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Corresponding author at: Department of Cardiology Center, Section of Cardiovascular Medicine, Japan Community Healthcare Organization Tokyo Yamate Medical Center, 3-22-1 Hyakunin-cho, Shinjuku-ku, Tokyo 169-0073, Japan. Tel.: +81 3 3364 0251; fax: +81 3 3364 5663
An association of atrial arrhythmias with takotsubo cardiomyopathy (TTC) has not been described previously. Here we report a 65-year-old male patient with TTC. The sudden appearance of atrioventricular block and subsequent bradycardia are believed to be key contributing factors for the development of TTC. Both ventricular tachyarrhythmia and various atrial arrhythmias, such as atrial flutter and atrial fibrillation, were observed during the initial management of the patient's TTC. We speculate that both the left ventricular contractile dysfunction and the arrhythmogenic activities may share a common underlying etiology in advanced heart failure patients with TTC.
<Learning objective: We describe a case of TTC complicated by ventricular tachycardia, atrial tachyarrhythmias, and an atrioventricular conduction disturbance and discuss the etiology of arrhythmogenic activities in TTC.>
]. There are few case reports that describe the association between atrial arrhythmias and TCC. Here we report a case of heart failure with advanced TTC in which ventricular tachycardia (VT), complete His-ventricular (HV) block, and atrial flutter were associated with arrhythmogenic manifestations.
Case report
A 65-year-old male patient was transferred to our hospital because of the sudden appearance of dyspnea. He suffered from mild intellectual disability, but it did not interfere with routine daily life, and there was no emotional or physical stress. He was well before he experienced chest dyspnea. His symptoms worsened and his family physician recommended that he undergo further examination for acute heart failure. On admission, his chest radiograph showed both bilateral pulmonary congestion and cardiomegaly with a cardiothoracic ratio of 61%. Ambulatory monitor electrocardiogram showed torsades de pointes-type VT with a mean cycle length of 240 ms (Fig. 1). The patient's hemodynamics collapsed during VT, but VT was terminated by transient cardio-pulmonary resuscitation without electrical cardioversion. The electrocardiogram displayed a regular junctional rhythm with a heart rate of 45 beats/min, atrial flutter, and a prolongation of QT interval (QTc: 693 ms) with a giant negative T wave in the precordial leads (Fig. 2). The laboratory data disclosed an elevated serum level of N-terminal pro-B-type natriuretic peptide (969.4 pg/mL). The serum levels of myocardial enzymes were within the normal range. The serum level of troponin I was also within the normal range (0.164 ng/mL). The ultrasound echocardiogram showed extensive akinesis of the left ventricular wall. Mechanical ventilation and temporary pacing were initiated to maintain appropriate hemodynamics. An emergent cardiac catheterization study was performed to exclude acute coronary syndrome. Coronary arteriography was normal, but left ventriculography showed systolic apical ballooning (Fig. 3). Based on these findings, the patient was diagnosed with TTC. Intravenous furosemide and carperitide were administered at the coronary care unit, and his systemic condition gradually improved.
Fig. 1Documentation of torsades de pointes-type ventricular tachycardia in an ambulatory monitor recording.
Fig. 2Twelve-lead electrocardiogram on admission. Serrated negative P′ wave in leads II, III, and aVF with a junctional regular rhythm of 45 beats per minute is demonstrated. Note the giant negative T wave on long QT interval (QTc; 693 ms) in precordial leads.
Fig. 3End-diastolic (A) and end-systolic (B) phase of left ventriculogram performed on admission. End-systolic phase left ventriculogram (B) demonstrating the typical apical ballooning (dotted line) characteristic of takotsubo cardiomyopathy.
An electrophysiological study performed 8 days after admission consistently confirmed both complete HV block and uncommon atrial flutter (Fig. 4). Post-pacing interval was identical to that of the tachycardia cycle lengths measured at the coronary sinus orifice, septal isthmus, and low lateral right atrium. The EnSite NavX™ (St. Jude Medical, St. Paul, MN, USA) electroanatomical mapping system showed clockwise rotation around the tricuspid annuls during atrial tachycardia. An implantable cardioverter–defibrillator (ICD) was implanted for backup pacing and for secondary prevention of VT after ablation of the cavotricuspid isthmus. The clinical course was uneventful; both the left ventricular dysfunction and the QT prolongation had returned to their normal range 6 months after discharge (Fig. 5). However, the atrioventricular block persisted, and paroxysmal atrial fibrillation was observed (Fig. 6). Aside from being consequent to advanced age, the precise cause of the HV block could not be determined, because the patient's previous history, laboratory data, and ultrasound echocardiogram did not indicate the presence of cardiac sarcoidosis, myocarditis, or non-ischemic myocardial disease, although an endocardial biopsy was not obtained.
