ABSTRACT: Catecholamine-induced cardiomyopathy has been recognized for decades. We present the case of a 21-year-old female referred for an electrophysiologic (EP) study who underwent an infusion of isoproterenol and epinephrine in an attempt to unmask an ectopic atrial tachycardia. Prior to leaving the study suite, the patient started complaining of chest pain and shortness of breath. Bedside echocardiography revealed a severely depressed left ventricular ejection fraction (EF) of 25–30% with basal-mid left ventricular cavity hypokinesis, but normal apical wall motion. Her coronary angiography was normal. Repeat echocardiography 48 hours post EP study revealed a normally contracting LV with an ejection fraction of 55–60%. Our case illustrates an interesting clinical setting of acute catecholamine-induced cardiomyopathy. Takotsubo syndrome has been classically attributed to an intense emotional or physical stress resulting in excessive serum catecholamine levels causing apical hypokinesis and sparing of basal left ventricular function. This case is felt to represent an uncommon presentation of takotsubo cardiomyopathy occurring during an EP study triggered by iatrogenic catecholamine excess and manifesting with mid-ventricular wall hypokinesis. J INVASIVE CARDIOL 2008;20:E310–E313 Catecholamine-induced cardiomyopathy has been studied for decades, primarily via animal models using high-dose catecholamine infusions (epinephrine and norepinephrine) to induce global myocardial dysfunction.1–4 In 1991, Japanese physicians coined the term “tako-tsubo” cardiomyopathy (TCM), or apical left ventricular dysfunction syndrome, which was characterized by transient wall motion abnormalities that did not match an epicardial vascular distribution. Common manifestations included a rapid drop in left ventricular ejection fraction and ballooning of the left ventricular apex with preserved contractile function in the base of the heart. Due to the classic wall motion abnormalities, the end-systolic left ventriculogram resembled a “tako-tsubo”, or “Japanese octopus catcher”.5,6 The literature on TCM has expanded from case reports and case series to systematic reviews and, recently, a large prospective study.7 The most common variants of this condition manifest classically with apical hypokinesis and slightly less commonly with a pattern of midventricular dysfunction.7 On rare occasions, patients present with a pattern characterized by basal hypokinesis with a normal or hypercontractile apex.8,9 We present a case of a young, otherwise healthy female with a structurally normal heart who developed TCM during an electrophysiology (EP) study marked by basal hypokinesis. This is the first reported case occurring during an EP study, and supports catecholamine excess as the probable mechanism for TCM. Case Report. A 21-year-old female had experienced several episodes of exertional syncope and was referred for definitive evaluation at our hospital. Her multiple syncopal episodes had been evaluated at outside institutions and she was felt to have either atrial tachycardia or flutter based on outpatient diagnostic testing. Her evaluation also included an echocardiogram which revealed a structurally normal heart and preserved ejection fraction. At our institution, she was taken to the EP suite for further evaluation and possible treatment of her suspected arrhythmia. During the procedure, she underwent isoproterenol followed by epinephrine infusion in an attempt to unmask an underlying ectopic atrial arrhythmia. After several hours of electrophysiological maneuvers, the procedure was aborted due to an inability to induce the arrhythmia. Prior to leaving the study suite, the patient started complaining of substernal chest pain and shortness of breath. A 12-lead electrocardiogram (ECG) revealed sinus tachycardia with increased T-wave amplituse, but no ST-elevation (Figure 1). Bedside echocardiography revealed a severely depressed left ventricular ejection fraction (LVEF) of 25–30% with basal-mid LV cavity hypokinesis, but normal apical wall motion (Figure 2). A portable chest X-ray was consistent with pulmonary edema. ECG post EPstudy demonstrated a prolonged QT interval that was not present prior to the study. Given her acute clinical presentation, expedited coronary angiography was performed revealing normal coronary arteries. The left ventriculogram showed and ejection fraction of 30–35% with akinesis of the base, but hyperdynamic apical wall motion (Figure 3). The patient was admitted to the telemetry unit for observation. Cardiac enzymes were trended and revealed a mildly elevated CK-MB, but a normal troponin-T level. The patient responded well to gentle diuresis with complete resolution of symptoms within 24 hours. Repeat echocardiography 