythmia. In the TTC group, LAS improved significantly between the two examinations from 15 ± 5.5% to 27 ± 8% (p < 0.01) whereas LA volume did not change (p = NS). In the control group LAS was 30 ± 4% (p < 0.01 vs. TTC acute phase, p = NS vs. TTC follow-up). In TTC, at the acute phase LAS was independently correlated to LV global longitudinal strain (LVGLS), and after recovery to E/e', and the change of LAS was independently correlated to the change of the LVGLS (all, p < 0.01). Furthermore LAS was independently correlated to in-hospital complications (p < 0.01). LA function (reservoir) is transiently impaired in TTC and associated to in-hospital complications. Furthermore, the improvement of LAS parallel the dynamic improvement of LVGLS suggests that TTC induces a transient global left heart dysfunction.