INTRODUCTION

Takotsubo syndrome (TTS) is a transient acute cardiac disorder with a similar presentation to ST-segment elevation myocardial infarction (STEMI).^1,2 TTS usually affects postmenopausal women and is characterized by a new cardiac motion abnormality that commonly involves the apex of the left ventricle in the absence of significant obstructive coronary artery disease.³ This interesting syndrome was first described in Japan about 16 years ago. In Japanese, takotsubo is the name given to the fishing jar used to catch an octopus. This jar has a wide base with a narrow neck, similar in shape to that of the clinical entity seen on left ventriculography in TTS.⁴ Many other names have been used for this syndrome, including transient left ventricular apical ballooning syndrome, stress-induced cardiomyopathy and ampulla cardiomyopathy.^5–7

Awareness of this rare syndrome is increasing and cases of TTS have been diagnosed and reported in many areas of the world among different ethnic groups. Most of the case series and reports in the literature describe TTS in Asians and Caucasians, who are considered the most commonly affected ethnic groups.^8–11 However, to our knowledge TTS has been described in African-American (AA) patients in only one case series and few case reports.¹² To further investigate the nature of this syndrome and how it behaves in this ethnic group, we compared the clinical characteristics of TTS in AA patients with those in patients from other ethnicities.

METHODS

Criteria

All patients fulfilled the suggested Mayo Clinic criteria for diagnosis of TTS (Table 1).²

RESULTS

The demographics, clinical characteristics, ECG findings and echocardiographic results of the AA group are included in Table 2 and of the NAA group in Table 3. All patients were postmenopausal females.³ The mean age of the AA group was 64 ± 14 years, and the mean age in the NAA group was 69 ± 11 years. All patients had complained of chest pain at presentation and five had associated dyspnea (two AA and three NAA).

All study patients reported either emotional or physical stress within a few hours before admission. The stressors included exacerbation of chronic obstructive pulmonary disease, thumb fracture with severe pain, intensive physical therapy, a heated argument, the death of a close relative or friend and a son who was injured in a traffic accident.

ST-segment elevation was observed in three NAA (3 of 4, 75%), but in only one AA patient (1 of 4, 25%). All AA patients (4 of 4, 100%) and three NAA (3 of 4, 75%) developed diffuse deep T-wave inversions (Figure 1). Prolongation of the QT interval was noticed with equal frequency in AA and NAA patients (3 of 4, 75%).

All patients had elevated cardiac biomarker levels, including troponin I. The mean peak troponin I level was 5.2 ng/ml in the NAA patients and 2.0 ng/ml in the AA patients.

All patients had 2-D Echo done at admission, and all had a low ejection fraction (EF) with a global wall motion abnormality of the left ventricle. The mean EF in AA patients was 25 ± 7% and that in NAA patients was 26 ± 5%.

All patients had an invasive coronary angiogram, except one AA patient who underwent a computerized tomography angiogram of the coronaries (the patient refused cardiac catheterization). None of the patients had evidence of significant obstructive coronary artery disease, and all patients who underwent an invasive coronary angiogram were assessed by left ventriculography, which confirmed a global left ventricular wall motion abnormality with apical ballooning (Figure 2 A and B). Of the eight patients, three (all NAA) developed hypotension and required hemodynamic support (intra-aortic balloon pump or vasopressors).

All patients improved clinically and the repeated 2-D Echo showed improvement of left ventricular function in all patients. The 2-D Echo of patient one showed resolution of the apical ballooning with improvement in EF from 20% to 35% within two weeks. In patient two, EF improved from 35% to 65% within 10 days. Patient three had an EF of 20% on admission that improved to more than 45% on repeated echo after six weeks. Patient four had an EF of 25% on admission that improved to 45% within two days. The EF of patients five and six increased from 20% and 30% to 65% and 60%, respectively, in two weeks. The EF of patient seven improved within six weeks (from 30% to 55%) and that of patient eight increased from 25% to 65% in about five weeks. The study results for the AA and NAA patients are summarized in Table 4.

DISCUSSION

Because little has been reported to date about the nature and clinical characteristics of TTS in African-American patients, our study is helpful in understanding this syndrome. We described TTS in this understudied ethnic group and highlighted the major differences observed in the characteristics of this group compared with those of patients from other ethnicities.

The most commonly reported presenting symptoms of TTS are chest pain and dyspnea, in 83.4% and 20.4% of patients, respectively.^1,11 Our data were consistent with those findings, showing that chest pain followed by dyspnea are the most common presenting symptoms in both AA and NAA patients. This finding differs from that reported in a recent study by Patel et al.¹² in which none of the AA patients experienced chest pain but most reported dyspnea at presentation.

