The spiked helmet sign is an electrocardiographic (ECG) abnormality characterized by a dome-and-spike pattern where upright QRS complexes are preceded by upslope and followed by downslope of the ECG baseline. Numerous studies have demonstrated that the spiked helmet sign is a marker of critical, usually noncardiac illness and a high risk of death. In this report we describe an ECG abnormality we termed volcanic mountain sign that appears to be a variant of the spiked helmet sign. In the volcanic mountain sign, a negative QRS complex mimicking the central vent of a volcano starts from the top of a mountain-shaped dome or from the bottom of a crater-like depression. The volcanic mountain sign too is seen in patients with acute, severe and occasionally lethal noncardiac illnesses. Resolution of the acute clinical condition is associated with prompt resolution of the volcanic mountain sign.

In the acute care setting, the two most common causes of giant upright T waves include hyperkalemia and the very early phase of acute myocardial infarction (MI). The former is characterized by narrow based and peaked T waves. The giant T waves of early MI, also called “hyperacute T waves,” are usually more broad-based. The general recommendation is to consider hyperacute T waves a form of occlusion MI, and to proceed with emergent cardiac catheterization and revascularization. In this report, we present the case of a young man with cocaine toxicity and status epilepticus where the initial electrocardiogram (ECG) demonstrated giant T waves. Both hyperkalemia and coronary occlusion were ruled out. Within a few hours, the ECG spontaneously normalized. Review of the literature revealed that although uncommon, acute cerebral events including seizures can cause transient giant T waves. When giant T waves are noted in association with a cerebral event, emergent cardiac catheterization may not be warranted.

A 57-year-old woman with long history of polysubstance abuse was staying in a half-way house where she suffered a witnessed cardiac arrest. Bystander cardiopulmonary resuscitation was immediately initiated. An automatic external defibrillator detected four consecutive episodes of ventricular fibrillation, each successfully terminated by a single shock. The prehospital electrocardiogram (ECG) obtained by medics is shown in Figure 1. Immediately after arrival to the emergency department, cardiac telemetry demonstrated the onset of ventricular tachycardia which quickly degenerated into ventricular fibrillation requiring one more defibrillation shock (Figure 2). Figure 2Telemetry recordings in the emergency department. Panel A: Continuous strip demonstrating the onset of ventricular tachycardia. Panel B: Ventricular fibrillation terminated by an external shock. View Large Image Figure Viewer Download Hi-res image

Per journal policy, no abstract is required for the section EP Rounds.

A 69-year-old woman had three syncopal events while flying on an airplane. She was found to be profoundly bradycardic. Two 12‑lead electrocardiograms (ECGs) showed ventricular rates in the thirties. In one, the QRS complexes were narrow. In the second ECG, there were wide negative deflections following the QRS complexes. Analysis of telemetry recordings revealed the underlying mechanism and helped establish appropriate programing of an implanted pacemaker.

This case report describes a patient in their 60s with gastrointestinal bleeding and shock with heart rate overcounting by software indicating severe hyperkalemia.

The purpose of computerized analysis of electrocardiograms (ECGs) is to provide rapid interpretation in places where ECG experts are not available, and to save physician time for all providers. For the most part, contemporary interpretation algorithms perform remarkably well and offer correct diagnoses of common ECG abnormalities. Diagnostic accuracy for myocardial ischemia and infarction is reasonably good but with these conditions, false positive and false negative readings can be disastrous. It is essential, therefore, that computerized statements be over-read by trained physicians. A three-part mini-series is intended to provide assistance to quickly recognize and correct common interpretation software mistakes. This first chapter presents interpretation errors that falsely indicate myocardial infarction.

Electrocardiogram interpretation software mistakes can lead to incorrect diagnoses and inappropriate treatments. Occasionally, the consequences of not recognizing such mistakes are disastrous. This final chapter on software mistakes describes three relatively common computer errors that should never be missed because not recognizing them can result in stroke, cardiac arrest, and even death. In each of the scenarios covered, we describe the clinical background, and provide simple recommendations on how such mistakes can be easily identified and corrected.

Electrocardiogram (ECG) interpretation software mistakes can lead to incorrect diagnoses and inappropriate treatments. Occasionally, however, repetitive and consistent computer errors may hide important clues for correct diagnoses that otherwise could have been missed. We present a collection of a few common and clinically important such peculiarities, and provide tools on how to prove or disprove the suspected diagnosis. In addition to the illustrations in print, an online supplement (OS) shows more examples of the discussed phenomena. In each ECG, the original computer interpretations were enlarged for legibility.

A previously healthy and active 28-year-old male was hospitalized for a 3-hour history of sharp substernal chest pain that radiated to his jaw. The patient was uncomfortable, diaphoretic, and tachycardic. His initial heart rate and blood pressure were 120 bpm and 145/64 mmHg, respectively. The cardiac apex appeared to be hyperdynamic and peripheral pulsations were prominent. Otherwise, a quick physical examination was noted to be negative. The electrocardiogram (ECG) showed up to 5 mm diffuse ST elevation, interpreted as acute ST elevation infarct (STEMI) (Figure 1). The patient underwent emergent cardiac catheterization that did not show any coronary abnormality. On further questioning, he admitted to a 3-month history of hot flashes, sweating, palpitation, tremor, and 20-pound weight loss. Cardiac troponins remained negative.