IM8.{1-8,10-19} | Hypertension — Glossary

A class of antihypertensive agent that blocks the conversion of angiotensin I to angiotensin II; reduces BP and provides nephroprotection (reduces proteinuria) in diabetes and CKD; common side effect: dry cough (bradykinin accumulation); contraindicated in pregnancy and bilateral renal artery stenosis.

Automated 24-hour BP recording during normal daily activities; the gold standard for diagnosing white-coat and masked hypertension; also assesses nocturnal dipping (non-dipping = increased cardiovascular risk).

The principal effector hormone of the RAAS; causes direct vasoconstriction via AT1 receptors, stimulates aldosterone release, promotes cardiac and vascular hypertrophy, and activates the sympathetic nervous system.

A class of antihypertensive agent that blocks the AT1 receptor of angiotensin II; similar efficacy and indications to ACE inhibitors but without the bradykinin-mediated dry cough; preferred alternative when ACE inhibitor cough occurs.

Atherosclerotic cardiovascular disease 10-year risk, estimated using the Pooled Cohort Equations (PCE) or Framingham risk score; risk >10% in Stage 1 hypertension (ACC/AHA) is the threshold for initiating drug therapy alongside lifestyle modification.

The intrinsic mechanism by which cerebral blood flow is maintained constant over a wide range of perfusion pressures; in chronically hypertensive patients, the autoregulatory curve shifts rightward, meaning the brain requires higher perfusion pressures to maintain adequate flow — explaining why BP must be reduced gradually in hypertensive emergency.

Risk stratification score for stroke in atrial fibrillation: C=Congestive HF (1), H=Hypertension (1), A=Age≥75 (2), D=Diabetes (1), S=Stroke/TIA (2), V=Vascular disease (1), A=Age 65–74 (1), Sc=Sex category female (1); score ≥2 in men or ≥3 in women = anticoagulation recommended.

A comorbid condition for which a specific antihypertensive drug class has proven outcome benefit beyond BP lowering alone, making it the preferred or mandated choice; examples: ACE inhibitor/ARB for diabetes + microalbuminuria; beta-blocker for HFrEF; CCB for Raynaud phenomenon.

ECG criteria for LVH: R in aVL + S in V3 >28 mm in men or >20 mm in women; complementary to Sokolow-Lyon, with slightly different sensitivity/specificity characteristics.

Dietary Approaches to Stop Hypertension; an evidence-based dietary pattern emphasising fruits, vegetables, low-fat dairy, and reduced sodium and saturated fat; proven to reduce systolic BP by 8–14 mmHg in clinical trials; the dietary cornerstone of non-pharmacological hypertension management.

A subclass of CCBs (amlodipine, nifedipine, felodipine) that primarily dilates peripheral arterioles by blocking vascular smooth muscle L-type calcium channels; first-line in elderly, isolated systolic hypertension, and Black patients; key side effect: peripheral ankle oedema.

Estimated kidney filtration capacity calculated from serum creatinine, age, and sex using the CKD-EPI or MDRD formula; must be calculated in all hypertensive patients as serum creatinine alone underestimates GFR loss (especially in elderly, women, and malnourished patients).

Hypertension without an identifiable single cause; accounts for 90–95% of all cases; results from interactions among genetic predisposition, dietary sodium excess, obesity, sedentary lifestyle, and ageing.

A non-atherosclerotic, non-inflammatory disease of medium-sized arteries (commonly renal, internal carotid); causes renovascular hypertension in young women; characteristic 'beading' on renal arteriography; high success rate with angioplasty.

A single tablet containing two or more antihypertensive agents at fixed doses; improves adherence by reducing pill burden; examples include amlodipine + telmisartan, ramipril + amlodipine, losartan + hydrochlorothiazide; strongly preferred over multiple separate tablets for most patients.

Measurement of BP by the patient at home using a validated automated device; used to diagnose white-coat and masked hypertension, and to monitor treatment; two readings morning and evening for 7 days, average of last 6 days used.