Acute, severe emotional or physical stress is believed to be the main precipitating factor of TTS, but the exact pathogenesis is not well understood. Our data support this, with all patients in both groups reporting either major physical or emotional stressor preceding the onset of the symptoms. High catecholamine levels and microvascular dysfunction are thought to be important in TTS.^8,9 These factors could explain part of the clinical and histological findings of this syndrome, including the contraction-band necrosis and mononuclear infiltrates that have been described in the endomyocardial biopsies of some patients with TTS.⁸

The clinical presentation of TTS classically is similar to STEMI: patients experience chest pain and have elevated troponin levels and ST-segment elevation.² A recent systematic review of the literature found that ST-segment elevation was the most common ECG abnormality, reported in about 82% of patients, followed by T-wave inversion at 64%.¹¹ Our study was consistent with these data in the NAA group but not in the AA group, in which T-wave inversions were the most common ECG abnormality; however, ST elevation was an infrequent finding. The AA patients in our study were more likely to present as Non STEMI (NSTEMI), whereas the NAA were more likely to have the classic STEMI presentation.

The T-wave inversions in our AA patients involved multiple leads and were the most common ECG abnormality in this group. The deep and wide shape of the T waves looked similar to that of the NAA group. From these observations, we think that the T-wave abnormality in AA patients may not differ from that described in Caucasians and Asians with TTS and that the T waves in this interesting syndrome will be shown to have a characteristic shape.

Our observations are consistent with the QT prolongation that has been reported in many studies.^11–13 We found that QT prolongation in the AA group is as common as it is in the NAA group and that none of the patients in either group developed ventricular tachyarrhythmia during hospitalization, which has been reported in several case reports as a possible complication of TTS.¹¹We think that serious tachyarrhythmias are not a common complication of TTS and that the prolonged QT interval associated with this syndrome generally has a benign course. However, larger follow-up studies are needed to form a solid conclusion about this issue and to report the incidence of this complication.

Several acute complications of TTS have been reported in the literature, including ventricular fibrillation, cardiogenic shock, pulmonary edema, and, rarely, left ventricular rupture.^11–16 In our study, three patients developed hypotension and cardiogenic shock, all of whom were NAA patients and all of whom required hemodynamic support by intra-aortic balloon pump or vasopressors. These findings differed from those suggested in several reports about TTS in Caucasians and Asians, where the authors considered TTS a benign disease. From these observations, we think that close monitoring of patients with TTS is crucial, and we suggest conducting larger studies to address the in-hospital course of the disease and the short-term morbidity and mortality rates associated with it.

On the other hand, our study showed that none of the AA patients developed cardiogenic shock, although the mean EF of this group is almost the same as that for the NAA group. Why the AA patients in our study tolerated TTS better than the NAA patients and why none of them had hypotension or cardiogenic shock is unclear. Genetic background may be important, but more studies of AA patients with TTS are required to answer these questions and to explain the major differences we found in our study.

LIMITATIONS

There were some limitations in this study with respect to sample size and the study design. The number of the patients was small and all patients were females. The study was retrospective, which lacks the follow up to determine the long-term morbidity and mortality associated with TTS, if any. In addition, solid conclusions are difficult to form in this study; however, reporting these findings and differences may help to understand the nature of this syndrome

CONCLUSION

AA women with TTS have similar presenting symptoms as NAA women, however they may not have the classic ST segment elevation at presentation and may be more likely to present as NSTEMI. TTS is not always a benign condition and hemodynamic instability is a possible complication. Our AA patient group tolerated TTS better than the NAA group, and fewer developed hypotension or needed hemodynamic support.

Footnotes

Supervising Section Editor: Shahram Lotfipour, MD, MPH
Submission history: Submitted February 23, 2010; Revision received September 28, 2010; Accepted October 25, 2010
Reprints available through open access at http://scholarship.org/uc/uciem_westjem.

Address for Correspondence: Fayez E. Shamoon, MD, FACC, Department of Cardiology, St. Michael’s Medical Center, 111 Central Ave., Newark, NJ 07102, USA
Email: shucvd@smmcnj.org and Email: ayqs@yahoo.com

Conflicts of Interest: By the WestJEM article submission agreement, all authors are required to disclose all affiliations, funding sources, and financial or management relationships that could be perceived as potential sources of bias. The authors disclosed none.

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