Endocardium
Inner lining of the heart chambers and valves
Myocardium
Muscular middle layer of the heart responsible for contraction
Epicardium
Outer layer of the heart wall
SA node
Primary pacemaker of the heart initiating electrical impulses
AV node
Delays impulse to allow atrial contraction before ventricular contraction
Bundle of His
Electrical pathway transmitting impulses from AV node to ventricles
Purkinje fibers
Network distributing impulse throughout ventricles for coordinated contraction
P wave on ECG
Atrial depolarization
QRS complex on ECG
Ventricular depolarization
T wave on ECG
Ventricular repolarization
Cardiac output
Amount of blood pumped per minute equal to heart rate times stroke volume
Stroke volume
Amount of blood ejected from ventricle each beat
Blood pressure determinants
Cardiac output blood volume and peripheral resistance
Electrocardiogram ECG
Records electrical activity of the heart and detects arrhythmias or infarction
Echocardiogram
Ultrasound imaging showing heart structure valve movement and blood flow
Angiography
Imaging using contrast dye to visualize coronary arteries and blockages
Stress test
Evaluates heart function during exercise to detect ischemia
Cardiac biomarkers
Troponin and other enzymes released during myocardial damage
Lifestyle changes for cardiovascular disease
Weight loss exercise smoking cessation reduced salt reduced saturated fat stress control
Vasodilators
Drugs that relax blood vessels reducing peripheral resistance and blood pressure
Beta blockers
Drugs that decrease heart rate contractility and blood pressure
Calcium channel blockers
Drugs that reduce myocardial contractility and vascular resistance
ACE inhibitors
Drugs that block angiotensin II formation lowering blood pressure
Diuretics
Drugs that increase urine output reducing blood volume and blood pressure
Anticoagulants
Drugs that prevent clot formation
Statins
Drugs that lower LDL cholesterol and reduce atherosclerosis risk
LDL cholesterol
Transports cholesterol to tissues and promotes plaque formation
HDL cholesterol
Removes cholesterol from tissues and transports it to the liver for removal
Atheroma
Fatty plaque composed of lipids fibrous tissue and inflammatory cells in arterial wall
Metabolic syndrome
Cluster including obesity insulin resistance hypertension and dyslipidemia increasing cardiovascular risk
Angina pectoris
Chest pain caused by temporary myocardial ischemia without tissue death
Stable angina
Chest pain triggered by exertion relieved by rest or nitroglycerin
Myocardial infarction
Prolonged coronary obstruction causing myocardial tissue necrosis
MI classic symptoms
Severe crushing chest pain radiating to arm neck or jaw dyspnea nausea sweating anxiety
MI diagnostic markers
Elevated cardiac troponin abnormal ECG changes
Sinus bradycardia
Heart rate below normal due to slowed SA node firing
Sinus tachycardia
Heart rate above normal due to increased SA node firing
Atrial fibrillation
Rapid chaotic atrial impulses producing irregular ventricular rhythm and clot risk
Atrial flutter
Rapid regular atrial contractions often producing tachycardia
Heart block
Impaired conduction between atria and ventricles
Third degree heart block
Complete dissociation between atrial and ventricular activity
Premature ventricular contraction
Early ventricular beat originating outside SA node
Ventricular tachycardia
Rapid ventricular rhythm that may reduce cardiac output
Ventricular fibrillation
Chaotic ventricular electrical activity causing loss of effective pumping and death if untreated
Cardiac arrest
Complete cessation of effective cardiac activity and circulation
Congestive heart failure
Heart unable to pump sufficient blood to meet body needs
Common causes of CHF
Coronary artery disease hypertension myocardial infarction valve disease cardiomyopathy
Forward effects of CHF
Reduced perfusion causing fatigue hypoxia and organ dysfunction
Left sided heart failure
Backflow into pulmonary circulation causing pulmonary edema dyspnea cough orthopnea
Right sided heart failure
Backflow into systemic veins causing peripheral edema hepatomegaly ascites jugular distention
Pulmonary edema
Fluid accumulation in lungs impairing oxygen exchange
Orthopnea
Difficulty breathing when lying flat relieved by sitting upright
Essential hypertension
Persistent elevation of systemic blood pressure without identifiable secondary cause
Hypertension mechanism
Increased peripheral resistance from arteriolar vasoconstriction
Hypertension early stage
Often asymptomatic called silent disease
Hypertension long term effects
Damage to heart kidneys brain and retina
Hypertension risk factors
Age genetics obesity high salt intake smoking alcohol stress sedentary lifestyle
Hypovolemic shock
Shock caused by major loss of blood or fluid leading to reduced circulating volume
Cardiogenic shock
Shock due to severe heart failure preventing adequate cardiac output
Septic shock
Distributive shock caused by systemic infection producing vasodilation and hypotension
Anaphylactic shock
Severe allergic reaction causing widespread vasodilation airway constriction and hypotension
Neurogenic shock
Loss of sympathetic vascular tone causing widespread vasodilation and hypotension
Early shock signs
Anxiety tachycardia pale cool skin sweating decreased urine output
Progressive shock effects
Metabolic acidosis organ failure renal failure ARDS DIC
Compensatory shock response
Vasoconstriction increased heart rate and fluid retention to maintain perfusion