Shark Fin Electrocardiogram: A Deadly Electrocardiogram Pattern in ST-Elevation Myocardial Infarction (STEMI)

Shark Fin Electrocardiogram: A Deadly Electrocardiogram Pattern in Takotsubo Cardiomyopathy During 15 Years of Follow-Up

Takotsubo cardiomyopathy (TTC) or stress-induced cardiomyopathy is characterized by transient left ventricular apical ballooning in the absence of coronary occlusion. Although the underlying mechanism is still unknown, exaggerated sympathetic nervous system and catecholamine cardiotoxicity, followed by metabolic disturbance, and multi-vessel epicardial coronary artery vasospasm, are thought to be responsible for the development of this condition. TTC accounts for 1-2% of patients presenting with the acute coronary syndrome (ACS) with the majority of patients being postmenopausal women. Shark fin electrocardiogram (SFE) or triangular ST-segment elevation is an uncommon electrocardiogram (ECG) finding that is typically associated with an increased risk of ventricular fibrillation and cardiogenic shock, thus, it is considered a poor prognostic factor. We present a case of a 57-year-old postmenopausal female with TTC post-colonic perforation. Upon further investigation, an ECG revealed an SFE or triangular ST-segment elevation on the anterolateral leads, and an elevated serum troponin level was found. On trans-thoracic echocardiogram (TTE), hypokinesis and akinesis of the apex and left ventricular segments were observed with sparing of the basal segments. Eventually, the patient was successfully managed and monitored until regain of normal function.

Shark Sighting in an Electrocardiogram

This case report describes a patient in their late 50s with elevated high-sensitivity cardiac troponin and a medical history of poorly controlled diabetes and cocaine, cannabis, and tobacco use.

SHARK FIN ECG PATTERN IN A PATIENT WITH TAKOTSUBO SYNDROME - CASE STUDY AND LITERATURE REVIEW

Shark fin or triangular QRS-ST-T waveform ECG pattern, also known as lambda-wave ST elevation or giant R wave syndrome, is a particular ECG presentation where QRS complex, ST-segment and T-wave are fused in a unique complex. Originally described in some patients with ST-segment elevation myocardial infarction (STEMI) during the acute phase, it has been found to be associated with a high risk of ventricular fibrillation and cardiogenic shock as well as with a high in-hospital mortality. However, shark fin ECG pattern has also been reported in patients with non-acute coronary syndrome related ST-elevation (NASTEP), including stress-induced takotsubo syndrome (TTS). Fourteen such cases (all females) have been reported so far. The authors present a case of a 56-year-old male with shark fin ECG pattern associated with TTS triggered by burn injuries of head, back, upper, lower limbs and the respiratory tract. Due to respiratory insufficiency and heart failure with hemodynamic compromise, he required mechanical ventilation and catecholamines use. Echocardiography showed apical and midventricular akinesia with left ventricular ejection fraction and global longitudinal strain reduced to 30% and -6.8%, respectively and a high segmental post-systolic index. Shark fin pattern maintained within 2 days, then ST-T evolution was observed. Echocardiographic improvement followed by almost normalization were seen after 6 and 9 days, respectively. No cardiac arrhythmias were recorded as in most of the described cases with shark fin ECG and TTS.

High-risk Electrocardiogram Patterns

This case report describes a patient in their 50s who presented to the emergency department with the presence of typical retrosternal chest pain radiating to the left scapular site.

A single-center retrospective study on the incidence and clinical significance of the electrocardiographic "Triangular QRS-ST-T Waveform" pattern*

BACKGROUND

The triangular QRS-ST-T waveform is a rare presentation of ST-segment elevation acute myocardial infarction associated with a poor in-hospital prognosis.

OBJECTIVE

To evaluate the incidence and clinical implications of the QRS-ST-T waveform pattern.

METHODS

Clinical data from non-pregnant adult patients who presented as STEMI activations at a single institution between 2017 and 2021 were reviewed. Patients who met electrocardiographic criteria for triangular QRS-ST-T waveform - a giant wave from the fusion of the QRS complex, the ST-segment, and the T-wave - were included in the study.

RESULTS

There were 417 STEMI activations, eight (1.9%) of which fulfilled the criteria for the triangular QRS-ST-T waveform pattern on electrocardiography. Coronary angiography was performed in five of these patients, four of whom demonstrated a significant lesion to the left anterior descending artery. Three patients did not undergo angiography secondary to hemodynamic instability. Seven of the patients in our study experienced cardiogenic shock requiring vasopressor, inotropic, and/or mechanical support. Only two patients survived to discharge; one was successfully bridged to coronary artery bypass grafting via intra-aortic balloon pump, while the other underwent a staged percutaneous coronary intervention.

CONCLUSIONS

The triangular QRS-ST-T waveform pattern is a rare ECG finding that may indicate hyper-acute STEMI and is an ominous sign of impending hemodynamic instability. Patients who survived received prompt aggressive therapeutic management.