Diagnostic yield of hypertrophic cardiomyopathy in first-degree relatives of decedents with idiopathic left ventricular hypertrophy.

AIMS: Idiopathic left ventricular hypertrophy (LVH) is defined as LVH in the absence of myocyte disarray or secondary causes. It is unclear whether idiopathic LVH represents the phenotypic spectrum of hypertrophic cardiomyopathy (HCM) or whether it is a unique disease entity. We aimed to ascertain the prevalence of HCM in first-degree relatives of decedents from sudden death with idiopathic LVH at autopsy. Decedents also underwent molecular autopsy to identify the presence of pathogenic variants in genes implicated in HCM. METHODS AND RESULTS: Families of 46 decedents with idiopathic LVH (125 first-degree relatives) were investigated with electrocardiogram, echocardiogram exercise tolerance test, cardiovascular magnetic resonance imaging, 24-h Holter, and ajmaline provocation test. Next-generation sequencing molecular autopsy was performed in 14 (30%) cases. Decedents with idiopathic LVH were aged 33 ± 14 years and 40 (87%) were male. Fourteen families (30%) comprising 16 individuals were diagnosed with cardiac disease, including Brugada syndrome (n = 8), long QT syndrome (n = 3), cardiomyopathy (n = 2), and Wolff-Parkinson-White syndrome (n = 1). None of the family members were diagnosed with HCM. Molecular autopsy did not identify any pathogenic or likely pathogenic variants in genes encoding sarcomeric proteins. Two decedents had pathogenic variants associated with long QT syndrome, which were confirmed in relatives with the clinical phenotype. One decedent had a pathogenic variant associated with Danon disease in the absence of any histopathological findings of the condition or clinical phenotype in the family. CONCLUSION: Idiopathic LVH appears to be a distinct disease entity from HCM and is associated with fatal arrhythmias in individuals with primary arrhythmia syndromes. Family screening in relatives of decedents with idiopathic LVH should be comprehensive and encompass the broader spectrum of inherited cardiac conditions, including channelopathies.

Assessing the Eligibility Criteria in Phase III Randomized Controlled Trials of Drug Therapy in Heart Failure With Preserved Ejection Fraction: The Critical Play-Off Between a "Pure" Patient Phenotype and the Generalizability of Trial Findings.

AIMS: To investigate the effect of the different eligibility criteria used by phase III clinical studies in heart failure with preserved ejection fraction (HFpEF) on patient selection, phenotype, and survival. METHODS AND RESULTS: We applied the key eligibility criteria of 7 phase III HFpEF studies (Digitalis Investigation Group Ancillary, Candesartan in Patients With Chronic Heart Failure and Preserved Left-Ventricular Ejection Fraction, Perindopril in Elderly People With Chronic Heart Failure, Irbesartan in Heart Failure With Preserved Systolic Function, Japanese Diastolic Heart Failure, Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist, and Efficacy and Safety of LCZ696 Compared to Valsartan, on Morbidity and Mortality in Heart Failure Patients With Preserved Ejection Fraction [PARAGON-HF; ongoing]) to a typical and well-characterized HFpEF population (n = 557) seen in modern European cardiological practice. Follow-up was available for a minimum of 24 months in each patient. Increasing the number of study eligibility criteria identifies a progressively smaller group of patients from real-life practice suitable for recruitment into clinical trials; using the J-DHF criteria, 81% of our clinic patients would have been eligible, whereas the PARAGON-HF criteria significantly reduced this proportion to 32%. The patients identified from our clinical population had similar mortality rates using the different criteria, which were consistently higher than those reported in the actual clinic trials. CONCLUSIONS: Trial eligibility criteria have become stricter with time, which reduces the number of eligible patients, affecting both generalizability of any findings and feasibility of completing an adequately powered trial. We could not find evidence that the additional criteria used in more recent randomized trials in HFpEF have identified patients at higher risk of all-cause mortality.

Cardiomyopathy as presenting sign of glycogenin-1 deficiency-report of three cases and review of the literature.

