Blood Pressure and Flow in the Heart

• Hypertension and drug therapy are important topics in managing cardiovascular health.
• Mechanical System

Systole and Diastole

• Systole is the contraction of the heart muscle.
• Diastole is the relaxation of the heart muscle.

Cardiac Output

• Cardiac output (CO) is the amount of blood pumped by each ventricle in one minute.
• CO is the product of stroke volume (SV) and heart rate (HR).

Blood Pressure

• Blood pressure is influenced by cardiac output and systemic vascular resistance.
• Systemic vascular resistance is impacted by the dilation of blood vessels, with increased dilation leading to decreased resistance.

Blood Flow Through The Heart

• Blood flows through the heart in the following sequence:
  • superior vena cava and inferior vena cava
  • right atrium (1)
  • tricuspid valve (2)
  • right ventricle
  • pulmonary valve -pulmonary artery (6)
  • in to lungs
  • pulmonary veins
  • left atrium (3)
  • mitral valve (4)
  • left ventricle (5)
  • aortic valve
  • aorta to body

Hypertension Guidelines

• Blood pressure management is based on four stages of measurements: normal, elevated, Stage I, Stage II, and hypertensive crisis.
• Elevated systolic blood pressure (SBP) has strong associations with heart failure, stroke, and renal failure.
• "Prehypertensive" blood pressures are no longer considered "high normal".
• Lifestyle modifications are required to prevent cardiovascular disease.
• Thiazide-type diuretics are the initial drug therapy for most patients.
• Thiazide-type diuretics reduces volume of blood being pumped.

Etiology of Hypertension

• Primary (essential/idiopathic) hypertension is elevated BP without an identifiable cause
• This accounts for 90% to 95% of all cases.
• Factors contributing to primary hypertension includes sodium-retaining hormones,diabetes mellitus, a high sodium intake, excessive alcohol intake, and being above ideal body weight.

Risk Factors for Primary Hypertension

• Risk factors include age, becoming more rigid with age, alcohol use, cigarette smoking, diabetes mellitus, elevated serum lipids, excess dietary sodium, as well as gender, family history, obesity, ethnicity, sedentary lifestyle, socioeconomic status, and stress.

Pathophysiology of Hypertension

• Genetic factors contribute less to BP levels in the general population.
• Stress and increased SNS activity generates increased vasoconstriction.
• Increased heart rate.
• Increased Renin release.

Water and Sodium Retention

• High sodium intake activates pressor mechanisms and resulting in water retention.
• Certain demographics shows an association with "salt sensitivity."
  • Obesity
  • Increasing age
  • African American ethnicity

More Hypertension Etiology

• Secondary hypertension is elevated BP with a specific cause.
• It accounts for 5% to 10% of adult cases.
• Contributing factors include coarctation of aorta, renal disease, endocrine disorders, hormone imbalances, neurologic disorders, cirrhosis, and sleep apnea.

Hypertension Clinical Manifestations

• Development is insidious because patients are asymptomatic until organ disease occurs.
• Symptoms are secondary to target organ disease and can include fatigue, reduced activity tolerance, dizziness, palpitations, angina, and dyspnea.

Hypertension Complications

• Target organ diseases most frequently occur in the heart, brain, peripheral vasculature, kidney, and eyes.

Hypertension Heart Disease

• Hypertensive heart disease can cause coronary artery disease, left ventricular hypertrophy, and heart failure.

Hypertension Collaborative Care

• Overall goals are to control blood pressure and reduce CVD risk factors.
• Drug therapy acts to treat hypertension.
• Primary action mechanisms are to reduce systemic vascular resistance and the volume of circulating blood.

Antihypertensive Drug Categories

• The categories include diuretics, adrenergic drugs, angiotensin converting enzyme (ACE) inhibitors, angiotensin II receptor blockers (ARBs), calcium channel blockers (CCBs), direct renin inhibitors, and vasodilators.

Diuretics

• Diuretics decreases plasma and extracellular fluid volumes.
• Decreased preload, cardiac output, and total peripheral resistance happens as the result.
• There is decreased workload on the heart and decreased blood pressure as the overall effect.

