Imaging Features of Arrhythmogenic Cardiomyopathies.

Arrhythmogenic cardiomyopathy (ACM) is a genetic disease characterized by replacement of ventricular myocardium with fibrofatty tissue, predisposing the patient to ventricular arrhythmias and/or sudden cardiac death. Most cases of ACM are associated with pathogenic variants in genes that encode desmosomal proteins, an important cell-to-cell adhesion complex present in both the heart and skin tissue. Although ACM was first described as a disease predominantly of the right ventricle, it is now acknowledged that it can also primarily involve the left ventricle or both ventricles. The original right-dominant phenotype is traditionally diagnosed using the 2010 task force criteria, a multifactorial algorithm divided into major and minor criteria consisting of structural criteria based on two-dimensional echocardiographic, cardiac MRI, or right ventricular angiographic findings; tissue characterization based on endomyocardial biopsy results; repolarization and depolarization abnormalities based on electrocardiographic findings; arrhythmic features; and family history. Shortfalls in the task force criteria due to the modern understanding of the disease have led to development of the Padua criteria, which include updated criteria for diagnosis of the right-dominant phenotype and new criteria for diagnosis of the left-predominant and biventricular phenotypes. In addition to incorporating cardiac MRI findings of ventricular dilatation, systolic dysfunction, and regional wall motion abnormalities, the new Padua criteria emphasize late gadolinium enhancement at cardiac MRI as a key feature in diagnosis and imaging-based tissue characterization. Conditions to consider in the differential diagnosis of the right-dominant phenotype include various other causes of right ventricular dilatation such as left-to-right shunts and variants of normal right ventricular anatomy that can be misinterpreted as abnormalities. The left-dominant phenotype can mimic myocarditis at imaging and clinical examination. Additional considerations for the differential diagnosis of ACM, particularly for the left-dominant phenotype, include sarcoidosis and dilated cardiomyopathy. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Imaging in patients with cardiovascular implantable electronic devices: part 1-imaging before and during device implantation. A clinical consensus statement of the European Association of Cardiovascular Imaging (EACVI) and the European Heart Rhythm Association (EHRA) of the ESC.

More than 500 000 cardiovascular implantable electronic devices (CIEDs) are implanted in the European Society of Cardiology countries each year. The role of cardiovascular imaging in patients being considered for CIED is distinctly different from imaging in CIED recipients. In the former group, imaging can help identify specific or potentially reversible causes of heart block, the underlying tissue characteristics associated with malignant arrhythmias, and the mechanical consequences of conduction delays and can also aid challenging lead placements. On the other hand, cardiovascular imaging is required in CIED recipients for standard indications and to assess the response to device implantation, to diagnose immediate and delayed complications after implantation, and to guide device optimization. The present clinical consensus statement (Part 1) from the European Association of Cardiovascular Imaging, in collaboration with the European Heart Rhythm Association, provides comprehensive, up-to-date, and evidence-based guidance to cardiologists, cardiac imagers, and pacing specialists regarding the use of imaging in patients undergoing implantation of conventional pacemakers, cardioverter defibrillators, and resynchronization therapy devices. The document summarizes the existing evidence regarding the use of imaging in patient selection and during the implantation procedure and also underlines gaps in evidence in the field. The role of imaging after CIED implantation is discussed in the second document (Part 2).

Use of PET/CT to detect myocardial inflammation and the risk of malignant arrhythmia in chronic Chagas disease.

