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Physical activity, exercise, and the heart

1 What is the difference between physical activity and exercise? Physical activity is skeletal muscle contraction causing body movement that requires energy use. Exercise is a type of planned physical activity that is performed to attain or maintain physical fitness. Physical activity can be classified metabolically as anaerobic (energy derived in the absence of oxygen) or aerobic (energy derived in the presence of oxygen). Physical activity…

Smoking cessation

1 Why is smoking cessation of fundamental importance in the management of the cardiac patient? Smoking cessation is the most important of the modifiable risk factors for cardiovascular disease. The products of tobacco smoke contribute directly, and distinctly, to the development of atherosclerosis and the adverse consequences that follow ( Box 44.1 ). The benefits of smoking cessation cannot be exaggerated. A rapid and sustained reduction…

Diabetes and cardiovascular disease

1 What is the current global burden of diabetes, and what is its impact on the epidemiology of cardiovascular disease? The International Diabetes Federation has estimated that approximately 1 in 11 adults (415 million adults) has diabetes mellitus globally. The global prevalence is expected to rise to 642 million adults by 2040. Over 90% of these cases of diabetes mellitus are due to type 2 diabetes.…

Hyperlipidemia

1 Who should be screened for dyslipidemias and when should a cholesterol panel be checked? As per the 2018 American College of Cardiology/American Heart Association (ACC/AHA) guidelines, all adults aged 20 years or older should undergo screening with either a fasting or nonfasting lipoprotein profile to document baseline low-density lipoprotein cholesterol (LDL-C) and evaluate atherosclerotic cardiovascular disease (ASCVD) risk (class IB). Testing should include total cholesterol,…

Hypertension

1 What is the prevalence of hypertension in men and women and across various ethnic and racial groups? Hypertension affects over 100 million US adults and more than 1.13 billion adults worldwide. Hypertension is the leading cause of death and disability worldwide and is the most important global risk factor for cardiovascular risk (coronary artery disease and stroke). A greater percentage of men (47%) has high…

Cardiac arrest and resuscitation

1 What is the first step to do if you are alone and come across an unresponsive adult victim with no signs of breathing? Activate an emergency response system and get an automated external defibrillator (AED) if available in the area and then return to the victim. If you return with an AED, turn it on and follow the prompt. If no AED is available, check…

Implantable cardioverter defibrillators

1 What are the components of an implantable cardioverter defibrillator (ICD)? Implantable cardioverter defibrillators (ICDs) are composed of a pulse generator (typically implanted in the left upper chest) and one or more leads. The generator is composed of the electrical circuitry, a battery, and capacitors. It uses nonrechargeable lithium-based batteries that are reliable energy sources with a good safety profile and predictable life expectancy. The internal…

Cardiac pacing for bradycardia, conduction abnormalities, and heart failure

1 What is sick sinus syndrome? Sinus node dysfunction, commonly referred to as sick sinus syndrome, refers to a broad array of abnormalities of the sinus node, ranging from atrial impulse formation through propagation of the depolarization impulse. Sick sinus syndrome can manifest as sinus bradycardia, paroxysmal sinus arrest, sinus node exit block, or chronotropic insufficiency. Tachycardia-bradycardia (“tachy-brady”) syndrome is a common association between sick sinus…

Ventricular arrhythmias

1 What is the differential diagnosis of a wide complex tachycardia? A wide complex tachycardia (WCT) is a heart rate greater than 100 beats/min, with a QRS duration greater than 120 milliseconds, and the differential includes: Ventricular tachycardia (VT) (monomorphic or polymorphic). Atrial fibrillation, atrial flutter, or supraventricular tachycardia (SVT) with aberrant conduction (either fixed or rate-related bundle branch block). Antidromic atrioventricular (AV) reentrant tachycardia (Wolff-Parkinson-White…

Supraventricular tachycardia

1 What does the term supraventricular tachycardia mean? By strict definition, supraventricular tachycardia (SVT) is any nonphysiological tachycardia with rates in excess of 100 beats/min, whose genesis involves tissue from above the bifurcation of the His bundle. Thus the term can encompass inappropriate sinus tachycardia (IST), atrial tachycardia (AT) (focal and multifocal), macroreentrant AT (such as typical atrial flutter), junctional tachycardia, atrioventricular (AV) nodal reentrant tachycardia…

