Association of identifiable triggers with recovery of high-grade atrioventricular block in takotsubo syndrome: a systematic review of case reports
H Hussein, P Derias, H Kassem, W Ali, P Tran, M KuehlAbstract
Background
High-grade atrioventricular block (AV block) is an uncommon complication of Takotsubo syndrome (TTS). Due to its low incidence and lack of randomized trials, there remain significant gaps in the evidence regarding its underlying mechanisms, the probability of conduction recovery, and the optimal timing for permanent pacemaker implantation [1, 2].
Methods
A systematic review was conducted on published case reports on TTS associated with high-grade AV block, diagnosed simultaneously or within the same hospital admission. Cases with low-grade AV block, sole sinus node disease, or TTS induced by pacemaker implantation were excluded. Additionally, reports lacking definitive diagnostic confirmation via coronary angiography, left ventriculography, or cardiac magnetic resonance imaging were excluded.
Results
A total of 50 cases were included in the final analysis and stratified into two groups based on AV block recovery. Fifteen patients (30%) developed complete AV block recovery. Compared to patients with persistent AV block, those who experienced recovery were younger (median [IQR] 66 [61-73] vs 77 [65-82], p = 0.02), more frequently reported identifiable emotional or physical stressors (93% vs 49%, p = 0.004), and demonstrated earlier recovery of left ventricular ejection fraction within one week (60% vs 24%, p = 0.02). No significant differences were observed between the groups in terms of comorbidities (hypertension in 27% vs 47%, p = 0.22), presenting symptoms (chest pain in 40% vs 14%, syncope or presyncope in 27% vs 46%, p = 0.22), ECG changes (ST elevation in 27% vs 14%, p = 0.28), or patterns of regional wall motion abnormalities (apical akinesia in 47% vs 46%, p = 0.93). On multivariate analysis, the presence of an identifiable stressor was the only independent predictor of AV block recovery (HR: 8.27; 95%CI: 1.07-63.73, p = 0.04).
Conclusion
In patients with TTS complicated by high-grade AV block, the absence of an identifiable trigger may indicate pre-existing conduction system disease and a higher likelihood of persistent AV block despite recovery of left ventricular ejection fraction (LVEF). Younger age and early LVEF recovery (within 1 week) appeared to be associated with AV conduction recovery and may help inform decisions regarding permanent pacemaker implantation. Further research is still required to clarify the pathophysiology of AV block and the optimal timing for pacemaker implantation in TTS.For image description, please refer to the figure legend and surrounding text.For image description, please refer to the figure legend and surrounding text.