BACKGROUND: Chagas heart disease (CHD) is characterized by progressive myocardial inflammation associated with myocardial fibrosis and segmental abnormalities that may lead to malignant ventricular arrhythmia and sudden cardiac death. This arrhythmia might be related to the persistence of parasitemia or inflammation in the myocardium in late-stage CHD. Positron emission tomography/computed tomography (PET/CT) has been used to detect myocardial inflammation in non-ischemic cardiomyopathies, such as sarcoidosis, and might be useful for risk prediction in patients with CHD. METHODS AND RESULTS: Twenty-four outpatients with chronic CHD were enrolled in this prospective cross-sectional study between May 2019 and March 2022. The patients were divided into two groups: those with sustained ventricular tachycardia and/or aborted sudden cardiac death who required implantable cardioverter-defibrillators, and those with the same stages of CHD and no complex ventricular arrhythmia. Patients underwent 18F-fluorodeoxyglucose (18F-FDG) and 68Ga-DOTATOC PET/CT, and blood samples were collected for qualitative parasite assessment by polymerase chain reaction. Although similar proportions of patients with and without complex ventricular arrhythmia showed 18F-FDG and 68Ga-DOTATOC uptake, 68Ga-DOTATOC corrected SUVmax was higher in patients with complex arrhythmia (3.4 vs 1.7; P = .046), suggesting that inflammation could be associated with the presence of malignant arrhythmia in the late stages of CHD. We also detected Trypanosoma cruzi in both groups, with a nonsignificant trend of increased parasitemia in the group with malignant arrhythmia (66.7% vs 33.3%). CONCLUSION: 18F-FDG and 68Ga-DOTATOC uptake on PET/CT may be useful for the detection of myocardial inflammation in patients with Chagas cardiomyopathy, and 68Ga-DOTATOC uptake may be associated with the presence of malignant arrhythmia, with potential therapeutic implications.

Evaluation of the relationship between speckle tracking echocardiography and arrhythmia markers Tp-e interval and Tp-e/QTc in patients with arterial hypertension.

OBJECTIVE: The prolongation of the Tp-e interval, which is defined as the interval from the peak to the end of the T wave on electrocardiography (ECG), is considered a non-invasive predictor of malignant ventricular arrhythmia development. In our study, we aimed to compare the Tp-e interval and Tp-e/QTc ratios on ECG and subclinical myocardial dysfunction evaluated by left ventricular global longitudinal strain (LV-GLS) imaging in patients receiving treatment for hypertension. PATIENTS AND METHODS: Two-dimensional speckle tracking echocardiography was performed in 102 consecutive hypertensive patients with blood pressure values regulated by treatment. The normal left ventricular global longitudinal strain (LV-GLS) limit was accepted as < -18%. The patients were divided into two groups: those with normal (≥ -18%) LV-GLS and those with impaired LV-GLS (< -18%). Comparisons between the groups were made by measuring ventricular repolarization parameters, such as QT, QTc, and Tp-e intervals, and Tp-e/QT and Tp-e/QTc ratios. RESULTS: While the mean age of the patients with impaired LV-GLS was 55±6 years, the mean age of the normal LV-GLS group was 58±9 years (p=0.101). The Tp-e interval, Tp-e/QT, and Tp-e/QTc ratios were significantly higher in the impaired LV-GLS group than in the normal LV-GLS group (p<0.05 for all). A positive correlation was observed between the ventricular repolarization parameters and LV-GLS values. This positive correlation was statistically significant in terms of the Tp-e interval, Tp-e/QT, and Tp-e/QTc ratios. CONCLUSIONS: The Tp-e interval, Tp-e/QT, and Tp-e/QTc ratios were increased in hypertensive patients with impaired LV-GLS, and therefore a close follow-up in terms of increased arrhythmia risk is required in this patient group.

Fluoroless Catheter Ablation of Left Ventricular Summit Arrhythmias: A Step-by-Step Approach.

Prolonged use of fluoroscopy during catheter ablation (CA) of arrhythmias is associated with a significant exposure to ionizing radiation and risk of orthopedic injuries given the need for heavy protective equipment. CA of ventricular arrhythmias (VAs) arising from the left ventricular (LV) summit is challenging, requiring a vast knowledge of the intricate cardiac anatomy of this area and careful imaging delineation of the different anatomical structures, which is frequently performed using fluoroscopic guidance. Certain techniques, including pericardial mapping and ablation, use of intracoronary wires, and mapping and ablation inside the coronary venous system have been proposed, further prolonging fluoroscopy time. Fluoroless CA procedures are feasible with currently available technology and appear to have similar safety and efficacy outcomes compared with conventional techniques. To successfully perform fluoroless CA of LV summit arrhythmias, it is important to be fully acquainted with intracardiac echocardiography (ICE) imaging and electroanatomic mapping (EAM). We will describe our approach to perform fluoroless CA in LV summit VAs.

Comparison of minimal versus zero-fluoroscopic catheter ablation in gestational supraventricular arrhythmias.