We describe a new type of cardiomyopathy caused by a mutation in the glycogenin-1 gene (GYG1). Three unrelated male patients aged 34 to 52 years with cardiomyopathy and abnormal glycogen storage on endomyocardial biopsy were homozygous for the missense mutation p.Asp102His in GYG1. The mutated glycogenin-1 protein was expressed in cardiac tissue but had lost its ability to autoglucosylate as demonstrated by an in vitro assay and western blot analysis. It was therefore unable to form the primer for normal glycogen synthesis. Two of the patients showed similar patterns of heart dilatation, reduced ejection fraction and extensive late gadolinium enhancement on cardiac magnetic resonance imaging. These two patients were severely affected, necessitating cardiac transplantation. The cardiomyocyte storage material was characterized by large inclusions of periodic acid and Schiff positive material that was partly resistant to alpha-amylase treatment consistent with polyglucosan. The storage material had, unlike normal glycogen, a partly fibrillar structure by electron microscopy. None of the patients showed signs or symptoms of muscle weakness but a skeletal muscle biopsy in one case revealed muscle fibres with abnormal glycogen storage. Glycogenin-1 deficiency is known as a rare cause of skeletal muscle glycogen storage disease, usually without cardiomyopathy. We demonstrate that it may also be the cause of severe cardiomyopathy and cardiac failure without skeletal muscle weakness. GYG1 should be included in cardiomyopathy gene panels.

Calibration of myocardial T2 and T1 against iron concentration.

BACKGROUND: The assessment of myocardial iron using T2* cardiovascular magnetic resonance (CMR) has been validated and calibrated, and is in clinical use. However, there is very limited data assessing the relaxation parameters T1 and T2 for measurement of human myocardial iron. METHODS: Twelve hearts were examined from transfusion-dependent patients: 11 with end-stage heart failure, either following death (n=7) or cardiac transplantation (n=4), and 1 heart from a patient who died from a stroke with no cardiac iron loading. Ex-vivo R1 and R2 measurements (R1=1/T1 and R2=1/T2) at 1.5 Tesla were compared with myocardial iron concentration measured using inductively coupled plasma atomic emission spectroscopy. RESULTS: From a single myocardial slice in formalin which was repeatedly examined, a modest decrease in T2 was observed with time, from mean (± SD) 23.7 ± 0.93 ms at baseline (13 days after death and formalin fixation) to 18.5 ± 1.41 ms at day 566 (p<0.001). Raw T2 values were therefore adjusted to correct for this fall over time. Myocardial R2 was correlated with iron concentration [Fe] (R2 0.566, p<0.001), but the correlation was stronger between LnR2 and Ln[Fe] (R2 0.790, p<0.001). The relation was [Fe] = 5081•(T2)-2.22 between T2 (ms) and myocardial iron (mg/g dry weight). Analysis of T1 proved challenging with a dichotomous distribution of T1, with very short T1 (mean 72.3 ± 25.8 ms) that was independent of iron concentration in all hearts stored in formalin for greater than 12 months. In the remaining hearts stored for <10 weeks prior to scanning, LnR1 and iron concentration were correlated but with marked scatter (R2 0.517, p<0.001). A linear relationship was present between T1 and T2 in the hearts stored for a short period (R2 0.657, p<0.001). CONCLUSION: Myocardial T2 correlates well with myocardial iron concentration, which raises the possibility that T2 may provide additive information to T2* for patients with myocardial siderosis. However, ex-vivo T1 measurements are less reliable due to the severe chemical effects of formalin on T1 shortening, and therefore T1 calibration may only be practical from in-vivo human studies.

International prevalence of transthyretin amyloid cardiomyopathy in high-risk patients with heart failure and preserved or mildly reduced ejection fraction.

