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This case report describes a patient in their 60s with a history of several months of recurrent dizziness and occasional palpitation who presented to the emergency department after an episode of syncope.

According to conventional teaching, the limb leads in the electrocardiogram (ECG) represent the frontal plane electrical vectors of the heart, whereas the chest leads signify the horizontal plane. The anterior chest leads V1-V2-V3, however, also have strong frontal plane representation which can result in morphological similarities in these leads to the augmented unipolar leads of the Einthoven triangle. This review highlights the significance of recognizing V1-V2-V3 as not only horizontal, but also as frontal plane leads. Appreciation of this phenomenon helps elucidate a colorful variety of clinically important but seemingly bizarre ECG manifestations that could not be explained otherwise.

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

Electrocardiographic (ECG) artifact, a common nuisance, has a wide range of manifestations with varying clinical significance. Beyond loose leads, motion artifacts and broken wires, artifact can also be caused by external and implanted devices as well as by physiologic signals. ECG artifact can mimic a variety of serious clinical conditions and arrhythmias such as acute myocardial infarction and ventricular tachycardia. The purpose of this review is to provide a structured approach to the recognition of the different forms of ECG artifact and to offer simple and practical steps to avoid misdiagnoses caused by artifact. Special attention is given to artifact whose presence can actually aid in the diagnosis of important and sometimes critical clinical conditions.

The modified Sgarbossa criteria have been established to aid in the diagnosis of ST-elevation myocardial infarction in patients with left bundle branch block. Thus far, the sensitivities and specificities of the Sgarbossa signs have only been evaluated retrospectively in cohorts of patients with and without occlusive myocardial infarctions. These statistical analyses were based on correlating ST abnormalities with serum markers of myocardial injury and/or results of emergent cardiac catheterization. We present a patient with acute cardiovascular emergency where electrocardiograms revealed intermittent left bundle branch block. In serial ECGs, highly dynamic ST abnormalities on the narrow QRS beats were associated with similarly dynamic ST changes in the left bundle branch block beats. Our findings provided direct and real-time confirmation of the usefulness of the Sgarbossa and the modified Sgarbossa criteria in the diagnosis of acute ST elevation in patients with left bundle branch block.

The vast majority of patients with acute occlusion of the proximal left anterior descending coronary artery (LAD) suffer frank ST-elevation myocardial infarction (STEMI). In contrast, a small but not insignificant minority presents with an electrocardiographic (ECG) pattern termed the "de Winter sign." The de Winter sign is characterized by upsloping ST depression followed by tall and peaked T waves in the precordial leads. The purpose of this report is to present two cases of acute obstruction of a large wrap-around LAD where the ECGs simultaneously displayed diagnostic criteria both for STEMI and the de Winter sign. We provide possible explanations for this hitherto undescribed phenomenon.

Cocaine is one of the most widely used illicit drugs in the U.S. [1]. We present a case of fatal cardiac arrest following cocaine abuse. The patient’s electrocardiograms demonstrated malignant dysr...

One of the more common causes of bigeminy at the ventricular level is type 1 second-degree atrioventricular (AV) block with 3:2 conduction ratio. In 3:2 Wenckebach, the shorter cycles reflect the consecutively conducted impulses and the longer cycles coincide with the blocked P waves. Theoretically, however, depending on the degree of conduction delay between the first and second transmitted impulses, other types of spacing of the QRS complexes may become possible. In this retrospective study of 180 patients who underwent electrophysiologic studies for symptomatic arrhythmias, atrial pacing-induced 3:2 Wenckebach periodicity resulted in a regular ventricular rate and/or in “reverse bigeminy” in 16 cases (8.9%). Reverse bigeminy was characterized by the shorter R-R intervals including both the blocked P waves and the first conducted beats of the subsequent cycles, and the longer R-R intervals coinciding with the second conducted beats during 3:2 Wenckebach. In 14 cases, regular ventricular rate and reverse bigeminy was triggered by marked conduction delay in the AV node and in 2 cases, the conduction delay was in the His-Purkinje system. Reverse bigeminy appeared to be related to dual AV nodal physiology in 8 patients. In 2 cases, sophisticated maneuvers such as termination of atrial pacing at critical intervals during the AV Wenckebach were required to expose the true conduction pattern. This study demonstrates that during rapid atrial rhythms, one cannot always be sure which P wave is responsible for which QRS complex. Rarely, extreme conduction delays can result in P waves conducting across the subsequent ventricular beats and be responsible not for the first, but for the following QRS complexes.

A man in his 70s was taking a medication that required routine electrocardiographic (ECG) monitoring for possible QT prolongation. On one of these occasions, four consecutive ECGs were recorded within 1 min. Unexpectedly, the rate-corrected QT intervals (QTc) reported by the interpretation software showed marked fluctuation ranging from 426 ms to 498 ms. Was there a rational explanation for the widely different QTc measurements? Was it necessary to hold the culprit medication?

