Spiked Helmet Electrocardiographic Sign in a Patient with a Diagnosis of Thoracoabdominal Aortic Dissection

Abstract

We report the case of a patient who developed the spiked helmet electrocardiographic (ECG) sign concomitantly with a thoracoabdominal aortic dissection resulting in ischemic functional ileum with gastric distention. Prompt identification of this ECG sign could prevent unnecessary emergent percutaneous cardiac catheterization procedures. (Level of Difficulty: Beginner.)

Graphical abstract

Presentation

A 60-year-old male patient was at first transferred from the emergency department to the tertiary center for suspected aortic dissection. The day of the hospitalization, the patient manifested a sudden retrosternal pain at rest, radiating to the jugular region, followed by a transitory loss of consciousness without any prodromal symptoms.

Learning Objectives

• •To develop a differential diagnosis; a history of recent serious abdominal, thoracic or cranial pathology associated with this particular ECG regimen should immediately raise suspicion of a “pointed helmet sign.”
• •Timely identification of SHS and other commonly misunderstood electrocardiographic signs may prevent unnecessary percutaneous cardiac catheterization procedures.
• •To understand the role of extracardiac causes in the development of the spiked helmet sign, identification of SHS should immediately prompt an active search for an acute noncardiac disease.

On admission to the emergency department, the patient was hemodynamically stable with negative shock index but required low-flow oxygen. Very weak bilateral femoral artery pulse was palpable. The remainder of the physical examination was unremarkable.

The Aortic Dissection Detection Risk Score was 2 points with positive d-dimer blood test. These results mandated proceeding to computed tomography angiography (CTA) in that case according the triple-rule-out protocol.

CTA showed type A aortic dissection according to the Stanford classification. The dissection extended from the ascending aorta to both the external iliac arteries with left main coronary artery involvement. However, neither sign nor persistent symptoms of acute coronary syndrome could be appreciated.

The patient underwent urgent aortic surgery and a Bentall procedure with ascending aorta replacement associated with hemiarch replacement, using circulation arrest and extracorporeal circulation. No major complications occurred, and the patient was transferred to the authors’ cardiovascular intensive care unit. Early postoperative course took place in a regular manner. On the third postoperative day, the patient became hemodynamically unstable and showed clinical and laboratory markers of hypoperfusion.

Medical History

The patient’s medical history was notable only for hypertension and mild dilation of ascending aorta at regular follow-up.

Differential Diagnosis

The first differential diagnostic hypotheses focused on the possibility of an ongoing cardiac tamponade or on the possibility of an acute coronary syndrome due to possible thrombosis or detachment of the coronary arteries recently replanted at the level of the aortic prosthesis (Figure 1).

Figure 1.

Commonly Misunderstood Electrocardiographic Signs With Drawn-Out Analogies

ECG = electrocardiogram.

Investigations

We immediately performed a 12-lead ECG that showed repolarization abnormalities in the inferior leads that were strong suspects of an acute lower ST-segment elevation acute coronary syndrome. However, a more careful analysis of the ECG showed that the findings were consistent with a spiked helmet sign (SHS) (Figure 2).

Figure 2.

Electrocardiogram Showing the Transitory Spiked Helmet Sign in the Inferior Leads

Spiked helmet sign in inferior lead (red arrowheads). (A) The historical German military spiked helmet called the “Pickelhaube.” (B) The thickened black line (red arrowheads) resembles the electrocardiogram abnormalities shown in A. (C) Electrocardiogram demonstrates complete resolution of the spiked helmet sign after the nasogastric aspiration of abundant gastric content.

Medical and management interventions

An urgent coronary angiography was performed, and a potential source of myocardial ischemia was excluded from the normal result of this examination. As a subsequent investigation, the patient underwent a CTA of the thoracoabdominal aorta. The examination showed initial signs of intestinal ischemia due to intrinsic compression by the false aortic lumen on the celiac trunk and malperfusion of the inferior mesenteric artery emerging from the false lumen (Figure 3).

Figure 3.

Computed Tomography Angiography Shows Malperfusion of the Splanchnic Arteries Resulting from Abdominal Aorta Dissection

(A) Stenosis of the ostial and proximal celiac trunk (red arrow). (B) Malperfusion of the inferior mesenteric artery emerging from the aortic false lumen (red arrowhead).