BACKGROUND: Transthyretin amyloid cardiomyopathy (ATTR-CM) is an underdiagnosed cause of heart failure (HF). METHODS: This epidemiology study assessed the international prevalence of ATTR-CM among patients aged ≥60 years with a history of HF, left ventricular ejection fraction (LVEF) >40%, an end-diastolic interventricular septum thickness (IVST) ≥12 mm, but without diagnosed amyloidosis, history of LVEF ≤40%, cardiomyopathy of known cause, severe valvular, or coronary heart disease. ATTR-CM was determined using cardiac scintigraphy alongside exclusionary testing for light chain amyloidosis. The study was terminated early due to slow recruitment, without safety concerns. RESULTS: Overall, 56/315 (18%; 95% CI: 13.7-22.5) patients with evaluable scintigraphy had ATTR-CM, with a numerically higher prevalence in: Europe (24%) vs. other regions (9% Asia; 5% North America); at specialist vs non-specialist centres (26% vs. 11%); in males vs. females (24% vs. 10%); and in older vs. younger patients (e.g. >40% among those ≥85 years). Other risk markers (p<.05) included a history of carpal tunnel syndrome, higher N-terminal pro B-type natriuretic peptide concentration, and higher end-diastolic IVST. CONCLUSIONS: ATTR-CM was diagnosed in 18% (95% CI: 13.7-22.5) of evaluable patients with HF, LVEF >40%, and risk markers for ATTR-CM, but no previous diagnosis of amyloidosis. Recruitment bias may have contributed to regional variability. NCT04424914.

Updates in heart failure.

This review provides a contemporary overview of HF management and highlights the key studies which have informed recent European HF guidelines.

On T2* magnetic resonance and cardiac iron.

BACKGROUND: Measurement of myocardial iron is key to the clinical management of patients at risk of siderotic cardiomyopathy. The cardiovascular magnetic resonance relaxation parameter R2* (assessed clinically via its reciprocal, T2*) measured in the ventricular septum is used to assess cardiac iron, but iron calibration and distribution data in humans are limited. METHODS AND RESULTS: Twelve human hearts were studied from transfusion-dependent patients after either death (heart failure, n=7; stroke, n=1) or transplantation for end-stage heart failure (n=4). After cardiovascular magnetic resonance R2* measurement, tissue iron concentration was measured in multiple samples of each heart with inductively coupled plasma atomic emission spectroscopy. Iron distribution throughout the heart showed no systematic variation between segments, but epicardial iron concentration was higher than in the endocardium. The mean ± SD global myocardial iron causing severe heart failure in 10 patients was 5.98 ± 2.42 mg/g dry weight (range, 3.19 to 9.50 mg/g), but in 1 outlier case of heart failure was 25.9 mg/g dry weight. Myocardial ln[R2*] was strongly linearly correlated with ln[Fe] (R²=0.910, P<0.001), leading to [Fe]=45.0×(T2*)⁻¹·²² for the clinical calibration equation with [Fe] in milligrams per gram dry weight and T2* in milliseconds. Midventricular septal iron concentration and R2* were both highly representative of mean global myocardial iron. CONCLUSIONS: These data detail the iron distribution throughout the heart in iron overload and provide calibration in humans for cardiovascular magnetic resonance R2* against myocardial iron concentration. The iron values are of considerable interest in terms of the level of cardiac iron associated with iron-related death and indicate that the heart is more sensitive to iron loading than the liver. The results also validate the current clinical practice of monitoring cardiac iron in vivo by cardiovascular magnetic resonance of the midseptum.

The electrocardiographic features associated with cardiac amyloidosis of variant transthyretin isoleucine 122 type in Afro-Caribbean patients.

BACKGROUND: About 4% of African Americans possess the isoleucine 122 (V122I) variant of transthyretin, associated with cardiac amyloidosis beyond ages of 55 to 60 years. Transthyretin amyloidosis associated with variant V122I (ATTR V122I) is likely to be an important cause of heart failure in Afro-Caribbean populations, but the high prevalence of left ventricular hypertrophy (LVH) and lack of awareness of this genetic disorder pose diagnostic hurdles. We report the electrocardiographic (ECG) features of ATTR V122I in the largest clinical series to date. METHODS: Patients with ATTR V122I were identified in collaboration with the UK National Amyloidosis Centre. The ECG at presentation was assessed for cardiac rhythm, axis, and voltage complex size. RESULTS: We include 64 patients with ATTR V122I, with a median age of 74 years (range, 57-88 years). Normal or increased ECG voltage was present in 44.3% of patients, and overall 25% met the criteria for LVH. A significant negative correlation between voltage complex size and duration of illness was seen (P < .05). First-degree heart block was evident in 56% of patients in sinus rhythm. During follow-up (n = 17; median, 28 months), 50% of patients with initial first-degree heart block required pacing. CONCLUSION: Electrocardiographic voltages meet the criteria for LVH in one quarter of patients with ATTR V122I cardiac amyloidosis. The widely held belief that cardiac amyloidosis is associated with low-voltage complexes is likely to contribute to underdiagnosis of ATTR V122I. First-degree heart block is common at diagnosis and identifies patients at high risk for subsequent pacing requirement.

