Cardiovascular Disease: Other Common Arrhythmias.

Premature atrial contractions (PACs) occur in nearly all individuals. Although typically asymptomatic, they can cause palpitations. PACs previously were considered benign, but there is increasing recognition that frequent PACs are associated with developing atrial fibrillation. After potentially reversible causes (eg, electrolyte abnormalities, hyperthyroidism) are eliminated, symptomatic PACs can be treated with beta blockers; some patients are candidates for ablation. Premature ventricular contractions (PVCs) also are common, occurring in more than two-thirds of the population. They typically are asymptomatic, but some patients experience palpitations and dizziness. Persistent PVCs are associated with underlying heart disease; an echocardiogram can help detect this disease. Reversible causes (eg, electrolyte abnormalities, hyperthyroidism, stimulant drug use) should be excluded. Patients with PVCs and left ventricular dysfunction are candidates for ablation. Others may be treated with beta blockers, nondihydropyridine calcium channel blockers, or antiarrhythmics. Supraventricular tachycardia also is common. Hemodynamically unstable patients are treated with cardioversion. Stable symptomatic patients can be considered for catheter ablation or medical antiarrhythmics. Finally, sinus node dysfunction, previously called sick sinus syndrome, causes a variety of rhythm disturbances, including bradycardia, sinus arrest, bradycardia-tachycardia syndrome, and others. Unstable patients are treated with atropine to increase heart rate. Stable patients should discontinue bradycardia-causing drugs, if possible. Some may require a pacemaker.

Cardiovascular Disease: Inflammatory and Infectious Heart Conditions.

Acute pericarditis, the most common inflammatory heart condition, typically is caused by viral infections. Patients have sharp chest pain that improves when leaning forward. Electrocardiogram typically shows widespread ST-segment elevation; echocardiogram may show pericardial effusion; and levels of inflammatory markers may be elevated. Colchicine plus nonsteroidal anti-inflammatory drugs are first-line treatment. Patients with fever, elevated inflammatory marker levels, or pericardial effusion should be hospitalized. Myocarditis also commonly is caused by viruses, although some cases are due to autoimmune or other conditions. Symptoms include chest pain, dyspnea, and fever. Although endomyocardial biopsy is the definitive diagnostic test, most cases are diagnosed based on clinical symptoms, electrocardiogram, echocardiogram, and cardiac markers, plus excluding other conditions. Patients with heart failure should receive guideline-recommended therapy, plus treatment of underlying conditions (eg, autoimmune conditions). Infective endocarditis is caused by infection of cardiac valves, chambers, or intracardiac devices. There are many causative organisms, but Staphylococcus aureus is most common. Fever is the most frequent symptom, although some patients have systemic emboli or heart failure. The modified Duke criteria can aid in diagnosis, which is confirmed by positive blood cultures. Antibiotics are started immediately after obtaining blood cultures, modified based on culture results, and continued for 4 to 6 weeks after first negative culture.

Cardiovascular Disease: Atrial Fibrillation and Atrial Flutter.

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in adults, with lifetime rates of 21% to 33%. There are numerous risk factors, including older age, hypertension, coronary disease, obstructive sleep apnea, diabetes, and others. Patients engaging in lifelong high-endurance exercise also have increased risk. Some organizations recommend screening; others do not. However, many patients identify AF themselves using mobile cardiac monitoring devices, some of which accurately detect the arrhythmia. Patients with AF with hemodynamic instability are treated with immediate synchronized cardioversion. Treatment options for stable patients include scheduled cardioversion, rhythm control with pharmacotherapy, catheter ablation, and rate control with pharmacotherapy. Catheter ablation is increasingly used as first-line therapy, with up to 80% of patients remaining AF-free after one or two ablation treatments, an outcome superior to that with pharmacotherapy. Patients with AF should receive anticoagulation based on the CHA2DS2-VASc (Congestive heart failure, Hypertension, Age 75 years or older [doubled], Diabetes, prior Stroke or transient ischemic attack or thromboembolism [doubled], Vascular disease, Age 65 to 74 years, Sex category) score, and also before and immediately after ablation or cardioversion. It is uncertain whether long-term anticoagulation is needed after successful ablation. Atrial flutter (AFL) is the second most common sustained supraventricular arrhythmia. Patients with AFL are at risk of developing AF, and many recommendations for managing AFL are similar to those for AF. The preferred management for AFL is catheter ablation, with success rates exceeding 90%.

Prediction of Metabolic Syndrome in U.S. Adults Using Homeostasis Model Assessment-Insulin Resistance.