The patient rapidly developed signs of ileum with abdominal distention and vomiting with a considerable amount of fluid suctioned by nasogastric tube. Notably, the ECG recording demonstrated complete resolution of the repolarization abnormalities after nasogastric aspiration of abundant content in the stomach. The patient underwent an urgent thoracoabdominal endovascular aorta repair, using an abdominal stent graft in the descending thoracic aorta as well as percutaneous arterial angioplasty and stenting of both the celiac trunk and the superior mesenteric artery. Endovascular repair was successful with satisfactory angiographic result.

Discussion

This report describes the peculiar case of a patient who developed the electrocardiographic SHS concomitantly with a thoracoabdominal dissection, both causing celiac trunk and inferior mesenteric artery stenosis. This condition resulted in ischemic functional ileum with significant gastric distention. In this case, recognition of the SHS could predict the concomitant misdiagnosed critical noncardiac condition.

In 2011, a new ECG phenomenon, the SHS, was first described in medical literature (1). This electrocardiographic abnormality was characterized by a dome and spike-patterned apparent ST-segment elevation, where the upward shift of the baseline started before the onset of the QRS complex. The morphology of this particular ECG pattern resembled the shape of the historical German military spiked helmet called “Pickelhaube,” used by the Prussian and German imperial armies from the mid-19th century to the First World War.

Evidence of this particular ECG abnormality is scarce. The importance of the SHS pattern relies on its association with critical noncardiac disease associated with a high risk of in-hospital mortality. The exact mechanisms underlying the SHS remains uncertain. SHS has been reported in patients with serious pathology conditions characterized by an increase in intra-abdominal or intrathoracic pressure as well as in patients with acute cerebrovascular events such as cerebral hemorrhage and subarachnoid hemorrhage (2). SHS has been reported in either the inferior leads or in the peripheral leads. Notably, different noncardiac acute conditions seemed to be associated with specific localizations of SHS in the 12-lead ECG.

SHS described in the inferior leads has usually been diagnosed in subjects with an acute abdominal event such as ileus, severe gastric distension, and bowel perforation (3). Similarly, SHS has been described in the peripheral leads diagnosed in subjects with acute thoracic conditions such as tension pneumothorax and thoracic aorta perforation (4). In those cases, the resolution of the underlying acute noncardiac condition invariably resulted in either prompt or progressive resolution of the SHS (4,5). More recently, SHS has been reported in conditions associated with marked QT interval prolongation such as Takotsubo syndrome and in conditions characterized by excessive sympathetic discharge such as intracranial and subarachnoid hemorrhage. The exact pathophysiological mechanism of the SHS has not been clarified so far. However, the manifestation of SHS, a cyclic upward shift of the baseline that precedes and follows the QRS complexes, probably has been attributed to the pulsatile epidermal stretch related to either the acute thoracic or abdominal distension, respectively. Consistently, human cardiac tissue contains stretch-activated ion channels which change conductivity under different stretch conditions. Similarly, human fibroblasts within the cutaneous layers have stretch-activated cation channels that show significant activity adaptation when either these are stretched over a period of several seconds or the static component persists for longer periods.

Coronary artery angiography can rule out sources of acute cardiac ischemia. However, the spiked helmet electrocardiographic sign persisted in the inferior leads until the prompt resolution after removal of abundant gastric content.

Follow-Up

During subsequent follow-up examinations, no further abnormalities of the ventricular repolarization on the ECG were detected. The present patient was discharged from the cardiovascular intensive care unit after 23 days from the admission.

Conclusions

This case report further supports the hypothesis that the SHS is associated with acute extracardiac conditions, despite apparent ST-segment elevation possibly suggesting a cardiac ischemic cause. The common mechanism of SHS is probably due to excessive sympathetic discharge as shown by the fact that the SHS presents under conditions such as Takotsubo cardiomyopathy, acute intracerebral and subarachnoid hemorrhage, or after stellate ganglion ablation.

This case highlights the importance of prompt identification of the SHS as well as the localization of this ECG abnormality because this could prevent unnecessary emergent percutaneous cardiac catheterizations and should prompt the active search for a potential concomitant acute noncardiac disease characterized by elevated sympathetic discharge as well as unfavorable outcomes.

Author Disclosures

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