Arrhythmogenic cardiomyopathy and differential diagnosis with physiological right ventricular remodelling in athletes using cardiovascular magnetic resonance.

To describe the overlap between structural abnormalities typical of arrhythmogenic right ventricular cardiomyopathy (ARVC) and physiological right ventricular adaptation to exercise and differentiate between pathologic and physiologic findings using CMR. We compared CMR studies of 43 patients (mean age 49 ± 17 years, 49% males, 32 genotyped) with a definitive diagnosis of ARVC with 97 (mean age 45 ± 16 years, 61% males) healthy athletes. CMR was abnormal in 37 (86%) patients with ARVC, but only 23 (53%) fulfilled a major or minor CMR criterion according to the TFC. 7/20 patients who did not fulfil any CMR TFC showed pathological finding (RV RWMA and fibrosis in the LV or LV RWMA). RV was affected in isolation in 17 (39%) patients and 18 (42%) patients showed biventricular involvement. Common RV abnormalities included RWMA (n = 34; 79%), RV dilatation (n = 18; 42%), RV systolic dysfunction (≤ 45%) (n = 17; 40%) and RV LGE (n = 13; 30%). The predominant LV abnormality was LGE (n = 20; 47%). 22/32 (69%) patients exhibited a pathogenic variant: PKP2 (n = 17, 53%), DSP (n = 4, 13%) and DSC2 (n = 1, 3%). Sixteen (16%) athletes exceeded TFC cut-off values for RV volumes. None of the athletes exceeded a RV/LV end-diastolic volume ratio > 1.2, nor fulfilled TFC for impaired RV ejection fraction. The majority (86%) of ARVC patients demonstrate CMR abnormalities suggestive of cardiomyopathy but only 53% fulfil at least one of the CMR TFC. LV involvement is found in 50% cases. In athletes, an RV/LV end-diastolic volume ratio > 1.2 and impaired RV function (RVEF ≤ 45%) are strong predictors of pathology.

International reproducibility of single breathhold T2* MR for cardiac and liver iron assessment among five thalassemia centers.

PURPOSE: To examine the reproducibility of the single breathhold T2* technique from different scanners, after installation of standard methodology in five international centers. MATERIALS AND METHODS: Up to 10 patients from each center were scanned twice locally for local interstudy reproducibility of heart and liver T2*, and then flown to a central MR facility to be rescanned on a reference scanner for intercenter reproducibility. Interobserver reproducibility for all scans was also assessed. RESULTS: Of the 49 patients scanned, the intercenter reproducibility for T2* was 5.9% for the heart and 5.8% for the liver. Local interstudy reproducibility for T2* was 7.4% for the heart and 4.6% for the liver. Interobserver reproducibility for T2* was 5.4% for the heart and 4.4% for the liver. CONCLUSION: These data indicate that T2* MR may be developed into a widespread test for tissue siderosis providing that well-defined and approved imaging and analysis techniques are used.

The Role of Cardiovascular Magnetic Resonance Imaging in Heart Failure.

Cardiovascular imaging is key for the assessment of patients with heart failure. Today, cardiovascular magnetic resonance imaging plays an established role in the assessment of patients with suspected and confirmed heart failure syndromes, in particular identifying aetiology. Its role in informing prognosis and guiding decisions around therapy are evolving. Key strengths include its accuracy; reproducibility; unrestricted field of view; lack of radiation; multiple abilities to characterise myocardial tissue, thrombus and scar; as well as unparalleled assessment of left and right ventricular volumes. T2* has an established role in the assessment and follow-up of iron overload cardiomyopathy and a role for T1 in specific therapies for cardiac amyloid and Anderson-Fabry disease is emerging.