BACKGROUND: The management of symptomatic gestational supraventricular tachycardia (SVT) is challenging and requires a multidisciplinary approach for optimal management. Catheter ablation during pregnancy has traditionally been considered a last option due to procedural safety and ionizing radiation risks. Recent advances including intracardiac echocardiography and multi-electrode electroanatomic mapping have greatly enhanced the safety and efficacy profile to successfully perform ablations with minimal to no fluoroscopy even during pregnancy. This is the first review to compare the efficacy, safety, and aggregate outcomes of purely zero-fluoroscopic and minimal fluoroscopic approaches in gestational SVT. METHODS: A literature search was performed for catheter ablations in the past 15 years for gestational arrhythmias that used minimal or no fluoroscopy. Sixteen cases describing catheter ablations with zero-fluoroscopy were compared to twenty-four cases using minimal fluoroscopy, defined as total documented exposure time of less than 10 min. RESULTS: Analysis of both groups demonstrated that zero-fluoroscopic approaches have comparable efficacy and procedural safety outcomes with the utilization of earlier trimester ablations and in older maternal ages. The utilization of electroanatomic mapping with or without concomitant intracardiac echocardiography in the zero-fluoroscopy group further demonstrated equal efficacy rates of successful ablation when compared to the control group. Furthermore, there were no reported immediate or long-term periprocedural complications in either group, including delivery outcomes. CONCLUSION: Our review demonstrates that zero-fluoroscopy catheter ablation for SVT in pregnancy is both effective and safe when compared to minimal fluoroscopy ablations while eliminating the theoretical risks of ionizing radiation.

Transthoracic echocardiography for arrhythmic mitral valve prolapse: Phenotypic characterization as first step.

Mitral valve prolapse (MVP) is the most frequent valvulopathy with a prevalence of 1.2%-2.4% in general population and it is characterized by a benign course. Although it can be associated with some complications, ventricular arrhythmias (VA) and sudden cardiac death (SCD) as ultimate expressions, are the most worrying. The estimated risk of SCD in MVP is between 0.2% and 1.9% per year including both MVP patients with left ventricular (LV) dysfunction due to severe MR and MVP patients without significant MR. The latter ones constitute a particular phenotype called "malignant MVP" characterized by bileaflet myxomatous prolapse, ECG repolarization abnormalities and complex VAs (c-VAs) with polymorphic/right bundle branch block morphology (RBBB) and LV fibrosis of the papillary muscles (PMs) and inferobasal wall secondary to mechanical stretching visualized as late gadolinium enhancement (LGE) areas by cardiac magnetic resonance (CMR). In MVP, the first diagnostic approach is transthoracic echocardiography (TTE) that defines the presence of mitral annular disjunction (MAD) which seems to be associated with "arrhythmic MVP" (AMVP). From an ECG point of view, AMVP is characterized by frequent premature ventricular contractions (PVCs) arising from one or both PMs, fascicular tissue, and outflow tract, as well as by T-wave inversion in the inferolateral leads. The aim of the present paper is to describe TTE red flags that could identify MVP patients at high risk to develop complex arrhythmias as supported by the corresponding findings of LGE-CMR and anatomy studies. TTE could be a co-partner in phenotyping high-risk arrhythmic MVP patients.

[Clinical characteristics of arrhythmia-onset sarcoidosis cases].

Objective: To describe the clinical characteristics of sarcoidosis patients with arrhythmia as the primary or main manifestation. Methods: We conducted a retrospective analysis of arrhythmia-onset sarcoidosis cases between January 2017 and December 2020. Their clinical manifestations, radiological features, treatment and prognosis were reviewed and analyzed. Results: This study consisted of 3 females and 1 male, with a mean age of 51 years (range from 42 to 58 years old). Arrhythmia was the first or main clinical manifestation for all 4 cases, involving Ⅲ° atrioventricular block (AVB) (n=1), Ⅱ° type Ⅱ AVB (n=1), and frequent ventricular premature beats and short array ventricular tachycardia (n=2). Three cases were diagnosed with respiratory sarcoidosis simultaneously during the diagnostic evaluation for arrhythmia. One case was diagnosed with sarcoidosis because of abnormal chest CT images due to cervical lymph node enlargement 5 years after arrhythmia. All 4 cases were confirmed as presenting epithelioid cell granulomatous inflammation by bronchoscopic biopsies. Late gadolinium enhancement with cardiac magnetic resonance (LGE-CMR) imaging was arranged for two cases. Both of them had typical imaging findings of cardiac sarcoidosis. Three cases were confirmed of cardiac involvement through positron emission computed tomography (PET)-CT. None of the enrolled four cases were arranged with endomyocardial biopsy. All four cases were improved with oral corticosteroids, immunosuppressants and anti-arrhythmic medications. Two cases underwent cardiac pacemaker implantation. Conclusions: The possibility of cardiac sarcoidosis should be considered in middle-aged and elderly patients with unexplained high-degree AVB or ventricular arrhythmia. Chest CT is recommended for routine screening for those cases. LGE-CMR and/or PET-CT is recommended for them to confirm the diagnosis of cardiac sarcoidosis. Corticosteroids and immunosuppressants are effective for these patients.

