Dynamic ST-Segment Abnormality.

A 37-year-old man came to the emergency department because of several days of intermittent chest pain. An electrocardiogram (ECG) showed sinus rhythm, left atrial and left ventricular enlargement, and an early repolarization pattern. A second ECG recorded 10 minutes later was strikingly different, with ST-segment elevation and large upright T waves in the anterior precordial leads, interpreted as evidence of an ST-segment elevation myocardial infarction, and the cardiac catheterization team was activated. Closer inspection of the ECG, however, disclosed that the changes were because of intermittent ventricular pre-excitation of the Wolff-Parkinson-White type, and no electrocardiographic, echocardiographic, or serum markers of myocardial infarction were found.

Malignant Early Repolarization.

A 27-year-old man presents with successfully resuscitated ventricular fibrillation. Structural and electrical causes of ventricular fibrillation in the young are presented along with a diagnostic strategy. Electrocardiographic features of malignant early repolarization are discussed.

Atrial flutter: Clinical risk factors and adverse outcomes in the Framingham Heart Study.

BACKGROUND: Few epidemiologic cohort studies have evaluated atrial flutter (flutter) as an arrhythmia distinct from atrial fibrillation (AF). OBJECTIVE: The purpose of this study was to examine the clinical correlates of flutter and its associated outcomes to distinguish them from those associated with AF in the Framingham Heart Study. METHODS: We reviewed and adjudicated electrocardiograms (ECGs) previously classified as flutter or AF/flutter and another 100 ECGs randomly selected from AF cases. We examined the clinical correlates of flutter by matching up to 5 AF and 5 referents to each flutter case using a nested case referent design. We determined the 10-year outcomes associated with flutter with Cox models. RESULTS: During mean follow-up of 33.0 ± 12.2 years, 112 participants (mean age 72 ± 10 years, 30% women) developed flutter. In multivariable analyses, smoking (odds ratio [OR] 2.84, 95% confidence interval [CI] 1.54-5.23), increased PR interval (OR 1.28 per SD, 95% CI 1.03-1.60), myocardial infarction (OR 2.25, 95% CI 1.05-4.80) and heart failure (OR 5.22, 95% CI 1.26-21.64) were associated with incident flutter. In age- and sex-adjusted models, flutter (vs referents) was associated with 10-year increased risk of AF (hazard ratio [HR] 5.01, 95% CI 3.14-7.99), myocardial infarction (HR 3.05, 95% CI 1.42-6.59), heart failure (HR 4.14, 95% CI 1.90-8.99), stroke (HR 2.17, 95% CI 1.13-4.17), and mortality (HR 2.00, 95% CI 1.44-2.79). CONCLUSION: We identified the clinical correlates associated with flutter and observed that flutter was associated with multiple adverse outcomes.

ECG Case of the Month: Unexpected Atrioventricular Conduction in High-Grade Atrioventricular Block. Sinus rhythm; high-grade second degree atrioventricular block with a junctional escape rhythm and three capture complexes, each with right bundle branch block aberration; possible septal myocardial infarct of indeterminate age; ST-T and U wave changes suggesting hypokalemia.

A 90-year-old man with a history of high blood pressure, a cerebrovascular accident without focal residua, dementia, and stage 3 chronic kidney disease went to the emergency department because of dizziness and near syncope. His medications were aspirin 81 mg qd, clopidogrel 75 mg qod, escitalopram oxalate 10 mg qd, Seroquel 25 mg qd, and memantine hydrochloride 10 mg qd. He had orthostatic hypotension with supine blood pressure of 173/77 mm Hg falling to 116/68 on standing, while pulse increased from 66 to 84 beats/ min. He received IV fluid and returned home. Two days later he saw his primary care physician because of episodes of dizziness and confusion. The figure shows an electrocardiogram recorded during that visit.

ECG of the Month. Unexpected Atrioventricular Conduction in High-Grade Atrioventricular Block. DIAGNOSIS: Sinus rhythm; high-grade second-degree atrioventricular block with a junctional escape rhythm and three capture complexes, each with right bundle branch block aberration; possible septal myocardial infarct of indeterminate age; ST-T and U wave changes suggesting hypokalemia.

A 90-year-old man with a history of high blood pressure, a cerebrovascular accident without focal residua, dementia, and stage 3 chronic kidney disease went to the emergency department because of dizziness and near syncope. His medications were aspirin 81 mg qd, clopidogrel 75 mg qod, escitalopram oxalate 10 mg qd, quetiapine fumarate 25 mg qd, and memantine hydrochloride 10 mg qd. He had orthrostatic hypotension with supine blood pressure of 173/77 mmHg falling to 116/68 on standing, while pulse increased from 66 to 84 beats/min. He received IV fluid and returned home. Two days later, he saw his primary care physician because of episodes of dizziness and confusion. The Figure shows an electrocardiogram recorded during that visit.

ECG of the month. Irregular rhythm in a 25-year-old man with three prior cardiac operations. Coarse atrial fibrillation with a rapid ventricular response, left anterior fascicular block, left ventricular hypertrophy with repolarization abnormality.

The patient underwent closure of an atrial septal defect at age 3, had a leaking "mitral" valve repaired at age 9, and at age 13 had a "mitral" valve replacement. He began taking warfarin sodium at that time and remained symptom-free until 10 days before his initial visit here when he presented to another hospital with dyspnea and palpitations. Treatment there consisted of lisinopril 10 mg qd, carvedilol 6.25 mg bid, aldactone 25 mg qd, furosemide 40 mg qd, digoxin 0.25 mg qd, and a continuation of warfarin sodium 7.5 mg qd. An echocardiogram showed a left ventricular ejection fraction of 20%. After diuresis, he was referred to our cardiology clinic. On his initial visit here, his heart rate was an irregular 120 beats/min, his blood pressure was 106/77 mmHg, and closing and opening snaps of a normally functioning mechanical mitral valvular prosthesis were heard. He was obese (height, 5' 9"; weight, 272 lbs). An electrocardiogram was recorded (Figure 1).

Inapparent atrial flutter due to atrial dissociation.

Percutaneous and surgical procedures intended to potentially cure atrial fibrillation require creating lines of conduction block in specific locations throughout the atrial chambers. In patients presenting with recurrent atrial fibrillation, repeat procedures are often performed, resulting in more extensive regions of conduction block and the potential for regions of dissociated atrial rhythms. The present case describes a patient post-multiple ablation procedures who presented with a symptomatic atrial arrhythmia, the mechanism of which was hidden by the presence of extensive atrial dissociation. Electrophysiologic study revealed the appropriate mechanism and a beneficial ablative procedure was then successfully accomplished.

ECG of the month. Bigeminal rhythm VIII. Sinus rhythm with normal antegrade atrioventricular (A-V) conduction and slow retrograde conduction back to the atria, producing atrial reentry or echo complexes and suggesting dual A-V nodal pathways or an accessory A-V pathway that conducts slowly from the ventricles to the atria.

A 55-year-old woman came to the emergency department because of an episode of post-prandial upper abdominal pain radiating to her back and associated with nausea and vomiting. The pain had been recurring intermittently for approximately six months. While in the emergency department, she had another episode of pain and felt lightheaded. Her pulse rate at that point was between 30 and 40 beats per minute, and an electrocardiogram was recorded (Figure).