Role of Cardiac Magnetic Resonance (CMR) in Determining Implantable Cardioverter-Defibrillator (ICD) Indication in Acromegalic Cardiomyopathy: A Case Report

Potentially fatal arrhythmia is one of the causes of premature death in acromegalic cardiomyopathy patients who are not properly treated. Implantable cardioverter-defibrillator (ICD) is one of the most effective and established treatments to prevent sudden cardiac death due to potentially fatal tachyarrhythmia. However, since the indication of ICD changes depending on whether it is ischemic cardiomyopathy or non-ischemic cardiomyopathy, proper diagnosis is important in patients with these diseases. Cardiac magnetic resonance (CMR) is a convenient and useful tool for diagnosing these. Both potentially fatal arrhythmias and coronary artery disease (CAD) are known to be important complications of acromegaly. Herein, we present a case of potentially fatal tachyarrhythmia due to acromegalic cardiomyopathy with the acute coronary syndrome. Furthermore, we mention the usefulness of CMR in the case which is difficult to determine the indication for an ICD.

Specific FSTL1 polymorphism may determine the risk of cardiomyopathy in patients with acromegaly

BACKGROUND

We have investigated the role of a cardiomyokine, follistatin-like 1 (FSTL1), and its single nucleotide polymorphism on acromegalic cardiomyopathy.

METHODS

The study was performed as a cross-sectional case research in a Tertiary Referral Centre. Forty-six patients with acromegaly (29 F-17 M, mean age: 50.3 ± 12.1 years) were included. FSTL1 levels were measured and the rs1259293 region of the FSTL1 gene was subjected to polymorphism analysis. 1.5 Tesla MRI was used to obtain cardiac images.

RESULTS

There were 15 active (6 F-9M) and 31 (22 F-9M) controlled patients. Active patients had a higher left ventricular mass (LVM) and left ventricular mass index (LVMi). GH levels were positively correlated with left ventricular end-diastolic volume index (LVEDVi), stroke volume index (SVi), cardiac index (Ci), LVM and LVMi; r = 0.35, 0.38, 0.34, 0.39 and 0.39, respectively. IGF-1 index was positively correlated with LVEDVi, left ventricular end-systolic volume index (LVESVi), SVi, Ci, LVM and LVMi; r = 0.36, 0.34, 0.32, 0.31, 0.42 and 0.42, respectively. Twenty out of 46 patients with acromegaly (43.5%) had myocardial fibrosis. FSTL1 levels were neither correlated with disease activity nor with any functional and structural cardiac parameter. Multivariate linear regression analysis revealed no association between FSTL1 and any study parameters. The rs1259293 variant genotype CC was significantly associated with low left ventricular mass.

CONCLUSIONS

Serum FSTL1 levels are not associated with functional and structural measures of myocardium in patients with acromegaly. However, the risk of left ventricular hypertrophy is reduced in CC genotyped individuals of FSTL1.

[Heart arrhythmias and conduction disorders in patients with acromegaly: the role of cardiac magnetic resonance imaging]

Cardiovascular complications including arrhythmias and cardiac conduction disorders are one of the main reasons of high mortality rate in acromegaly, while they have not been well explored.

AIM

To estimate arrhythmias frequency in acromegaly, identify risk factors leading to the development of arrhythmia and cardiac conduction disorder, to determine the role of cardiac MRI in detecting structural and functional changes.

MATERIALS AND METHODS

A single-center prospective cohort study, which included 461 patients (151 men and 310 women) with acromegaly, was conducted. All the patients underwent a standard medical examination, including hormonal blood test, electrocardiogram, echocardiography, electrocardiogram daily monitoring. 18 patients with arrhythmias (11 men and 7 women) had cardiac MRI with gadolinium-based contrast.

RESULTS

The results of our research show high frequency of arrhythmias and cardiac conduction disorders in patients with acromegaly 42%. Most frequent kinds of arrhythmias and cardiac conduction disorders were sinus bradycardia 19.1% of the cases and conduction disorders of bundle branch blocks 14.5%. Men were more likely to suffer from arrhythmias and cardiac conduction disorders than women (54.2% and 37.4%, respectively,p=0.0005). Not acromegaly activity but duration of the disease was a main risk factor of arrhythmias and cardiac conduction disorders. Patients with arrhythmias had a long anamnesis of acromegaly (10 and 7 years, respectively, p=0.04). Meanwhile, cardiac conduction disorders were commonly observed in the patients who were treated with somatostatin analogs comparing to the patients who didnt undergo this therapy (50% and 38.6% respectively,p=0.004). We showed that 61% of patients with acromegaly and cardiac conduction disorders who underwent magnetic resonance imaging (MRI) had the signs of myocardial fibrosis. The value of the ejection fraction of the left ventricle according to MRI was higher than with echocardiography (p=0.04).

CONCLUSION

Arrhythmias and cardiac conduction disorders are often observed in patients with acromegaly even with remission of the disease. High risk group need careful diagnostic and monitoring approaches. Cardiac MRI is the gold standard for visualization of structural and morphological changes in the heart. Use of cardiac MRI in acromegalic patients expands our understanding of arrhythmias and cardiac conduction disorders in this disease. There are no specific laboratory markers of diffuse myocardial fibrosis, and the role of myocardial fibrosis in the occurrence of cardiac arrhythmias and conduction disorders needs further studying.

Bringing Cardiovascular Comorbidities in Acromegaly to an Update. How Should We Diagnose and Manage Them?

Patients with acromegaly frequently develop cardiovascular comorbidities, which significantly affect their morbidity and contribute to an increased all-cause mortality. In this regard, the most frequent complications that these patients may encounter include hypertension, cardiomyopathy, heart valve disease, arrhythmias, atherosclerosis, and coronary artery disease. The specific underlying mechanisms involved in the pathophysiology of these comorbidities are not always fully understood, but uncontrolled GH/IGF-I excess, age, prolonged disease duration, and coexistence of other cardio-vascular risk factors have been identified as significant influencing predisposing factors. It is important that clinicians bear in mind the potential development of cardiovascular comorbidities in acromegalic patients, in order to promptly tackle them, and avoid the progression of cardiac abnormalities. In many cases, this approach may be performed using straightforward screening tools, which will guide us for further diagnosis and management of cardiovascular complications. This article focuses on those cardiovascular comorbidities that are most frequently encountered in acromegalic patients, describes their pathophysiology, and suggests some recommendations for an early and optimal diagnosis, management and treatment.

Cardiovascular comorbidities in acromegaly: an update on their diagnosis and management

Comorbidities related to the cardiovascular system are one of the most prevalent in patients with acromegaly, and contribute to an increased risk of morbidity and all-cause mortality. Specifically, hypertension, cardiomyopathy, heart valve disease, arrhythmias, atherosclerosis, coronary artery disease, and cardiac dysfunction may be frequent findings. Although the underlying physiopathology for each comorbidity may not be fully elucidated, uncontrolled growth hormone/insulin-like growth factor 1 excess, age, prolonged disease duration, and coexistence of other cardio-vascular risk factors are significant influencing variables. A simple diagnostic approach to screen for the presence of these comorbidities may allow prompt treatment and arrest the progression of cardiac abnormalities. In this article, we revise the most prevalent cardiovascular comorbidities and their pathophysiology in acromegalic patients, and we address some recommendations for their prompt diagnosis, management and treatment. Strengths and pitfalls of different diagnostic techniques that are currently being used and how different treatments can affect these complications will be further discussed.