Left ventricular global longitudinal strain assessment in patients with takotsubo cardiomyopathy: a call for an echocardiography-based classification.

Background: Takotsubo cardiomyopathy (TTC) is classified into 4 types depending on the anatomical area affected identified on gross visual assessment. We have sought to understand if it is feasible and advantageous to use left ventricular global longitudinal strain (LVGLS), LV segmental longitudinal strain and right ventricle free wall strain (RVFWS) to classify TTC.

Methods: We conducted a retrospective observational study on twenty-five patients who meet the Modified Mayo Clinic Criteria for TTC [1]. Two independent reviewers performed strain analysis, they were both blinded to patient's diagnosed classification and outcomes.

Results: Based on classification by traditional assessment the 92% (N.=23) were diagnosed with typical TTC, indicating apical involvement. The entire LV was affected, 67% (N.=16) had abnormal strain (STE>-18) in all three LV regions (base, mid-ventricle and apex). Seventy-one percent of patients (N.=17) had abnormal LVGLS (>-18). Abnormal strain across all three LV regions was associated with higher prevalence (70%, N.=8 Vs 30%, N.=4, respectively) of composite cardiovascular events and longer length of hospital stay. There was a statistically significant difference in average length of hospital stay in those patients who had abnormal strain in all three regions compared to those that did not have abnormal strain across all three regions (8 days compared to 3.44 days, P=0.02).

Conclusions: A new classification of TCC based on strain analysis should be developed. The traditional model is arbitrary; it fails to recognize that in most patients the entire LV is affect, it does not have prognostic significance and the most prevalent typical variant indicates apical involvement. Our study suggests that the entire LV is affected, and strain analysis has prognostic significance.