Fig. 4Electrophysiological recording during atrial tachyarrhythmia (A) and sinus rhythm (B). Twenty-polar electrode catheter with an interelectrode distance of 5 mm covers tricuspid annulus. A1–2 is positioned at the coronary sinus orifice and A19–20 is positioned at the low lateral right atrium, respectively. Note clockwise atrial activation sequence at tricuspid annuls on A, suggesting the presence of clockwise atrial flutter. Complete HV block is recorded consistently in B. HBE, His bundle electrogram; RV, right ventricular electrogram. Paper speed is 100 mm/s.
Fig. 5Recovery of giant negative T waves in precordial electrocardiogram during clinical course. (A) On admission, (B) 5 days after admission, (C) 3 months after discharge, (D) 6 months after discharge.
] reported two cases of TTC initiated by advanced atrioventricular block and subsequent bradycardia. In the current case, an HV block-based bradycardia emerged initially, and was then followed by the appearance of bradycardia-oriented TTC.
It is interesting to note that three types of critical arrhythmia coexisted in a single TTC patient. VT probably developed as a result of advanced QT prolongation, a common electrical anomaly in TTC, and cardiopulmonary resuscitation was required for VT termination. The TTC patient's atrial flutter is rare, but could occur sometimes. The rate of its association with TTC was 1.9% as Pant and colleagues [
] suggested in their recent review of TCC. Lastly, the patient exhibited a complete HV block leading to subsequent bradycardia. The mechanisms responsible for the generation and coexistence of these three arrhythmias are unknown. We speculated that the HV block-based bradycardia preceded the appearance of TTC; thus, the bradycardia itself was not necessarily a consequence of the TTC. It is well known that atrial fibrillation and/or atrial flutter are frequently observed during the initial management of congestive heart failure; however, they are unrelated to the presence of TTC [
]. These observations did not indicate HV block and atrial flutter as specific electrical manifestations of TTC. Nevertheless, even if the HV block and subsequent bradycardia pre-existed before the appearance of TCC, we cannot completely exclude the possibility that the appearance of TCC itself may modify the generation and/or progression of not only the ventricular tachyarrhythmias, but of the atrial tachyarrhythmias as well. This is supported by recent clinical and experimental reports describing arrhythmogenic activities associated with stress-induced myocardium as a specific electrical manifestation [
It is generally accepted that contractile function is closely related to the proper function of the underlying Ca2+-handling proteins, such as sarcoplasmic Ca2+ ATPase (SERCA2a), ryanodine receptor (RyR2), phospholamban (PLN), and sarcolipin (SLN), in the normal and pathologic myocardium [
] reported that SERCA2a activity and its Ca2+ affinity were reduced by altered expression of the genes encoding SLN and PLN in TTC samples. They concluded that the contractile dysfunction seen in TTC is associated with specific alterations of Ca2+-handling proteins.
Several investigators have described the role of Ca2+-handling proteins not only in the development of contractile dysfunction, but also in the appearance of arrhythmogenic activities in stress-induced cardiac diseases [
] reported a large genomic deletion in the gene encoding RyR2 in catecholaminergic polymorphic VT, an arrhythmogenic disorder induced by adrenergic stress that leads to extended clinical phenotypes, such as AV node dysfunction, atrial fibrillation, and atrial standstill. Ju et al. [
] also reported on the expression of inositol 1,4,5-triphosphate receptors (IP3R2) as another class of Ca2+ release channels in addition to RyR2. They concluded that IP3R2 was expressed in the mouse sinoatrial node and related atrial tissues with similar distribution to RyR2 and SERCA2a, and possessed arrhythmogenic activities in the atria.
Therefore, based on the exposure of the myocardium to exogenous and endogenous stresses, an altered expression of Ca2+-handling proteins in the ventricular and atrial walls may alter existing and/or contribute to additional atrial arrhythmias seen in TTC, particularly when the hemodynamic deterioration is advanced, as in the current case. Unfortunately, our case does not offer a conclusive mechanistic insight between the generation of atrial arrhythmias and the progression of TCC. Further study of similar cases will be necessary.
Opinion varies as to whether an ICD should be implanted in TCC patients with complicating VT. A recent report suggests that patients with previous cardiac arrest, as in the present case, should be given an ICD [
]. These observations appear to offer evidence supporting the advantage of an ICD implantation in TCC patients as a secondary prevention, especially when a complete HV block coexists.
In conclusion, we reported an association of critical ventricular and atrial arrhythmias with an advanced case of TTC. We suggest that these arrhythmias may have a common etiology arising from an abnormal function of Ca2+-handling proteins and that the appearance of these arrhythmias may indicate disease severity and a remote prognosis.
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