Atrial fibrillation

1 What is the difference between atrial fibrillation and atrial flutter? Atrial fibrillation (AF) is a supraventricular tachyarrhythmia with uncoordinated atrial activation and consequently ineffective atrial contraction with electrocardiogram (ECG) characteristics of (1) irregular R-R intervals (when atrioventricular [AV] conduction is present), (2) absence of distinct repeating P waves, and (3) irregular atrial activity ( Fig. 35.1 ). On the other hand, atrial flutter is characterized…

Endocarditis and endocarditis prophylaxis

1 What are believed to be the first steps in the development of infective endocarditis? Infective endocarditis (IE) is believed to occur only after one first develops what is termed nonbacterial thrombotic endocarditis (NBTE). According to the American Heart Association (AHA) statement on endocarditis, it is believed that turbulent blood flow produced by certain types of congenital or acquired heart disease traumatizes the endothelium. This turbulent…

Transcatheter aortic valve replacement

1 What is transcatheter aortic valve replacement? Transcatheter aortic valve replacement (TAVR, alternately known as transcatheter aortic valve implantation [TAVI]) is a procedure in which a diseased aortic valve is replaced via an endovascular or transthoracic approach, using a bioprosthetic valve delivered via a catheter ( Figs. 33.1 and 33.2 ). Traditionally, TAVR has been used to ameliorate severe aortic stenosis (AS). It stays in position…

Mitral stenosis

1 What is mitral stenosis? Mitral stenosis (MS) comprises any anatomical obstruction at the level of the mitral valve apparatus causing resistance to left ventricular (LV) filling during diastole. 2 What is the usual cause of mitral stenosis? Most cases of MS arise as a chronic sequel to rheumatic fever, the autoimmune inflammatory processes secondary to group A β-hemolytic streptococcal pharyngitis. This is characterized by fibrocalcific…

Mitral regurgitation

1 What are the causes of mitral regurgitation? There are two broad categories of mitral regurgitation (MR), primary and secondary. In primary MR, disease of the mitral valve causes it to leak, imparting a volume overload on the left ventricle (LV). The most common causes of primary MR include mitral valve prolapse (MVP) from myxomatous disease, calcific degeneration, infective endocarditis, rheumatic heart disease, and collagen vascular…

Aortic regurgitation

1 What is aortic regurgitation? Aortic regurgitation (AR) occurs when an incompetent aortic valve (AV) allows blood initially ejected from the left ventricle (LV) to the aorta to return to the LV during diastole. 2 What are the causes of acute aortic regurgitation? Acute AR may result from either abnormalities of the valve cusps or aortic root. Abnormalities of the valve cusps that may lead to…

Aortic stenosis

1 What is the prevalence of aortic stenosis? What are the trends in aortic stenosis with age? Aortic stenosis (AS) ( Fig. 29.1 ) is the second most common valvular heart disease in the community, and the most frequent single-valve disease referred to the hospital. It has been estimated to occur in 0.3% to 0.5% of the general population and 2% to 7% of individuals older…

Heart transplantation

1 How many heart transplants are performed in the United States each year? Dr. Christiaan Barnard performed the first human allograft transplant in 1967. Approximately 3000 heart transplants now occur each year, most commonly for nonischemic cardiomyopathy (51%) and coronary artery disease (CAD; 32%) and less commonly for congenital heart disease, valvular heart disease, and other indications, including retransplantation. There has been a slight increase in…

Heart failure: Long-term management

This chapter addresses the long-term management of patients with chronic heart failure with reduced (depressed) ejection fraction (HFrEF). The management of patients with heart failure with preserved ejection fraction (HFpEF) is discussed in Chapter 23 . The management of patients with acute decompensated heart failure is discussed in Chapter 26 . Specific discussions of left ventricular assist devices (LVADs) and consideration of cardiac transplantation are discussed…

Acute decompensated heart failure

1 What is acute decompensated heart failure? Isn’t it just a worsening of chronic heart failure? Acute decompensated heart failure (ADHF) is a clinical syndrome of worsening signs or symptoms of heart failure (HF) requiring hospitalization or other unscheduled medical care. For many years, ADHF was viewed as simply an exacerbation of chronic HF as a result of volume overload, with few implications beyond a short-term…