Femoral implantation and pull through as an adjunct to traditional methods in cardiac resynchronization therapy.

BACKGROUND: We have described the use of femoral access followed by pull through of the lead to a pectoral position to circumvent difficulty in implanting a left ventricular (LV) lead by standard methods. OBJECTIVE: The purpose of this study was to establish the effect of femoral implantation and pull through on the overall rate of success in percutaneous implantation of LV leads. METHODS: We collected data prospectively in all attempts at LV lead implantation from the time that we envisioned the femoral pull-through approach. RESULTS: In the 6 years to September 30, 2014, our group attempted to implant a new LV lead in 736 patients, including 16 who previously had failed attempts by other groups. A standard superior approach was successful in 726 of 731 patients (99.3%) in whom it was attempted. In 5 patients (0.7%), we failed to deliver a lead from a superior approach; in 5 of 16 patients, with previous failed attemtps (31%), we judged that those attempts had been exhaustive. In all 10 cases, LV lead placement was achieved from a femoral approach, with the procedure time being 186 ± 65 minutes. In the first case attempted, the pull through failed; the lead was tunneled to the pectoral generator. In 1 case, the coronary sinus was found to be occluded at the ostium: a transseptal approach was used with the subsequent pull through. No complication occurred. At 22.3 ± 18.5 months after the implantation, all systems implanted by a femoral approach continued to function. CONCLUSION: Used as an adjunct to standard methods, the femoral access and pull through method allows percutaneous LV lead placement in virtually all cases.

Afro-Caribbean Heart Failure in the United Kingdom: Cause, Outcomes, and ATTR V122I Cardiac Amyloidosis.

BACKGROUND: It has been reported that subjects of African descent present with heart failure at a younger age and because of different causes than whites. We present contemporary data from UK Afro-Caribbean patients in London. METHODS AND RESULTS: All patients with heart failure presenting to St George's Hospital Heart Failure clinic between 2005 and 2012 were included (n=1392). Patients were predominantly white (71%) and male (67%), and median age at presentation was 73 years (range, 18-100 years). In 211 Afro-Caribbean patients, the most common cause of heart failure was nonischemic dilated cardiomyopathy in 27.5% (whites, 19.9%; P<0.001). Lower rates of ischemic cardiomyopathy were observed (13% versus 41%; P<0.001). The fourth most common cause of heart failure in Afro-Caribbeans was cardiac amyloidosis (11.4%). The prevalence may have been even higher as not all patients were tested for amyloidosis. Patients with ATTR V122I had the worst prognosis compared with other causes of Afro-Caribbean heart failure and white patients. To better understand this condition, we analyzed data from the largest international cohort of ATTR V122I patients, followed up at the UK National Amyloidosis Center (n=72). Patients presented with cardiac failure (median age, 75 [range, 59-90] years). Median survival was 2.6 years from diagnosis. CONCLUSIONS: In London, the cause of heart failure varies depending on ethnicity and affects age of presentation and outcomes. In Afro-Caribbean patients, ATTR V122I is an underappreciated cause of heart failure, and cardiomyopathy is often misattributed to hypertension. As promising TTR therapies are in development, increased awareness and proactive detection are needed.

CMR-based differentiation of AL and ATTR cardiac amyloidosis.

