Discussion 
CVS is infamous for its malignant, quite relatively uncommon, arrhythmogenic complications3,6,7. Recognizing and preventing this potential lethality with medical treatment and device therapy are a major cornerstone in the management of CVS patients8. The American Heart Association/American College of Cardiology/Heart Rhythm Society guidelines in 2017 have specifically addressed the issue of ICD placement in CVS patients9. ICD received a class IIa recommendation when medical therapy has failed in preventing CVS-induced SCD, and a class IIb recommendation in addition to medical therapy after a first episode of CVS-induced SCD. However, ICD remains under-utilized in this setting3 .
Though uncommon, the presence of a “shark fin” pattern on ECG (Fig. 1), consisting of the blurring of the QRS and T-wave with significant ST-elevation, indicates a large burden of myocardial ischemia5. Known to be a high-risk pattern, this rare ECG finding predicts cardiogenic shock and mortality5. A recently published report showed that the “shark fin” pattern is associated with ventricular arrhythmias and cardiogenic shock in Takotsubo syndrome10. Miranda et al reported the case of a 53-year-old patient, where a transient “shark fin” pattern could have been caused by left main coronary spasm11.
Our case suggests that there may be an association between CVS-induced ventricular arrhythmias and certain ECG patterns such as the QRS-ST-T “shark fin” pattern. This specific pattern may predict cardiac sudden death during vasospasm. We hypothesize that this “shark fin” pattern, previously reported as a life-threatening pattern in myocardial infarction4, may also indicate a lethal arrhythmogenic propensity in CVS patients. Therefore, if such a pattern is documented during CVS, we recommend implementing aggressive treatment strategies with medical and device therapy. Specifically, an ICD should be recommended despite stenting the potential target lesion, and that because of the diffuse and recurrent nature of CVS over time, as demonstrated in our observation where severe spasm recurred seven years after the initial episode.