Clinical articles

This article is available as a ‘Standalone BJC Learning module’ CPD activity

Background

Cardiac amyloidosis (CA) is a disorder of protein misfolding with resultant accumulation within the myocardium ultimately leading to clinical heart failure. It is subcategorised, according to the type of misfolded protein, into primary light-chain amyloidosis (AL) and transthyretin amyloidosis (ATTR). AL-CA is the result of cardiac infiltration of misfolded light-chain proteins; whereas ATTR-CA is caused by cardiac deposition of the misfolded thyroid hormone transport protein, transthyretin. ATTR-CA can be further subcategorised into hereditary (hATTR) versus wild-type (wtATTR).^1,2 Although the exact prevalence of ATTR-CA is unknown, it has become increasingly accepted as a common cause of heart failure, particularly in the elderly. Despite this knowledge, ATTR-CA remains a widely underdiagnosed cause of heart failure, and there are frequently delays to achieving the accurate diagnosis. Prompt recognition and early diagnosis of ATTR-CA is critical to decreasing morbidity and mortality, particularly as disease-modifying therapies emerge in the treatment of ATTR-CA. We present a case of ATTR-CA that remained undiagnosed until later disease stages and we will subsequently review the diagnostic evaluation of patients with suspected ATTR-CA.

This article is available as a ‘Standalone BJC Learning module’ CPD activity

Transthyretin amyloidosis (ATTR) is a progressive, fatal disease in which deposition of amyloid derived from either mutant or wild-type transthyretin (wtATTR) causes progressive and severe organ dysfunction. The two key clinical phenotypes are transthyretin amyloid cardiomyopathy (ATTR-CM) or transthyretin amyloid polyneuropathy (ATTR-PN), which both carry significant morbidity and mortality. Hereditary ATTR amyloidosis frequently presents with a mixed phenotype (ATTR-mixed).

ATTR-CM is an infiltrative, restrictive cardiomyopathy characterised by congestive cardiac failure, often with preserved left ventricular ejection fraction, and significant risk of conduction disease.

Treatment focuses on supportive care, reduction and ideally elimination of transthyretin (TTR) from the plasma, stabilisation of the tetramic structure of TTR and dissolution of the existing ATTR amyloid matrix.

Liver transplantation, to remove variant TTR production remains a treatment option for a select cohort of patients with hereditary ATTR-PN, although it is likely to be replaced by novel RNA-targeting therapies aimed at reducing TTR production. TTR stabilisers, such as tafamidis and acoramidis, may offer disease-modifying therapy to the majority of elderly patients with wild-type ATTR-CM. The rapidly evolving landscape of treatment options for ATTR amyloidosis, particularly among older patients with wtATTR, validates improved efforts to diagnose ATTR-CM.

Introduction

Hyperkalaemia (HK) in heart failure and chronic kidney disease patients limits the use of renin–angiotension–aldosterone system (RAAS) inhibitors, and successful intervention may allow patients to remain on optimal RAAS therapy. The management of HK is an established practice, but the increasing popularity of novel potassium binders may represent an effective and better-tolerated alternative compared with conventional therapy, such as sodium polystyrene sulfonate.¹

This article reviews the efficacy, and safety profile of patiromer and sodium zirconium cyclosilicate (SZC), and summarises the National Institute for Health and Care Excellence (NICE) guidance for both agents.^2,3

A wide range of medications including antimalarial preparations (chloroquine, hydroxychloroquine), macrolide antibiotics (azithromycin) and the interleukin-6 inhibitor (tocilizumab) may be effective in treating patients with coronavirus disease 2019 (COVID-19). Such agents may be associated with cardiotoxicity, and the purpose of this brief review is to draw attention to potential areas of pharmacovigilance. These include prolongation of the QT-interval and the development of occult cardiomyopathy. Alternatively, some of the agents seem to have minimal impact on the cardiovascular system. The review highlights the need for an ongoing evaluation of such agents within carefully constructed clinical trials with embedded attention to cardiovascular safety.

The reason to be cautious when evaluating curative or symptomatic treatments is the fact that SARS-CoV-2 has affected large segments of the population, with disproportionate mortality rates within certain subgroups. Some of the enhanced mortality may reflect inherent cardiovascular disease risk factors related to acute COVID-19 infection.

It is hoped that the review will stimulate a greater awareness of potential cardiovascular side effects and encourage reporting of those in future trials.