A sustained elevation of systemic arterial blood pressure above a threshold associated with increased cardiovascular, cerebrovascular, and renal risk; defined as ≥130/80 mmHg (ACC/AHA 2017) or ≥140/90 mmHg (JNC 7 / IGH-IV 2019).

Severe elevation of blood pressure WITH evidence of acute end-organ damage (encephalopathy, stroke, ACS, pulmonary oedema, aortic dissection, AKI, papilloedema, eclampsia); requires IV antihypertensive therapy with controlled MAP reduction ≤20–25% in the first hour.

Acute cerebral oedema due to breakthrough autoregulation failure from severely elevated BP; manifests as headache, confusion, seizures, and visual disturbance; associated with posterior reversible encephalopathy syndrome (PRES) on MRI.

Severe elevation of blood pressure (usually >180/120 mmHg) WITHOUT evidence of acute end-organ damage; managed with gradual BP reduction over 24–48 hours using oral agents.

Systolic BP ≥140 mmHg with diastolic BP <90 mmHg; common in the elderly due to aortic stiffness and increased pulse wave velocity.

Classification of hypertensive retinopathy: Grade I = mild arteriolar narrowing (silver wiring); Grade II = AV nicking; Grade III = flame haemorrhages and cotton-wool spots; Grade IV = papilloedema. Grades III–IV = hypertensive emergency.

A combined alpha-1 and non-selective beta-adrenergic blocker given intravenously in hypertensive emergency; reduces both BP and heart rate; the preferred IV agent for aortic dissection, hypertensive encephalopathy, and eclampsia; onset 5–10 min, duration 3–6 hours.

Conduction block of the anterior fascicle of the left bundle branch; ECG: left axis deviation ≥-45° (some criteria ≥-30°), small q wave in I and aVL, small r wave in II/III/aVF, normal QRS duration; common in LVH and hypertensive heart disease.

Concentric thickening of the left ventricular wall in response to chronic pressure overload (elevated afterload); the most important cardiac target organ damage of hypertension; identified by ECG (Sokolow-Lyon: S-V1 + R-V5/V6 >35 mm) or echocardiography.

A rare autosomal dominant monogenic form of hypertension caused by a gain-of-function mutation in the beta or gamma subunit of the epithelial sodium channel (ENaC), leading to excessive renal sodium reabsorption, volume expansion, and suppressed renin and aldosterone levels.

ST depression with asymmetric T-wave inversion in the lateral leads (I, aVL, V5-V6) occurring in the context of LVH voltage criteria; indicates subendocardial ischaemia from pressure-overload and confers significantly elevated cardiovascular risk beyond LVH voltage alone.

Normal BP in the clinic but elevated out-of-clinic BP on HBPM or ABPM; often missed; carries similar cardiovascular risk to sustained hypertension and requires treatment.

Average arterial pressure throughout a cardiac cycle; approximated as diastolic BP + 1/3 pulse pressure, or (SBP + 2×DBP)/3; the target in hypertensive emergency management is to reduce MAP by no more than 20–25% in the first hour (except aortic dissection).

Urinary albumin excretion 30–300 mg/day or urine albumin-to-creatinine ratio (ACR) 30–300 mg/g; the earliest marker of hypertensive renal involvement; also an independent cardiovascular risk marker.

An intravenous dihydropyridine calcium channel blocker used in hypertensive emergency; smooth and titratable; preferred for hypertensive encephalopathy, perioperative hypertension, and acute ischaemic stroke (pre-tPA); onset 5–10 min.

Recurrent upper airway obstruction during sleep causing hypoxia and arousal; triggers nocturnal sympathetic activation, raises 24-hour mean BP, and is a common secondary contributor to hypertension and resistant hypertension; treated with CPAP which lowers BP.

A fall of ≥20 mmHg in systolic or ≥10 mmHg in diastolic BP within 3 minutes of standing from supine position; common in elderly hypertensive patients and those on diuretics or vasodilators; increases fall risk and must be checked before initiating antihypertensives in older patients.

ECG sign of left atrial enlargement: P wave duration >120 ms (>3 small boxes), notched bifid appearance in lead II, negative terminal deflection in V1 ≥1 mm deep and ≥40 ms wide; reflects elevated left atrial pressure from diastolic dysfunction or mitral regurgitation.