Background: The prevalence of obesity among U.S. adults has risen steadily over recent decades. Consequently, interest in identification of those at greatest metabolic risk necessitates the periodic assessment of underlying population characteristics. Thus, the aim of this study is to assess the efficacy of using insulin resistance (IR) as a predictor of metabolic syndrome (MetS). Methods: We performed a serial, cross-sectional analysis of nationally representative data from the National Health and Nutrition Examination Survey (NHANES). Data included nonpregnant adults who participated in NHANES between 2011 and 2018. IR was estimated using the homeostasis model assessment (HOMA). Optimal HOMA-IR cut points for MetS were identified using receiver operating characteristic curve analysis. Results: Data from 8897 participants representing 222 million individuals were analyzed. The estimated prevalence of MetS was 31.7% (n = 2958; 95% confidence interval 30.1-33.3). The optimal HOMA-IR to discriminate between individuals with and without MetS in the general population was 2.83 (sensitivity = 73.8%; specificity = 73.8%; area under the curve = 0.82). Conclusion: The HOMA-IR is a sensitive and specific method of screening for individuals with MetS. Prospective evaluation of this approach's efficacy in identifying those at risk for progression to MetS is warranted.

Spontaneous Coronary Artery Dissection in a 26-Year-Old-Male Soldier.

Spontaneous coronary artery dissection (SCAD) is an uncommon cause of acute coronary syndromes, which has been gaining increased recognition with the routine use of coronary angiography and intravascular imaging techniques in patients presenting with ST-elevation myocardial infarction. Here we report the case of a healthy, 26-year-old active-duty male presented to Tripler Army Medical Center for evaluation of acute onset and worsening chest pain that occurred shortly after participating in an Army physical fitness test. His initial EKG demonstrated a myocardial injury pattern with ST elevations in leads V1-V4. Invasive angiography revealed thrombotic occlusion of the proximal left anterior descending coronary artery with no evidence of atherosclerotic disease by intravascular ultrasound imaging. SCAD was suspected, and this diagnosis was confirmed after eptifibatide-induced propagation of the dissection plane resulting in recurrence of his index chest pain. To our knowledge, this is the first reported case of SCAD in the active-duty military population. SCAD is a rare, but important, cause of acute coronary syndromes that must be recognized by military providers as it necessarily precludes further military service.

Finding the Dieulafoy's Lesion: A Case of Recurrent Rectal Bleeding in an Immunosuppressed Patient.

A Dieulafoy's lesion (DL) is rare cause of acute gastrointestinal bleeding defined as a vascular abnormality of the submucosa. With a high prevalence for the stomach and upper gastrointestinal tract, it is rarely observed in the lower gastrointestinal tract. Its prevalence is rare accounting for less than 2% of all cases of acute gastrointestinal bleeding. The etiology of DL is unknown. Common comorbidities include cardiovascular disease, kidney disease, diabetes, alcohol abuse, liver disease, and chronic NSAID use. Few cases involving chronic steroid use and immunosuppressive treatment have been reported. The most common diagnostic and treatment modality is endoscopy with refractory cases treated with arterial embolization by angiography. We present a case involving a patient with significant comorbidities on chronic immunosuppression with a life-threatening, massive lower gastrointestinal bleed from a DL in the rectum.

Recurrent Torsades with Refractory QT Prolongation in a 54-Year-Old Man.

BACKGROUND QT prolongation is a common, easily overlooked clinical problem with potentially dire consequences. Drug-induced and congenital forms are not mutually exclusive, but are treated differently. Here, we present a case of cryptogenic underlying congenital long QT syndrome (cLQTS) successfully treated with isoproterenol, a drug contraindicated in most congenital forms of this condition. CASE REPORT We present the case of a 54-year-old man who experienced severe QT prolongation after drug administration followed by recurrent episodes of torsade de pointes (TdP) with subsequent ventricular fibrillation (VF) arrest unresponsive to typical therapy. After failing electrolyte repletion, magnesium, amiodarone, and lidocaine, the patient was started on an isoproterenol drip to achieve a heart rate of at least 90 beats per minute (bpm). Isoproterenol resulted in an immediate near-normalization of his QT interval and cessation of his recurrent TdP. The patient was subsequently found to have a mutation of undetermined significance in the KCNQ1 gene, which is implicated in long QT syndrome type 1 (LQT1). Although isoproterenol is contraindicated in LQT1, our patient had an astonishingly therapeutic benefit. CONCLUSIONS After reviewing the electrophysiology of the delayed rectifier potassium current as it relates to long QT syndrome, we propose a mechanism by which our patient's specific mutation may have allowed him to derive benefit from isoproterenol treatment. We believe that there are patients with variants of LQT1 who can be safely treated with isoproterenol.