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