A randomised crossover trial showing that spironolactone (25–50 mg/day) is significantly more effective than bisoprolol or doxazosin as a fourth antihypertensive agent in patients with resistant hypertension; supports the hypothesis that resistant hypertension is frequently volume-dependent or aldosterone-mediated.

A catecholamine-secreting tumour of the adrenal medulla; classic triad: episodic headache, palpitations, and diaphoresis; diagnosed by 24-hour urinary metanephrines; alpha-blockade must precede beta-blockade to prevent paradoxical hypertension crisis.

First-line screening test for primary aldosteronism; an elevated ARR indicates autonomous aldosterone excess suppressing renin; further confirmed by saline or fludrocortisone suppression test.

Autonomous excess aldosterone secretion independent of renin; presents as hypertension with spontaneous or diuretic-exacerbated hypokalaemia; screened by plasma aldosterone-to-renin ratio (ARR); commonest secondary cause of hypertension (5–10% of HTN).

Apparent treatment failure in hypertension due to non-pathological causes: white-coat effect (elevated in clinic only), medication non-adherence, inadequate drug doses, suboptimal drug choices, or large-cuff error; must be excluded before labelling hypertension as truly resistant.

A delay in the femoral pulse relative to the radial pulse on simultaneous palpation; the hallmark physical examination sign of coarctation of the aorta, in which the narrowed aorta causes reduced and delayed blood flow to the lower limbs.

A hormonal cascade in which renin (from renal juxtaglomerular cells) cleaves angiotensinogen to angiotensin I, ACE converts it to angiotensin II, which raises BP via vasoconstriction and aldosterone-mediated sodium retention.

Blood pressure that remains above goal despite concurrent use of ≥3 antihypertensive agents at optimal doses, including a diuretic; requires systematic evaluation for secondary causes, medication non-adherence, and white-coat effect.

Hypertension with an identifiable, potentially reversible or specifically treatable cause; accounts for 5–10% of adult hypertension and up to 20–30% in young, resistant, or hypokalaemic patients.

A direct arteriovenous vasodilator used in severe hypertensive emergencies requiring rapid, titratable BP reduction; immediate onset (<1 min), very short duration; risk of cyanide toxicity with prolonged use or in renal failure; must be given in ICU with intra-arterial monitoring.

ECG criteria for left ventricular hypertrophy: S wave in V1 plus R wave in V5 or V6 >35 mm in adults (age-adjusted thresholds apply in those under 35); a standard screen for hypertensive cardiac target organ damage.

An aldosterone antagonist that blocks mineralocorticoid receptors in the distal nephron; reduces sodium retention and lowers BP; proven as the most effective fourth agent for resistant hypertension (PATHWAY-2 trial); particularly effective in primary aldosteronism and volume-dependent hypertension.

Systolic blood pressure 130–139 mmHg or diastolic blood pressure 80–89 mmHg, as per the 2017 ACC/AHA guideline.

Systolic blood pressure ≥140 mmHg or diastolic blood pressure ≥90 mmHg, as per the 2017 ACC/AHA guideline.

Structural or functional injury to end-organs (heart, brain, kidneys, retina, large vessels) caused by sustained elevated blood pressure; presence of TOD upgrades cardiovascular risk to 'very high' and mandates intensive BP control.

A diuretic class (indapamide, chlorthalidone) that inhibits the renal Na-Cl cotransporter; preferred over hydrochlorothiazide for cardiovascular outcome evidence (ALLHAT); side effects include hypokalaemia, hyperuricaemia, and glucose intolerance.

The methylated metabolites of catecholamines (metanephrine and normetanephrine) excreted in the urine; 24-hour urinary metanephrines and plasma fractionated metanephrines are the most sensitive screening tests for phaeochromocytoma.

Elevated BP readings in a clinical setting with normal out-of-clinic BP on home monitoring (HBPM) or 24-hour ambulatory BP monitoring (ABPM); prevalence ~15-20%; carries intermediate cardiovascular risk between true normotension and sustained hypertension.