OBJECTIVES: This study was devised to describe the different cardiac magnetic resonance (CMR) appearances in light chain amyloid (AL) and transthyretin-related amyloidosis (ATTR). BACKGROUND: CMR is increasingly used to investigate patients with suspected amyloidosis. Global subendocardial late gadolinium enhancement (LGE) has been reported as typical of AL amyloidosis, whereas different patterns have been noted in ATTR amyloidosis. METHODS: We performed de novo analyses on original DICOM magnetic resonance imaging in 46 patients with cardiac AL amyloidosis and 51 patients with ATTR type who had been referred to a specialist amyloidosis center between 2007 and 2012 after CMR. Histological examination was performed in all cases, with immunohistochemistry, to confirm systemic amyloidosis. RESULTS: Patients' median age was 68 ± 10 years, and 74% were male. Left ventricular mass was markedly increased in ATTR amyloidosis (228 g [202 to 267 g]) compared with AL type (167 g [137 to 191 g]) (p < 0.001). LGE was detected in all but 1 cardiac amyloidosis patient (AL type) and was substantially more extensive in ATTR compared with AL amyloidosis. Ninety percent of ATTR patients demonstrated transmural LGE compared with 37% of AL patients (p < 0.001). Right ventricular LGE was apparent in all ATTR patients but in only 33 AL patients (72%) (p < 0.001). Despite these findings, survival was significantly better in cardiac ATTR amyloidosis compared with AL type. We derived an LGE scoring system (Query Amyloid Late Enhancement) that independently differentiated ATTR from AL amyloidosis and, when incorporated into a logistic regression model with age and wall thickness, detected ATTR type with 87% sensitivity and 96% specificity. CONCLUSIONS: Transmural patterns of LGE distinguished ATTR from AL cardiac amyloidosis with high accuracy in this real-world analysis of CMR. Precise diagnosis of cardiac amyloidosis is crucial given the role of chemotherapy in AL type and with novel therapies for ATTR type currently in development.

Cardiac transthyretin amyloidosis.

Cardiac amyloidosis of transthyretin fibril protein (ATTR) type is an infiltrative cardiomyopathy characterised by ventricular wall thickening and diastolic heart failure. Increased access to cardiovascular magnetic resonance imaging has led to a marked increase in referrals to our centre of Caucasian patients with wild-type ATTR (senile systemic) amyloidosis and Afro-Caribbean patients with the hereditary ATTR V122I type. Both subtypes present predominantly as isolated cardiomyopathy. The differential diagnosis includes cardiac amyloid light-chain (AL) amyloidosis, which has a poorer prognosis and can be amenable to chemotherapy. We review here the clinical features of cardiac ATTR amyloidosis and describe the diagnostic tests to determine ATTR type. Correct diagnosis is ever more crucial given that several novel therapies for ATTR amyloidosis are on the near horizon.

Assessment of iron overload with T2* magnetic resonance imaging.

T2* is a magnetic relaxation property of any tissue and is inversely related to intracellular iron stores. Measurement is simple, quick, and robust and has high reproducibility. The ability to measure ventricular function plus T2* in the heart and liver during the same scan has revolutionized the understanding of iron storage disease and the management of the iron-loaded patient. The early findings using T2* challenged conventional teachings, and both the technique and the findings were initially viewed with scepticism. However, after a decade of work in validating, calibrating, and expanding access to this method, it is now accepted as the method of choice for tissue iron assessment. In the UK, where T2* measurement was first used in the clinical care of patients with thalassemia major, a large and significant fall in mortality has been seen in this patient group.

The role of echocardiographic deformation imaging in hypertrophic myopathies.

Echocardiography has a leading role in the routine assessment and diagnosis of hypertrophic ventricles. However, the use of M-mode echocardiography and measurement of global left ventricular function may be misleading. Traditionally, systolic function was thought to be preserved in patients with hypertrophic myopathies until the late stages of the disease, and hypertrophic myopathies were thought to affect the myocardium more diffusely than ischemic heart disease. Ultrasound deformation imaging, either by Doppler myocardial imaging or speckle tracking, provides more-sensitive detection of regional myocardial motion and deformation than standard echocardiography. Basic and clinical studies that apply these techniques have revealed early, often subclinical impairment in systolic function. This information allows the detection and treatment of myocardial dysfunction at an early stage, which is of high clinical importance. Physiological hypertrophic remodeling seen in athletes differs from pathological myocardial hypertrophy, which can be caused by compensatory reactive hypertrophy owing to pressure overload in patients with aortic stenosis or hypertension, as well as amyloidosis, Fabry disease or Friedreich ataxia. Each of the etiologies associated with hypertrophy demonstrate distinct regional changes in myocardial deformation, which allows identification of the underlying processes, and will improve the assessment and follow-up of patients with hypertrophic myopathies.