48 hours post-EP study revealed normal left ventricular wall motion and an EF of 55–60%. The patient’s QT prolongation was transient, resolving approximately 48 hours after the EP study and was attributed to after-effects from her catecholamine cardiomyopathy. It has not recurred on follow-up ECGs at the present time (over 1 year after her admission). Given the patient’s extensive workup prior to her referral to our institution for syncope (repeated cardiology consultation, event monitors), and the inability to provoke arrhythmia during our EP study and the lack of a family history, there was a low suspicion for long QT-syndrome, and this possibility was not evaluated further. Since her admission, the patient has undergone regular follow up with a cardiologist, and has had no further syncopal episodes. She also underwent an extensive neurologic evaluation to include inpatient EEG and appropriate imaging (CT and MRI of her brain), and no neurologic etiology for her complaints were found. Discussion. In 1991, case reports and case series of transient left ventricular systolic dysfunction with characteristic wall motion abnormalities and absence of corresponding epicardial coronary artery disease began to emerge. These were referred to as “takotsubo” cardiomyopathy,5 or apical-ballooning syndrome. The literature has since expanded to report on variants from the typical apical-ballooning pattern to include syndromes marked by midventricular dysfunction and basal hypokinesis. Patients usually present with chest pain (65–70%) and dyspnea (16–18%).5,6,10 Other common presenting symptoms include fatigue, malaise, palpitations, evidence of acute congestive heart failure (pulmonary edema, peripheral edema).6 Cardiogenic shock (4.2%) and ventricular fibrillation (1.5%) are rare.10 Systematic reviews suggest TCM frequencies of 1.2–2.2% in patient populations presenting with possible acute coronary syndrome.7,10 It is most commonly seen in post-menopausal females, with a predilection for Asians. The most common ECG abnormality is ST-elevation (70–90%),5–7,10 and others include ST-depression, QTc prolongation, T-wave inversion, non-specific T-wave abnormalities, and Q-waves.6,10 Cardiac biomarkers (CK-MB and troponin) are typically mildly elevated (approximately 75% and 85%, respectively).5,10 Viral antibody titers are not elevated, inflammatory markers are often normal, and plasma catecholamine levels are typically higher.6 The hallmark of TCM is transient left ventricular dysfunction with abnormal wall motion that does not match an epicardial coronary artery distribution. Angiography typically shows coronary arteries that are free of obstructive lesions. Left ventricular contractility is diminished acutely, but recovers significantly over the first 7 days with complete resolution weeks to months later.10 Wall motion abnormalities are typically apical and midventricular in location, with preservation of basal wall motion.6,10 In one study, 60% of TCM had a typical apical pattern, and 40% displayed a midventricular wall motion abnormality. Case reports of a variant of this condition with a hypocontractile base and normal apex (“chestnut variant”) have been rarely described.9,11 In a review by Abdulla et al,12 patients with apical sparing were typically younger, premenopausal, had a higher ejection fractions at presentation, and a higher recurrence rate (19% in patients with apical sparing, 0% in those with apical hypokinesis). Regardless of pattern, wall motion abnormalities typically completely resolve in the majority of patients.10 The list of known precipitants for takotsubo cardiomyopathy is lengthy. Emotional stress (so-called “broken-heart syndrome” in the popular media), physical illnesses (from underlying non-cardiac conditions), and iatrogenic catecholamine dosing, are the common categories. The mechanism of emotional stress is felt to be exaggerated sympathetic stimulation.13 Observed motional stressors includes quarreling, vigorous excitation,6 unexpected death of relative or close friend, confrontational arguments, and devastating business or gambling losses. Examples of physical stressors include minor surgical procedures, general anesthesia, noncardiac illnesses such as acute sepsis, and exhausting physical work.6 There has been an increasing interest in this phenomenon as a cause for hemodynamic deterioration in patients in the medical intensive care unit. One study of 92 intensive care patients reported a 28% prevalence of TCM in the setting of noncardiac illnesses.4 There also have been several case reports where TCM developed in the setting of iatrogenic epinephrine exposure, even routine subcutaneous administration for local anesthesia.15
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