- Flashcards
What is hypertension and its associated risks?
Sustained blood pressure >130/90 (normal <120/80). Major risk factors include:
Stroke
Coronary artery disease
Peripheral vascular disease
Heart failure
Chronic kidney disease
What are the two types of hypertension?
Essential (primary): 90-95% of cases, no clear cause.
Secondary: Caused by conditions like kidney disease or pregnancy complications (e.g., pre-eclampsia).
Why is hypertension called the “silent killer”?
It’s generally asymptomatic, even with prolonged elevated blood pressure.
What determines blood pressure?
Blood pressure is the product of:
Heart rate: Controlled by autonomic activity.
Stroke volume: Depends on preload, afterload, and contractility.
Systemic vascular resistance: Reflects vascular tone.
What regulates blood pressure in normotensive and hypertensive states?
Cardiac output
Systemic vascular resistance
Venous capacitance
Intravascular fluid volume (kidney function)
What mechanisms contribute to hypertension?
Genetics and lifestyle factors
Sympathetic nervous system and renin-angiotensin-aldosterone system activation
Endothelial dysfunction and vascular remodeling
What are the first-line treatments for hypertension?
Lifestyle modifications:
Weight loss, physical activity, smoking cessation, low-fat/sodium diet.
Eliminate exogenous agents (e.g., alcohol, oral contraceptives).
Pharmacological strategies:
Diuretics, β-blockers, ACE inhibitors, ARBs, calcium channel blockers.
What is an arrhythmia?
Abnormal electrical activity in the heart, leading to irregular heartbeat.
What is normal sinus rhythm?
Heart rate: 60-100 bpm.
Variations:
Sinus tachycardia: >100 bpm.
Sinus bradycardia: <60 bpm.
What are common causes of arrhythmias?
Impulse formation defects: Ectopic beats or interrupted SA-node automaticity.
Impulse conduction defects:
Conduction block (slowed/blocked impulses).
Re-entry circuits (damaged pathways).
How are arrhythmias classified?
By the site of origin:
SAN/AV node
Atrial
Junctional
Ventricular
What are the four classes of antiarrhythmic drugs?
Class I: Na+ channel blockers (reduce slope and peak of action potential).
Class II: β-blockers (reduce rate and conduction).
Class III: K+ channel blockers (prolong repolarization and action potential duration).
Class IV: Ca2+ channel blockers (reduce rate and conduction).
What does the P wave represent in an ECG?
Atrial depolarization.
What do the QRS and T waves represent in an ECG?
QRS wave: Ventricular depolarization.
T wave: Ventricular repolarization.
What do the PR and QT intervals measure in an ECG?
PR interval: Conduction time from atrium to ventricle.
QT interval: Duration of the ventricular action potential.
What is pump-based hypertension, and in whom is it most often seen?
Increased cardiac output with normal systemic vascular resistance, commonly seen in younger patients with essential hypertension.
How do the kidneys contribute to volume-based hypertension?
Excessive sodium and water retention due to:
Increased renin secretion
Elevated angiotensin II and aldosterone
What causes vascular resistance-based hypertension?
Increased systemic vascular resistance with normal cardiac output, common in the elderly. Factors include:
Endothelial dysfunction
Abnormal response to sympathetic stimulation
How does the neuroendocrine system contribute to hypertension?
Abnormal sympathetic tone regulation
Dysfunctional baroreceptor responses
Overproduction of hormones regulating circulation
What is arteriolosclerosis, and how is it linked to hypertension?
Damage to arterioles due to high blood pressure leads to:
Hyaline arteriosclerosis (plasma protein deposition in vessel walls) which leads to
Vascular remodeling and reduced lumen size
How does hypertension accelerate atherosclerosis?
It increases localized endothelial damage, promoting distinct lesions and the risk of aortic aneurysms.
What lifestyle changes help manage hypertension?
Weight loss
Increased physical activity
Smoking cessation
Low-fat, low-sodium diet
Reducing alcohol and exogenous agents (e.g., contraceptives)
How do diuretics lower blood pressure?
They inhibit sodium and chloride reabsorption, reducing intravascular volume and cardiac output.
What are ACE inhibitors and ARBs, and how do they work?
ACE inhibitors: Prevent conversion of angiotensin I to angiotensin II, reducing vasoconstriction.
ARBs: Block angiotensin II from binding to AT1 receptors, reducing blood pressure and vascular proliferation.
