Repolarization Injury and Occurrence of Torsades de Pointes During Acute Takotsubo Syndrome.

ABSTRACT

Background: During takotsubo syndrome (TS), QTc prolongation is common, reflecting repolarization injury and providing the substrate for torsades de pointes (TdP). TdP has been reported sporadically in TS, yet QTc prolongation and TdP risk are often overlooked during management. Objectives: In TS patients, we sought to document TdP incidence, characteristics of patients with TdP, and association of QTc with postdischarge survival. Methods: Among consecutive TS patients at a single institution, we documented admission and discharge QTc, TdP incidence, and postdischarge 1-year mortality from 2006 to 2019. For perspective regarding TdP-TS risk, we characterized all published TdP cases from 2003 to 2022. Results: Of 259 patients, median age was 68 (range 59-77) years; 92% were female. The QTc interval was prolonged (≥460 ms) on admission in 129 (49.8%) patients and at discharge in 140 (54%) patients. QTc was ≥500 ms either on admission or at discharge in 98 (37.8%) patients. In-hospital TdP incidence was 0.8%. Postdischarge mortality was associated with admission but not discharge, QTc <460 ms (1.6%); 460-499 ms (12.6%); ≥500 ms (8.8%); P = 0.0056. Among 38 published TdP-TS cases, 80% of TdP events were within 48 hours of hospitalization, 90% of events occurred with QTc ≥500 ms, and 47.5% of events occurred with QTc ≥600 ms. Conditions associated with TdP risk were present in fewer than one-third of patients. Conclusions: During TS, QTc ≥500 ms was frequent. TdP incidence was low, with unpredictable occurrence and observed almost entirely with QTc ≥500 ms. A normal admission QTc was associated with >98% survival at 1-year postdischarge.