Right ventricular strain assessment by cardiovascular magnetic resonance myocardial feature tracking allows optimized risk stratification in Takotsubo syndrome.

BACKGROUND: A substantial number of patients with Takotsubo syndrome (TTS) exhibit right ventricular (RV) dysfunction which has been associated with adverse outcome. The aim of this study was to assess the clinical and prognostic value of RV myocardial strain in TTS using cardiovascular magnetic resonance myocardial feature tracking (CMR-FT). METHODS: CMR-FT was performed in a core laboratory to determine RV longitudinal strain in 134 TTS patients undergoing CMR in median 2 days after admission to 2 experienced centers. For comparison, RV involvement was evaluated by sole visual assessment concerning RV contraction abnormalities. Both approaches were analyzed regarding their long-term prognostic value. RESULTS: The peak global RV longitudinal strain was in median -19%. Segmental analyses located contraction abnormalities primarily in the apical parts of the right ventricle. Sole visual assessment identified 38 patients (28%) with RV involvement. These patients showed a numerically higher long-term mortality without reaching statistical significance (17.1% versus 10.5%; hazard ratio 1.38 [95% confidence interval 0.49-3.88]; p = 0.31). The optimal RV strain cutoff value for risk prediction was -17.24%. Stratification according to this threshold categorized 41% of TTS patients (n = 55) in the high-risk group which demonstrated a significantly increased long-term mortality compared to patients with preserved global RV strain (20.0% versus 7.0%; hazard ratio 2.98 [95% confidence interval 1.02-8.73]; p = 0.03). CONCLUSIONS: The assessment of RV myocardial strain using CMR-FT enables an accurate evaluation of RV involvement in TTS and represents a promising approach for optimized risk stratification.

Functional and histological assessment of an experimental model of Takotsubo's cardiomyopathy.

BACKGROUND: Our objectives were to characterize functional and structural features of an experimental model of Takotsubo cardiomyopathy, and its response to beta-blockers. METHODS AND RESULTS: In protocol 1, a dose-finding study: 69 rats received various doses of isoproterenol (ISO) and echocardiographic and histologic parameters were measured on days 2 to 3 or day 8. There were no dose-dependent effects and, out of 69 ISO-treated rats, 40 (58.0%) survived and 29 (42.0%) died within 24 hours. Of survivors, 30 had apical akinesis averaging 12.1 ± 1.6% of the long axis LV circumference. Out of the 40 survivors, 32.5% showed apical akinesis ≥ 10%, 42.5% showed akinesis<10% and 25% showed no apical akinesis. The basal portion of the LV was always preserved. At 24 hours, histology and ultrastructure showed necrosis, vacuolization, lipid droplets, mononuclear cell infiltration, damaged mitochondria, and edema. On day 8, apical akinesis fully resolved but histologic abnormalities were still present. In protocol 2, rats were randomized to Control; ISO100 mg/kg; propranolol+ISO; and metoprolol+ISO groups. Pretreatment with propranolol and metoprolol improved survival to 90% and 100% respectively, compared with 60% in the ISO group, but did not reduce the incidence and extent of akinesis or the structural damage. CONCLUSION: TC can be mimicked in a rat model of ISO exposure that demonstrates apical akinesis on days 2 to 3 with full recovery of systolic regional wall motion abnormality despite the presence of persistent foci of necrosis and fibrosis on day 8. Pretreatment with beta-blockers improved survival but did not affect structural and functional alterations.

Assessment of left ventricular twist mechanics in Tako-tsubo cardiomyopathy by two-dimensional speckle-tracking echocardiography.

