Hyperthyroidism-associated coronary spasm: A case of non-ST segment elevation myocardial infarction with thyrotoxicosis

Unexpected Grave's-induced acute myocardial infarction in a young female, a literature review based on a case report

INTRODUCTION

Myocardial ischemia can occur due to several causes, which result in an imbalance between the supply and demand of oxygen to cardiac muscles. One potential reason for this condition is the overwork of the heart due to hyperstimulated thyroid function.

CASE PRESENTATION

The patient was a 36-year-old woman who presented with left-sided chest pain, dyspnea, palpitation, and tremor. The initial evaluation showed evidence of myocardial ischemia (positive high-sensitivity troponin) caused by a hyperactive thyroid gland. The treatment for myocardial infarction, along with anti-thyroid medications, improved the patient's condition and subsided the symptoms. The coronary angiography revealed no pathologic finding, and the hypokinetic left ventricle, observed in the first echocardiogram, was resolved. The patient was discharged with an excellent clinical condition, and after the 4-month taking of a calcium channel blocker and tapering carbimazole, the thyroid function became normal, and her symptoms resolved completely.

CONCLUSION

Patients without evident risk factors for ischemic heart disease, such as non-diabetic, nonsmoker, and young individuals who presented with acute coronary syndrome, should be evaluated for a potential background reason for the imbalance between the oxygen demand and supply of the myocardium. The presence of palpitation, weight loss, tremors, insomnia, and anxiousness, along with ischemic signs, should make the physician think about the probability of the hyperthyroid-induced cardiovascular disorder.

CLINICAL KEY POINT

The initial presentation of hyperthyroidism might be accompanied by severe cardiac symptoms. When the demographic features are not aligned with usual ischemic heart disease, other probable symptoms and signs should be investigated, and thyroid function should be checked. The control of thyroid hyperactivity would result in the resolution of both cardiac and non-cardiac symptoms.

Cardiac evaluation in amiodarone-induced thyroid dysfunction with suspected cardiac ischemia?: a case report and review of the literature

BACKGROUND

Amiodarone-induced thyroid dysfunction (AIT) is a side-effect associated with the use of Amiodarone for the treatment of refractory arrythmias. Resulting hyperthyroidism can precipitate cardiac complications, including cardiac ischemia and myocardial infarction, although this has only been described in a few case reports.

CASE PRESENTATION

We present here a clinical scenario involving a 66-year-old male Caucasian patient under Amiodarone for atrial fibrillation, who developed AIT. In the presence of dyspnea, multiple cardiovascular risk factors and ECG abnormalities, a transthoracic echocardiogram was performed, showing inferobasal hypokinesia. This led to further investigations through a cardiac PET-CT, where cardiac ischemia was suspected. Ultimately, the coronary angiography revealed no abnormalities. Nonetheless, these extensive cardiologic investigations led to a delay in initiating an emergency endovascular revascularization for acute-on-chronic left limb ischemia. Although initial treatment using Carbimazole was not successful after three weeks, the patient reached euthyroidism after completion of the treatment with Prednisone so that eventually thyroidectomy was not performed. Endovascular revascularization was finally performed after more than one month.

CONCLUSIONS

We discuss here cardiac abnormalities in patients with AIT, which may be due to relative ischemia secondary to increased metabolic demand during hyperthyroidism. Improvement of cardiac complications is expected through an optimal AIT therapy including medical therapy as the primary approach and, when necessary, thyroidectomy. Cardiac investigations in the context of AIT should be carefully considered and may not justify delaying other crucial interventions. If considered mandatory, diagnostic procedures such as coronary angiography should be preferred to functional testing.

Coronary Vasospasm-Induced Myocardial Infarction: An Uncommon Presentation of Unrecognized Hyperthyroidism

Hyperthyroidism can present with cardiac issues, such as tachycardia, atrial fibrillation, and high output congestive heart failure. Rare case reports of coronary vasospasm leading to myocardial infarction (MI) are published. Of these cases, many are known to be hyperthyroid prior to cardiac presentation. We report a female patient with unrecognized thyrotoxicosis who presents with acute MI secondary to coronary vasospasm.

Hyperthyroidism presenting as ST Elevation Myocardial Infarction with Normal Coronaries - A Case Report

A 31-year-old male, apparently well, presented with typical chest pain. His ECG showed ST-elevation from V1-V4 and echocardiogram revealed anteroseptal wall hypokinesia with ejection fraction of 45%. Normal coronary arteries were seen on coronary angiogram. A thyroid function test showed elevated free T4 levels with suppressed thyroid stimulating hormone (TSH). Treatment with thionamides and beta-blockers improved symptoms. Upon review 4 months later he was well. Repeat echocardiogram showed good ejection fraction with no hypokinetic area.

ECG changes in patients with primary hyperthyroidism

INTRODUCTION

Thyroid hormones plays key role in regulating cardiovascular system. Its imbalance leads to various electrophysiological changes in cardiovascular system. This study was done to determine the frequency of electrocardiographic (ECG) changes in patients with primary hyperthyroidism.

METHODS

It was a descriptive cross-sectional study conducted in the Department of Medicine, Medical Unit III, Ward-7, Jinnah Postgraduate Medical Centre, Karachi, from October 2013 to April 2014. A total of 103 patients newly diagnosed with primary hyperthyroidism were included in this study. Venous blood samples were collected for T3, T3, TSH analyzed by radioimmunoassay. ECG was performed. Outcome variables were the ECG changes i.e. sinus tachycardia and atrial fibrillation.

RESULTS

The average age of the patients was 30.09±5.57 years (95%CI: 29 to 31.18). Out of 103 cases, 19 (18.45%) were male and 84 (81.55%) were female. Sinus tachycardia was observed in 60.19% (62/103) patients whereas atrial fibrillation was found in 11.65 (12/103) of cases.

CONCLUSION

In this study frequency of electrocardiographic changes in term of sinus tachycardia was high. This report has emphasized the importance of thyrotoxicosis as a cause of cardiac morbidity and mortality in patients with thyrotoxicosis. These cardiac complications are readily reversible if timely optimal treatment is offered.

Thyrotoxicosis Mimicking ST Elevation Myocardial Infarction

Hyperthyroidism is well known to be associated with cardiac disease. Delay in making the diagnosis and occurrence of complications are common and are associated with a worse outcome.

A 54-year-old male, non-smoker, with no past medical history and no significant family history presented to our hospital with severe left sided chest pain, “crushing” in nature. Electrocardiogram showed ST-segment elevations in the inferior leads. Troponin I level was 0.32 ng/mL (normal range 0-0.05 ng/mL) on presentation. The patient underwent an emergent coronary angiography which showed no evidence of occlusive coronary artery disease. The patient’s symptoms and signs prompted a high suspicion of thyrotoxicosis which was subsequently confirmed by a low thyroid stimulating hormone and high free thyroxine levels. The patient was given Methimazole and atenolol and his symptoms resolved.

Awareness of coronary vasospasm due to thyrotoxicosis should be raised in patients presenting with typical angina pectoris with subsequent normal coronary angiographic results. History and physical examination may suggest underlying hyperthyroidism, but the absence of typical findings does not rule out the diagnosis.