Case Report


The American Heart Hospital Journal Figure 1: Rhythm Strip Showing Non-sustained Monomorphic Ventricular Tachycardia at 300 Beats per Minute


manifestations of thyrotoxicosis. Up to 6% of patients with thyrotoxicosis develop symptoms of heart failure, of which <1% develop dilated cardiomyopathy with systolic dysfunction via a tachycardia-mediated mechanism.3


Very few reports of paroxysmal VT are found in the literature. These include the case of a 90-year-old man with subclinical hyperthyroidism in the setting of a myocardial infarction,4


a case in a patient with heart failure5 and a case


of repetitive monomorphic ventricular tachycardia in a four-year-old boy with toxic multinodular goiter.6


with thyrotoxicosis in the absence of structural heart disease


1. Rotman-Pikielny P, Borodin O, Zissin R, et al., Newly diagnosed throtoxicosis in hospitalized patients: clinical characteristics, QJM, 2008;101(11):871–4.


2. Klein I, Ojamaa K, Thyroid hormone and the cardiovascular system, N Engl J Med, 2001;344:501–9.


3. Dahl P, Danzi S, Klein I, Thyrotoxic cardiac disease, Curr Heart Fail Rep, 2008;5(3):170–6.


4. Patane S, Marte F, Paroxysmal ventricular tachycardia and paroxysmal atrial fibrillation associated with subclinical hyperthyroidism, chronic renal failure and elevation of prostate-


Cardiac


arrhythmias due to thyrotoxicosis are perpetually supraventricular in origin.6


Monomorphic VT associated


is exceedingly rare. Generally, repetitive monomorphic VT produces no symptoms and has a good prognosis. The underlying mechanism, although not entirely clear, is often attributed to re-entry and triggered activity.6


case, the patient had received suboptimal treatment for hyperthyroidism and presented with repeated episodes of unsustained monomorphic VT as a result of thyrotoxicity.


Conclusion


It is important to recognize repetitive monomorphic VT as an understated but important manifestation of thyrotoxicosis. Propranolol is associated with an excellent response in these patients and anti-thyroid medications such as methimazole effectively reverse thyrotoxicity. n


specific antigen during acute myocardial infarcation, Int J Cardiol, 2010;138(3):e44–6.


5. Sato K, Omi Y, Kodama H, et al., Differential diagnosis and appropriate treatment of four thyrotoxicosis patients with Graves’ disease required to take amiodarone due to life-threatening arrhythmia, Intern Med, 2008;47(8):757–62.


6. Minegishi Y, Kumada S, Suzuki H, et al., Repetitive monomorphic ventricular tachycardia in a 4-year-old boy with toxic multinodular goiter, Acta Paediatr Scand, 1991;80:726–31.


In this


114


Repetitive Monomorphic Ventricular Tachycardia as a Manifestation of Suboptimally Treated Thyrotoxicosis


Winter 2010


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68