This chapter presents the anatomy review of the human heart. The human heart is a hollow four-chambered muscle that is responsible for pumping blood throughout the body. The heart lies in the mediastinum in the thorax, pointing toward the left of the midline. The heart consists of four main layers: the pericardium, epicardium, myocardium, and endocardium. The epicardium is the outermost layer of the heart muscle. The middle layer of the heart is called the myocardium. The innermost layer of the heart is the endocardium. The heart is divided into right and the left side. The right side of the heart contains the right atrium and right ventricle. The left side of the heart contains the left atrium and left ventricle. The heart has four valves: tricuspid valve, mitral valve, aortic valve, pulmonary valve; acting as tiny doors that keep the blood moving in one direction.
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The chapter explores how to measure the electrical direction for the P wave, the QRS complex, and the T wave, as well as for other forces. It provides a method for determining the direction of the electrical force for any of these waves, or complexes, on the electrocardiograph (EKG). The heart produces electrical and mechanical energy on a continuous basis. Both forms of energy come from specialized cardiac muscle fibers. These fibers provide electrical signals and mechanical energy that physically pumps the blood. Although the EKG does not show that mechanical energy, it can be used to measure a variety of electrical events. When a force is abnormal in size or direction, it may indicate that the specific part of the heart producing the force is abnormal. Therefore, learning the normal electrical direction of forces in the heart provides a simple and scientific way of understanding and interpreting an EKG.
This chapter explains various types of heart blocks such as premature atrial contraction, sinus arrest and asystole. It explains various types of pacemakers such as ventricular pacemaker and artrial pacemakers. Junctional rhythm is a regular rhythm. A P wave is frequently not seen because the rhythm originates in the AV junctional node. Junctional rhythm may be a manifestation of digitalis toxicity, sick sinus syndrome, and acute inferior wall infarction. Pauses are most commonly caused by premature atrial contractions (PACs) that do not conduct down to the ventricle and generate a QRS complex. These are called nonconducted PACs (NCPACs). Asystole is a prolonged period of no electrical activity. Cessation of function of the sinus node is called sinus arrest. Normally, when sinus arrest occurs, another pacemaker must take over, such as the junction or the ventricles. Ventricular pacemaker rhythm demonstrates a vertical electrical artifact (EA) at the beginning of the QRS.
This chapter presents the case examples of pressure and volume overload on the left ventricle and provides list of criteria for the diagnosis of Left Ventricular Hypertrophy (LVH) on the electrocardiogram (EKG). It also describes and explains how to identify ST changes in LVH and LVH simulating anterior wall infarction on the EKG. LVH refers to an increase in the wall thickness or dilation of the left ventricle. LVH is often the result of increased pressure, or volume, within the left ventricular chamber. Mitral regurgitation (MR) occurs when the mitral valve allows the backflow of blood from the left ventricle into the left atrium. The most common cause of pressure overload is hypertension (HTN). Hypertrophy of the left ventricle increases the amplitude of the left ventricular forces, because more mass generates more electricity. In LVH, the frontal plane, the horizontal plane, or both may show increased QRS amplitude.
In the postpartum period, secondary postpartum hemorrhage (SPPH) and endometritis are two conditions that frequently present to an obstetric triage unit. These complications may coexist and can occur from 24 hours postpartum to 6 weeks postdelivery. SPPH is typically not as severe as a primary bleeding episode. Postpartum women ultimately diagnosed with endometritis are generally stable, but less commonly can present in septic shock. This chapter discusses presenting symptomatology, history and data collection, physical examination, laboratory and imaging studies, differential diagnosis, and clinical management and follow-up of secondary postpartum hemorrhage and postpartum endometritis. Prompt treatment of both SPPH and postpartum endometritis can reduce maternal morbidity and mortality. SPPH is managed with the same guiding principles as primary postpartum hemorrhage. Initial treatment for postpartum endometritis is intravenous clindamycin and gentamicin.
Pregnant women presenting with abdominal pain to an emergency department or obstetric triage setting frequently have a diagnostic ultrasound (US) to assess fetus, placenta, and adnexae. In the first trimester, symptomatic adnexal masses typically present with unilateral or bilateral pelvic cramping or pressure. Obtaining a history in a pregnant woman with abdominal pain is similar to doing so for the nonpregnant patient. In addition to routine cardiopulmonary examination, abdominal examination, and assessment for costovertebral angle tenderness, a sterile speculum and vaginal examination are performed to evaluate for adnexal or uterine tenderness, cervical dilation, and potential rupture of membranes. If a mass is suspected, US is the preferred imaging modality. Magnetic resonance imaging can be employed if additional imaging is needed. Differential diagnosis of abdominal pain in pregnant women must include other obstetric and nonobstetric causes of pain. This chapter describes clinical management and follow-up of pregnant women with adnexal masses.
Maternal sepsis is a common pregnancy-related condition; in the United States, it is a leading cause of maternal mortality, accounting for up to 28” of maternal deaths and up to 15” of maternal admissions to the intensive care unit. One contributing and modifiable factor to these deaths is failure to recognize sepsis, leading to delays in treatment. Therefore, rapid and accurate diagnosis and initial management of sepsis in pregnancy in the emergency department (ED) is paramount. Pregnancy poses a unique challenge given the baseline physiologic changes and the need to care for the mother while simultaneously caring for the fetus. Therefore, without clear pregnancy-specific data, recommendations are to follow the current guidelines for nonpregnant adults, yet be cognizant of the ways in which pregnancy may change maternal physiology and affect fetal well-being. Prompt identification and treatment of maternal sepsis will undoubtedly lead to the best possible maternal and neonatal outcomes.
Intimate partner violence (IPV) and sexual assault are common violent crimes perpetrated on women. Obstetric (OB) complications associated with trauma include miscarriage, preterm labor, and placental abruption. Ongoing mental health issues, including depression and anxiety, are more prevalent in pregnant women subjected to any form of IPV, whether or not direct physical violence is involved. One study showed that pregnant women subjected to verbal threats were twice as likely to deliver low-birth-weight infants. All women who present to an OB triage unit or an emergency department (not just those who present with an injury or complication) must be screened for IPV. An organized plan for providing the victim with resources must be readily available when a screen is positive. This chapter discusses presenting symptomatology, history and data collection, physical examination, laboratory and imaging studies, differential diagnosis, clinical management and follow-up care of IPV and sexual assault.
The goal of this book is to teach the ability to form an autonomous and clinically useful opinion about any 12-lead electrocardiogram (EKG). It introduces basic principles of anatomy and physiology, including a review of the heart’s electrical system. The heart has an intricate electrical system, made up of highly specialized cells, that is responsible for generating each heart beat. The heart’s electrical system consists of five structures: the sinoatrial (SA node), the atrioventricular (AV node), the bundle of His, the right and left bundle branches, and the Purkinje fibers. One of the most basic yet important pieces of information the EKG provides is the heart rate (HR). The most accurate way to measure heart rate is by measuring the R-R interval. Learning the normal electrical direction of forces in the heart provides a simple and scientific way of understanding and interpreting an EKG. The book also discusses vital elements of cardiology, such as atrial and ventricular arrhythmias, conduction abnormalities and heart block, ischemic and nonischemic disorders, and more. It explains various types of heart blocks such as premature atrial contraction, sinus arrest and asystole, and various types of pacemakers such as ventricular pacemaker and artrial pacemakers. Drug effects and toxicities, electrolyte imbalances, trauma, pericardial diseases, lung disease, cancer, cardiomyopathies, and systemic diseases are conditions that can cause specific changes on the EKG.