The Spiked Helmet Sign

Abstract

We present the case of an 18-year-old man, with a history of subarachnoid hemorrhage, who is found to have the spiked helmet sign on electrocardiogram during a hospital admission for severe respiratory infection. The spiked helmet sign is a poorly understood electrocardiographic finding that mimics other electrocardiographic pathologies, and is associated with critical illness and high mortality. (Level of Difficulty: Beginner.)

Central Illustration

Case

An 18-year-old man with a history of motor vehicle accident complicated by subarachnoid hemorrhage and quadriplegia presented to the hospital with hypoxic respiratory failure and sepsis secondary to aspiration pneumonia. The patient spent 1 month in the intensive care unit and required mechanical ventilation. Following extubation, the patient had recurrent aspiration events as he was unable to clear oral and gastric secretions from his airway. His stay was further complicated by nosocomial coronavirus disease-2019 infection and new aspiration pneumonia. His telemetry monitoring showed changes with tachycardia and T-wave changes. The 12-lead electrocardiogram (ECG) that was obtained is shown in Figure 1.

Figure 1.

Electrocardiogram Obtained During Hospitalization

The following are shown: pseudo ST-segment elevations, which begin prior to the QRS complex, seen in nearly all leads and most notably in V₃-V₆. Pseudo ST-segment depressions with similar pattern are noted in aVR and V₁. Heart rate is regular at 126 beats/min.

What is the diagnosis?

This ECG pattern is mostly associated with:

• A.Electrolyte abnormality
• B.Coronary artery obstruction
• C.Increased intrathoracic or intra-abdominal pressure
• D.Pericardial effusion

The correct answer is C.

Explanation

The pattern shown in the ECG in Figure 1 is known as the “spiked helmet” sign. It is recognized by its dome-and-spike or sine-wave-like appearance, with QRS complexes forming spike-like protrusions. It gets its name from its resemblance to the Pickelhaube, the helmet worn by soldiers in late 19th century Prussia (1). The sign shows a pseudo ST-segment elevation, but the elevation is in fact associated with upsloping that begins prior to the QRS complex, which is inconsistent with ischemia. Although often described in the inferior leads, it has been observed in other leads as well. The QRS complex is notably well preserved but appears buried in the dome shape, and the P waves are usually not visible. The presence of the QRS complex helps separate it from other sine-wave-like patterns seen in hyperkalemia or torsade de pointes. The spiked helmet sign is a recently described ECG finding and is often associated with critical illness and a high risk of mortality. It has also been associated with increased intrathoracic or intra-abdominal pressures, sepsis, respiratory distress, subarachnoid hemorrhage, and anoxic brain injury (2). It is not a sign of cardiac pathology and is usually self-limited without any lasting ECG changes (1,2). Although the exact mechanism behind it is not fully understood, diaphragmatic breathing, synchronization of the cardiac pulse with pulsatile diaphragmatic contractions, and repetitive epidermal stretching have all been suggested as potential factors playing a role in the development of the sign (1,2). In this case, the patient was in a critical state, had a history of subarachnoid hemorrhage, and was being treated for severe lung infections, which are all features associated with the spiked helmet sign.

Ethical Considerations

The case and ECG were discussed after the patient had been discharged and we could not reach him to obtain consent. This paper presents the case with no identifier information and minimal clinical information on the patient’s disease and hospital course, ensuring that the patient’s privacy is protected.

Funding Support and Author Disclosures

The authors have reported that they have no relationships relevant to the contents of this paper to disclose.