Around 7.4 million people in the UK have heart and cardiovascular disease, coronary artery disease (CAD) being the most common type. The Driving and Vehicle Licensing Agency (DVLA) has guidance for medical professionals to aid assessment of cardiac patients with respect to driving. The guidance is different for personal, Public Carriage Office (PCO) and goods vehicles. It remains the doctors’ responsibility to advise patients of any driving restrictions, as certain cardiac conditions can limit patients’ ability to drive. This gains importance especially after certain procedures. A retrospective review of discharge summaries from electronic medical records was undertaken for a period of three months to review the number of patients getting appropriate advice. It was noted that frequently no written driving advice was recorded on discharge, neglecting an important element of patient safety. Steps were taken to counteract the lack of proper driving advice and documentation, which were effective on second review. Therefore, measures similar to ones outlined here should be put in place to ensure safe discharge and knowledge of the clinicians in accordance with the DVLA guidance.

This study aims to present the screening, prevalence and treatment of heart failure (HF) patients with iron deficiency in an Irish hospital and use an economic model to estimate the budget impact of treating eligible patients with intravenous ferric carboxymaltose (IV FCM).

Retrospective data were collected on 151 HF patients over a one-year period from all newly referred HF patients to a secondary care hospital. This included 36 patients with preserved ejection fraction (HFpEF) and 115 with reduced ejection fraction (HPrEF). An existing budget impact model was adapted to incorporate Irish unit cost and resource use data to estimate the annual budget impact of treating patients with IV FCM.

The total number of HFrEF patients who met criteria for iron replacement was 44 (38% of total HFrEF patients); of this, only nine (20%) were treated. The budget impact model estimates that treating all eligible patients with IV FCM in this single centre would save 40 bed-days and over €7,600/year.

To improve the quality of life and reduce hospitalisation, further identification and treatment of iron deficient patients should be implemented. Expanding the use of IV iron nationally would be cost and bed saving.

Takotsubo syndrome – also known as broken-heart syndrome, Takotsubo cardiomyopathy, and stress-induced cardiomyopathy – is a recently discovered acute cardiac disease first described in Japan in 1991. This review aims to update understanding on the epidemiology, pathophysiology, clinical presentation, diagnosis, and treatment of Takotsubo syndrome, highlighting aspects of interest to cardiologists and general practitioners.

We describe two cases of Takotsubo syndrome and discuss the issues relating to diagnosis and patient communication that they raise.

The incremental shuttle walk test (ISWT) is a valid, reliable submaximal exercise test used in the assessment of patients prior to cardiac rehabilitation (CR). Simultaneous electrocardiogram (ECG) measurements would provide important information on the safety of the test, and adequacy of subsequent cardiac risk stratification. Risk stratification is recommended to assess patients’ suitability for cardiac rehabilitation. For example, ST-segment depression >2 mm from baseline during testing would place a person in a high-risk category. However, such ECG measurements are rarely undertaken in clinical practice. The aim of the study was to investigate the incidence of ECG changes during an ISWT, and report on the possible impact of these findings on subsequent cardiac risk stratification.

A retrospective case note review was undertaken for the year 2017. Baseline clinical characteristics from eligible patients were gathered including those with ischaemic heart disease, heart failure, transplant and valve replacement, along with ECG measurements during the ISWT. The impact of ECG findings on cardiac risk stratification was calculated, based on risk stratification developed by the American Association of Cardiovascular and Pulmonary Rehabilitation. The safety of the ISWT was measured by the absence of major ECG changes.

Data were gathered for 295 patients. Minor ECG changes were identified during the ISWT in 189 patients (64.1%), with no major changes. The presence of silent myocardial ischaemia (ST-segment depression) had an impact on cardiac risk stratification in 27 patients. There was a statistically significant positive association between ST-segment depression with cardiac risk stratification (p<0.001).

In conclusion, the ISWT is safe in terms of ECG changes. The impact of ECG findings on cardiac risk stratification is significant and worthy of further consideration.

The coronavirus disease 2019 (COVID-19) pandemic has produced a dramatic shift in how we practise medicine, with changes in working patterns, clinical commitments and training. Cardiology trainees in the UK have experienced a significant loss in training opportunities due to the loss of specialist outpatient clinics and reduction in procedural work, with those on subspecialty fellowships perhaps losing out the most. Training days, courses and conferences have also been cancelled or postponed. Many trainees have been redeployed during the crisis, and routes of career progression have been greatly affected, prompting concerns about extensions in training time, along with effects on mental health.

With the pandemic ongoing and its effects on training likely long-lasting, we examine areas for improvement and opportunities for change in preparation for the ‘new normal’, including how other specialties have adapted. The increasingly routine use of video conferencing and online education has been a rare positive of the pandemic, and simulation will play a larger role. A more coordinated, national approach will need to be introduced to ensure curriculum components are covered and trainees around the country have equal access to ensure cardiology training in the UK remains world class.