Aortic Size and Clinical Care Pathways Before Type A Aortic Dissection.

Patients with aortic enlargement are recommended to undergo serial imaging and clinical follow-up until they reach surgical thresholds. This study aimed to identify aortic diameter and care of patients with aortic imaging before aortic dissection (AD). In a retrospective cohort of AD patients, we evaluated previous imaging results in addition to ordering providers and indications. Imaging was stratified as >1 or <1 year: 62 patients (53% men) had aortic imaging before AD (most recent test: 82% echo, 11% computed tomography, 6% magnetic resonance imaging). Imaging was ordered most frequently by primary care physicians (35%) and cardiologists (39%). The most frequent imaging indications were arrhythmia (11%), dyspnea (10%), before or after aortic valve surgery (8%), chest pain (6%), and aneurysm surveillance in 13%. Of all patients, 94% had aortic diameters below the surgical threshold before the AD. Imaging was performed <1 year before AD in 47% and aortic size was 4.4 ± 0.8 cm in ascending aorta and 4.0 ± 0.8 cm in sinus. In patients whose most recent imaging was >1 year before AD (1,317 ± 1,017 days), the mean ascending aortic diameter was 4.2 ± 0.4 cm. In conclusion, in a series of patients with aortic imaging before AD, the aortic size was far short of surgical thresholds in 94% of the group. In >50%, imaging was last performed >1 year before dissection.

Cardiac manifestation is evident in chorea-acanthocytosis but different from McLeod syndrome.

INTRODUCTION: We aimed to study the various cardiac manifestations of the two core neuroacanthocytosis (NA) syndromes, namely chorea-acanthocytosis (ChAc) and McLeod syndrome (MLS). So far, cardiac involvement has been described as specific feature only for MLS. METHODS: We studied six patients with ChAc (mean age 44.5 years, five men, one woman) and six patients with MLS (mean age 57.1 years, all men). Cardiac evaluation included echocardiography and/or cardiac magnetic resonance imaging (cardiac MRI), 24-h ECG-recording and examination of cardiac biomarkers. RESULTS: Cardiac involvement of ChAc was found in four of six patients. Two patients showed mildly reduced left ventricular ejection fraction (LVEF), two other patients mild to moderate left ventricular (LV) dilatation. Neither an increase in ventricular ectopic beats nor ventricular tachycardia were evident in ChAc. Four of five MLS patients showed left ventricle dilatation and reduced left ventricular ejection fraction (LVEF). Two of these, in addition, had critical ventricular tachycardia. High sensitive troponin T was elevated in all patients, for whom data were available (n = 10). In contrast, elevation of high sensitive troponin I was found in one of six ChAc and one of two MLS patients. CONCLUSION: For the first time, we reveal cardiac involvement in a cohort of six ChAc patients, while the risk to develop heart failure seems lower than in MLS. Our study confirms the malignant nature of MLS in terms of ventricular arrhythmias and progression to advanced heart failure. Herein, we define disease-specific recommendations for cardiac assessment in both conditions.

Minimising radiation exposure in catheter ablation of ventricular arrhythmias.