A patient in their sixties with history of hypertension but no other cardiac history presented with 2 hours of severe substernal chest pain, diaphoresis, and lightheadedness. The patient’s heart rate was 68 beats per minute and their blood pressure was 112/78 mm Hg. Cardiac examination revealed distant heart sounds but no murmur or gallop. The Figure, A demonstrates the 12-lead electrocardiogram (ECG) taken on admission. In addition to probable left ventricular hypertrophy, it showed first-degree atrioventricular (AV) block and ST-segment elevation both in the inferior and in the anterior leads. The patient underwent emergency cardiac catheterization, which revealed single-vessel disease with acute thrombotic occlusion. Identify all potential conflicts of interest that might be relevant to your comment. Conflicts of interest comprise financial interests, activities, and relationships within the past 3 years including but not limited to employment, affiliation, grants or funding, consultancies, honoraria or payment, speaker's bureaus, stock ownership or options, expert testimony, royalties, donation of medical equipment, or patents planned, pending, or issued. Err on the side of full disclosure. If you have no conflicts of interest, check "No potential conflicts of interest" in the box below. The information will be posted with your response. Not all submitted comments are published. Please see our commenting policy for details.

A 66-year-old man with a medical history of hypertension and hyperlipidemia presented to an urgent care center with sudden-onset severe midsternal chest tightness and associated palpitation, diaphoresis, and shortness of breath. The patient had similar episodes in the past that resolved spontaneously. The ECG showed wide-complex tachycardia with a rate in the low 200s as shown in Figure 1A. Given the patient’s stable blood pressure, he was started on procainamide therapy with an initial 100 mg intravenous bolus followed by an infusion. Within minutes, the patient converted to sinus rhythm with resolution of his symptoms. Repeat ECG, however, was now concerning for lateral ST-segment–elevation myocardial infarction (Figure 1B). Note the 2- to 5-mm upward convex ST elevation followed by negative T waves in leads V4, V5, and V6. Aspirin, heparin, and atorvastatin were initiated, and the patient was transferred to a higher level of care for emergent cardiac catheterization. There the troponin level was negative, and cardiac catheterization did not show any …

A middle-aged man had repeat hospitalizations and interventions over several years for ventricular tachyarrhythmias and then, a 2-year history of progressive heart failure. Twelve-lead electrocardiogram recorded 10 months apart established the most likely cause and prognosis of the heart failure, and predicted its definitive treatment.

The evaluation and treatment of wide QRS-complex tachycardia remains a challenge, and mismanagement is quite common. Diagnostic aids such as wide-complex tachycardia algorithms perform poorly in the real-life setting. The purpose of this review is to offer a simple clinical-electrocardiographic approach for the initial evaluation and management of the adult patient with stable wide-complex tachycardia that does not require recollection of complex guidelines or algorithms.

Subarachnoid hemorrhage (SAH) is occasionally associated with the electrocardiographic (ECG) pattern of ST-segment elevation myocardial infarction (STEMI). Missing the true clinical diagnosis can result in inappropriate and harmful interventions. We report the case of a 40-year-old female who was found down. The ECG was diagnostic for acute lateral STEMI. Further analysis of the ECG showed marked prolongation of the QT interval and the "spiked helmet sign" (SHS). The patient was ruled out for myocardial infarction and a head CT demonstrated a massive SAH with acute hemorrhage into the ventricles. Review of the literature and of our own ECG files revealed additional cases where severe acute central nervous system (CNS) conditions were associated with the SHS.

Severe hyperkalemia is a hazardous condition that warrants urgent intervention. In critically ill patients, the electrocardiogram (ECG) can be the most immediately available diagnostic tool in identifying patients with potentially lethal hyperkalemia. Peaking of the T waves, the most widely appreciated ECG sign, is actually rarely a manifestation of life-threatening hyperkalemia. In this review, we provide several clinical-electrocardiographic manifestations that can help identify those patients with hyperkalemia who require prompt intervention.

Objectives: Heart failure (HF) is associated with high mortality and frequent hospitalizations. Disease management programs (DMPs) have a favorable impact on patients with HF. No data exist regarding the outcomes of patients discharged from such a program. Methods: We examined the outcome of patients with severe systolic HF who were discharged from a DMP following full clinical and echocardiographic recovery. Data were reviewed for mortality, emergency room visits, hospitalizations, medication adherence and left ventricular ejection fraction (EF). Results: At enrollment and discharge, the mean EF was 19 and 53%, respectively. At follow-up 46.2 months after discharge, 56% of patients had been to the emergency room, 34% were hospitalized a total of 41 times and 20% had died. In the patients who required hospitalization for HF, the mean EF upon rehospitalization had dropped to 23.4%. Conclusions: Many patients with initially severe systolic HF who had an almost full recovery in a multidisciplinary DMP had very poor outcomes once they were discharged from the program. It may be appropriate to revisit the practice of discharging patients from DMPs once they have reached a specific clinical target.