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PICTURES IN CLINICAL MEDICINE
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Ventricular Fibrillation Following Bidirectional Tachycardia due to Digitalis Toxicity Yoshiaki Kaneko, Tadashi Nakajima, Tadanobu Irie and Masahiko Kurabayashi Key words: digitalis, ventricular fibrillation (Intern Med 50: 2243, 2011) (DOI: 10.2169/internalmedicine.50.6092)
On hospital day 29, bidirectional tachycardia characterized by QRS complexes with an alternating shift in the morphology on ECG monitoring, spontaneously developed (Picture 1A and B), followed by ventricular fibrillation (VF) (Picture 1C), which was successfully defibrillated by DCshock (Picture 1D). The serum level of digoxin was 2.4 ng/ mL, which was just above the upper limit of the therapeutic range. Serum potassium and magnesium were 2.7 mEq/L and 2.3 mEq/L, respectively. There may be an increased risk of an event of VF with digitalis therapy accompanied by left ventricular dysfunction and hypopotassemia (1). Digitalis toxicity causes bidirectional tachycardia (2). This case clearly exhibited the arrhythmic cascade which leads to the development of VF due to digital toxicity. Picture 1. The authors state that they have no Conflict of Interest (COI).
A 79-year-old woman with a previous history of hypertension, congestive heart failure and persistent atrial fibrillation was admitted to our hospital with a diagnosis of retroperitoneal abscess. Transthoracic echocardiography revealed a left ventricular ejection fraction of 55%. She received an intravenous administration of digoxin (0.125 mg daily) for rate control of atrial fibrillation from hospital day 9 and hemodialysis for acute renal failure from hospital day 15.
References 1. Minardo JD, Heger JJ, Miles WM, et al. Clinical characteristics of patients with ventricular fibrillation during antiarrhythmic drug therapy. N Engl J Med 319: 257-262, 1988. 2. Rosenbaum MB, Elizari MV, Lazzari JO. The mechanism of bidirectional tachycardia. Am Heart J 78: 4-12, 1969.
Department of Medicine and Biological Science, Gunma University Graduate School of Medicine, Japan Received for publication July 1, 2011; Accepted for publication July 5, 2011 Correspondence to Dr. Yoshiaki Kaneko,
[email protected] Ⓒ 2011 The Japanese Society of Internal Medicine Journal Website: http://www.naika.or.jp/imindex.html
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