BACKGROUND: Conventional fluoroscopy guided catheter ablation (CA) is an established treatment option for ventricular arrhythmias (VAs). However, with the complex nature of most procedures, patients and staff bare an increased radiation exposure. Near-zero or zero-fluoroscopy CA is an alternative method which could substantially reduce or even eliminate the radiation dose. Our aim was to analyse procedural outcomes with fluoroscopy minimising approach for treatment of VAs in patients with structurally normal hearts (SNH) and structural heart disease (SHD). METHODS: Fifty-two (age 53.4 ± 17.8 years, 38 male, 14 female) consecutive patients who underwent CA of VAs in our institution between May 2018 and December 2019 were included. Procedures were performed primarily with the aid of the three-dimensional electro-anatomical mapping system and intra-cardiac echocardiography. Fluoroscopy was considered only in left ventricular (LV) summit mapping for coronary angiography and when epicardial approach was planned. Acute and long-term procedural outcomes were analysed. RESULTS: Sixty CA procedures were performed. Twenty-five patients had SHD-related VAs (Group 1) and 27 patients had SNH (Group 2). While Group 1 had significantly higher total procedural time (256.9 ± 71.7 vs 123.6 ± 42.2 min; p < 0.001) compared to Group 2, overall procedural success rate [77.4% (24/31) vs 89.7% (26/29); p = 0.20)] and recurrence rate after the first procedure [8/25, (32%) vs 8/27, (29.6%); p = 0.85] were similar in both groups. Fluoroscopy was used in 3 procedures in Group 1 where epicardial approach was needed and in 4 procedures in Group 2 where LV summit VAs were ablated. Overall procedure-related major complication rate was 5%. CONCLUSIONS: Fluoroscopy minimising approach for CA of VAs is feasible and safe in patients with SHD and SNH. Fluoroscopy could not be completely abolished in VAs with epicardial and LV summit substrate location.

Echocardiographic predictors of new-onset atrial arrhythmias in patients undergoing hematopoietic stem cell transplantation.

BACKGROUND: Atrial arrhythmias following hematopoietic stem cell transplantation (HSCT) have been associated with increased length of stay, need for intensive care, and increased mortality within one-year post-transplant. We sought to identify echocardiographic parameters that may predict the development of new atrial arrhythmias post-HSCT. METHODS: We performed a retrospective chart review of 753 consecutive patients who underwent HSCT at the University of Chicago from January 2015 through December 2019. Patients with baseline echocardiogram within 6 months prior to transplantation were included. Those with prior transplants, history of atrial arrhythmias, or unavailable echocardiographic images were excluded, resulting in 187 patients included for final analysis. Baseline clinical and demographic variables, as well as echocardiographic parameters, were compared between patients who developed new atrial arrhythmias post-HSCT versus those who did not. RESULTS: Of the 187 patients included for analysis, 25 (13%) developed new atrial arrhythmias, with 13 of these occurring within 30 days of transplantation. Despite no significant difference in left atrial (LA) end-systolic volume between those with and without new arrhythmia following HSCT (OR 1.04; 95% CI 0.91-1.09, p = 0.233), univariable analysis demonstrated that patients who developed atrial arrhythmias had reduced LA function, as reflected by lower LA emptying fraction (OR 0.94; 95% CI 0.91-0.98, p = 0.003) and lower LA reservoir strain (OR 0.95; 95% CI 0.92-0.99, p = 0.009). CONCLUSIONS: Echocardiographic indices of LA function, namely LA emptying fraction and LA reservoir strain, can identify patients at risk for developing new atrial arrhythmias post-HSCT, prior to the development of morphologic changes in the LA.

Intracardiac Echocardiography to Guide Catheter Ablation of Ventricular Arrhythmias in Ischemic Cardiomyopathy.

Intracardiac echocardiography (ICE) allows intraprocedural assessment of cardiac anatomy and identification of ischemic myocardial scar and is useful for guidance of the ablation catheter and monitoring for complications. In this review, the authors discuss and provide examples of how ICE can be used to obtain additional information to understand arrhythmia mechanisms and facilitate catheter ablation therapy for ventricular arrhythmias arising from ischemic scar substrates.

Intracardiac Echocardiography to Guide Catheter Ablation of Idiopathic Ventricular Arrythmias.

Catheter ablation is the most effective treatment option for idiopathic ventricular arrhythmias. Intracardiac echocardiography (ICE) has been increasingly used during ablation procedures, allowing real-time visualization of cardiac anatomy, and improving our understanding of the relationships between different cardiac structures. In this article we review the adjuvant role of ICE to guide mapping and ablation of ventricular arrhythmias in the structurally normal heart.