AIMS: To assess left ventricular (LV) twist mechanics in patients with Tako-tsubo cardiomyopathy (TTC). METHODS AND RESULTS: Two-dimensional strain and LV twist by speckle-tracking echocardiography was performed in 17 consecutive patients with typical TTC according to the Mayo clinic criteria [78 ± 8 years, 88% women, and mean left ventricular ejection fraction (LVEF) 45 ± 10%], at the acute phase (within 24 h after admission) and after recovery (1 month later). Seventeen control (C) patients matched for age and sex (mean LVEF 70 ± 7%), and 17 patients with acute anterior myocardial infarction (MI) treated by successful primary angioplasty 24 h before, matched for LVEF, age, and sex, were compared with TTC patients. LV twist was assessed using the parasternal basal and apical short-axis planes, and defined as the net difference in degrees of apical (Ar) and basal rotation (Br). Peak systolic and early diastolic, apical (As and Ad) and basal (Bs and Bd) rotation rate, and LV twisting rate (TR) and untwisting rate (UR) (in °/s) were derived from rotational and twist curves. The time sequences were normalized to the percentage of systolic duration. At the acute phase, Ar, As, Ad, Bs, LV twist (10 ± 9° vs. 23 ± 6°), LV TR, and LV UR were significantly impaired in patients with TTC when compared with controls (all, P < 0.05). Patients with MI displayed intermediate values (P = NS vs. TTC, and P < 0.05 vs. C). However, in the subgroup of patients with electrocardiogram ST-segment elevation at presentation (n = 12 TTC and 17 MI), several LV twist mechanics parameters were significantly reduced in TTC patients when compared with MI patients, LV twist, and LV TR being the most significant factors (all, P≤ 0.01). Abnormal reversed Ar (clockwise when seen from the apex) was seen in three patients (18%) with TTC vs. none in the other groups. A significant correlation between LV twist and LVEF, LV volumes, wall motion score index, and plasma NT-pro BNP was observed in the TTC group (all, P < 0.05). At follow-up, LV twist mechanics improved significantly in TTC patients (all, P < 0.05 vs. acute phase), who had final values similar to C (all, P = NS), whereas the magnitude of improvement was lower in MI patients (P ≤ 0.05 vs. TTC). CONCLUSION: LV twist mechanics is significantly impaired in patients with TTC mainly due to a severe reduction in apical function and is entirely reversible. Furthermore, in the subgroup of patients with ST-segment elevation, the early post-admission evaluation of LV twist mechanics is more severely impaired in TTC when compared with MI.

Echocardiographic assessment of regional left ventricular wall motion abnormalities in patients with tako-tsubo cardiomyopathy: comparison with anterior myocardial infarction.

AIMS: The aim of this study was to assess the echocardiographic distribution of regional wall motion abnormalities (RWMA) in patients with tako-tsubo cardiomyopathy (TTC) compared with anterior ST-elevation myocardial infarction (ant-STEMI). METHODS AND RESULTS: Thirty-seven TTC and 37 ant-STEMI patients underwent standard echocardiographic examination at the time of hospital admission. RWMA and the involvement of the left ventricular territories supplied by each coronary artery according to the American Society of Echocardiography classification were reported. TTC patients showed a lower left ventricular ejection fraction (37.6 ± 5.1 vs. 40.9 ± 3.7%; P = 0.002) and a higher wall motion score index (WMSI; 1.98 ± 0.2 vs. 1.51 ± 0.14; P < 0.001) compared with ant-STEMI patients. No significant differences were observed between groups with regard to detection of RWMA in the territory supplied by the left anterior descending coronary artery (LAD) (37 vs. 37; P = 1). Conversely, in TTC patients, the territories supplied by the LAD/left circumflex coronary artery (LCX) (37 vs. 31; P = 0.011), LAD/right coronary artery (RCA) (34 vs. 13; P < 0.001), RCA (33 vs. 5; P < 0.001), and RCA/LCX (31 vs. 2; P < 0.001) were more frequently involved. A cut-off value of WMSI ≥1.75 (area under the curve 0.956) and for the number of territories with RWMA ≥4 (AUC = 0.928) predicted TTC with a sensitivity of 83 and 84% and a specificity of 100 and 97%, respectively. CONCLUSION: Echocardiography revealed a distinctive pattern of contractility in TTC patients, characterized by symmetrical RWMA extending equally into the territory of distribution of all coronary arteries.

Takotsubo cardiomyopathy: assessment with cardiac MRI.

OBJECTIVE: The objective of this article is to show how MRI findings can be used to differentiate Takotsubo cardiomyopathy from acute coronary syndrome. CONCLUSION: Takotsubo cardiomyopathy is a disorder that mimics acute coronary syndrome. MRI can show not only edema in the ventricular wall, which is diffuse and without arterial territory distribution, but also motion abnormalities with typical akinesis in the apical and mid planes. Moreover, MRI can detect potential complications such as obstruction of the left ventricular outflow tract or thrombus in the left ventricular cavity.