Intracardiac Echocardiography to Guide Non-fluoroscopic Electrophysiology Procedures.

Intracardiac echocardiography (ICE) is the most practical method for online imaging during electrophysiological procedures. It allows guiding of complex catheter ablation procedures together with electroanatomical mapping systems, either with minimal or with zero fluoroscopy exposure. Besides safe and reproducible transseptal puncture, ICE helps to assess location and contact of the tip of the ablation catheter relative to specific anatomical structures. Another option is visualization of the arrhythmogenic substrate in patients with ventricular arrhythmias. This article describes the clinical utility of ICE in non-fluoroscopic electrophysiology procedures more in detail.

Left ventricular fibro-fatty replacement in arrhythmogenic right ventricular dysplasia/cardiomyopathy: prevalence, patterns, and association with arrhythmias.

BACKGROUND: Left ventricular (LV) fibrofatty infiltration in arrhythmogenic right ventricular (RV) dysplasia/cardiomyopathy (ARVD/C) has been reported, however, detailed cardiovascular magnetic resonance (CMR) characteristics and association with outcomes are uncertain. We aim to describe LV findings on CMR in ARVD/C patients and their relationship with arrhythmic outcomes. METHODS: CMR of 73 subjects with ARVD/C according to the 2010 Task Force Criteria (TFC) were analyzed for LV involvement, defined as ≥ 1 of the following features: LV wall motion abnormality, LV late gadolinium enhancement (LGE), LV fat infiltration, or LV ejection fraction (LVEF) < 50%. Ventricular volumes and function, regional wall motion abnormalities, and the presence of ventricular fat or fibrosis were recorded. Findings on CMR were correlated with arrhythmic outcomes. RESULTS: Of the 73 subjects, 50.7% had CMR evidence for LV involvement. Proband status and advanced RV dysfunction were independently associated with LV abnormalities. The most common pattern of LV involvement was focal fatty infiltration in the sub-epicardium of the apicolateral LV with a "bite-like" pattern. LGE in the LV was found in the same distribution and most often had a linear appearance. LV involvement was more common with non-PKP2 genetic mutation variants, regardless of proband status. Only RV structural disease on CMR (HR 3.47, 95% CI 1.13-10.70) and prior arrhythmia (HR 2.85, 95% CI 1.33-6.10) were independently associated with arrhythmic events. CONCLUSION: Among patients with 2010 TFC for ARVD/C, CMR evidence for LV abnormalities are seen in half of patients and typically manifest as fibrofatty infiltration in the subepicardium of the apicolateral wall and are not associated with arrhythmic outcomes.

Acoustic radiation force impulse under clinical conditions with single infusion of ultrasound contrast agent evoking arrhythmias in rabbit heart.

PURPOSE: We previously reported that acoustic radiation force impulse (ARFI) with concomitant administration of perfluorobutane as an ultrasound contrast agent (UCA)-induced arrhythmias at a mechanical index (MI) of 1.8 or 4.0 in a rabbit model. The present study identified the location of arrhythmias with a MI < 1.8 using a new system that can transmit ARFI with B-mode imaging. METHODS: Under general anesthesia, six male Japanese white rabbits were placed in a supine position. Using this system, we targeted ARFI to the exact site of the heart. ARFI exposure with MI 0.9-1.2 was performed to the right or left ventricle of the heart 2 min after UCA injection. RESULTS: ARFI with a MI lower than previously reported to rabbit heart evoked extrasystolic waves with single UCA infusion. Arrhythmias were not observed using ARFI without UCA. Extrasystolic waves were observed significantly more frequently in the right ventricle group than in the left ventricle group, with arrhythmias showing reversed shapes. No fatal arrhythmias were observed. CONCLUSION: ARFI applied to simulate clinical conditions in rabbit heart evoked extrasystolic waves with single UCA infusion. The right ventricle group was significantly more sensitive to ARFI exposure, resulting in arrhythmias, than the left ventricle group. The shapes of PVCs that occurred in the right ventricle group and the left ventricle group were reversed. Ultrasound practitioners who use ARFI should be aware of this adverse reaction, even if the MI is below the previously determined value of 1.9.