Thiazide Diuretics

• Hydrochlorothiazide is a prototype.
• It is a first-line hypertension treatment.
• On the distal convoluted tubule of kidney is the site of action.
• Sodium, potassium, and chloride reabsorption is inhibited.
• There is an osmotic water loss.
• It directly relaxes the small blood vessels which reduces peripheral vascular resistance (afterload).
• Used to treat hypertension, heart failure, edema, hypercalciuria, and diabetes insipidus, drug allergies, anuria, and renal failure are among the contraindications.

Thiazide Diuretics Adverse Effects

• CNS adverse effects: dizziness, headache, blurred vision, paresthesia.
• GI adverse effects: anorexia, nausea, vomiting, diarrhea, pancreatitis, cholecystitis.
• GU adverse effects: decreased libido and impotence (sexual activity).
• Hematologic adverse effects: jaundice, leukopenia, purpura, thrombocytopenia.
• Integumentary adverse effects: urticaria, photosensitivity.
• Metabolic adverse effects: hypokalemia, glycosuria, hyperglycemia, hyperuricemia.
• With toxicity, overdose can cause severe hypokalemia with symptoms like lethargy, weakness, confusion and hypotension.

Adrenergic Drugs

• Adrenergic drugs bind to adrenergic receptors.
• They inhibit the sympathetic nervous system.
• Types of adrenergic drugs include alpha-blockers and beta-blockers.
• Drugs are classified by the adrenergic receptor they block.
  • Alpha1 and alpha2 receptors.
  • Beta1 and beta2 receptors.
• Multiple sub-groups can cause drowsiness and sedation.
• Centrally acting alpha2 agonists are used.
• Peripherally acting alpha adrenergic blockers are used.
• Beta Blockers.

Adrenoceptors

• α1 generates vasoconstriction, increased peripheral resistance, increased blood pressure, and mydriasis.
• α2 blocks the norepinephrine with vasoconstriction, inhibition of acetylcholine, and insulin release.
• β1 generates tachycardia, increased lipolysis, and increased myocardial contractility.
• β2 generates vasodilation.

Adrenergic Drugs: Centrally Acting alpha2 agonists

• Clonidine (Catapres) is a prototype.
• Other Medications: methyldopa (Aldomet)
• It stimulates alpha2-adrenergic receptors in the brain.
• It decreases sympathetic outflow from the CNS.
• It decreases norepinephrine production.
• It stimulates alpha2-adrenergic receptors.
• This reduces kidney renin activity.
• The result leads in decreased blood pressure.
• For opioid- or nicotine-dependent persons, it has indications for treating hypertension and withdrawal symptoms.
• Can be used for treating pregnancy-related hypertension and methylopa.

Nursing Administration

• Medications are usually administered twice daily.
• Should instruct patients to take larger dose at bedtime.
• Transdermal patches are applied every seven days.

Alpha Agonist Effects

• Caution patients with stroke, recent MI, major depressive, and renal failure.
• Monitor for drowsiness, sedation, dry mouth, and rebound hypertension.

Alpha1 Blocker

• Doxazosin mesylate (Cardura).
• Terazosin (Hytrin).
• Action Mechanism: Block alpha1-adrenergic, causing both venous/arterial dilation, less resistance, and results in decreased blood pressure
• Indications: treat hypertension, BPH to decrease resistance.
• Contraindications: Hypotension, angina, renal insufficiency.
• Teach safe measures, take first dose at night.

Alpha Blockers Adverse Effects

• The side effects include palpitations, orthostatic hypotension, chest pain, tachycardia, edema, and dysrhythmias.
• CNS may experience dizziness, headache, drowsiness, anxiety, depression, vertigo, weakness, numbness, and fatigue.
• Abdominal pain, diarrhea, constipation, nausea, and vomiting for gastrointestinal issues.
• Incontinence, tinnitus, or rhinitis occurs.

Adrenergic Drugs Beta-Blockers.

• It blocks the beta-receptors in the SNS.
• It competes with epinephrine and norepinephrine.
• They can be selective or nonselective.
• Both beta1 and beta2 receptors are blocked with nonselective beta-blockers.

Beta receptors.

• Beta1 receptors are primarily located on the heart.

• Beta-blockers are selective used on these receptors named cardioselective beta-blockers.

• Beta2 receptors are primarily located on bronchio smooth muscle and blood vessels.

• Mechanism of Beta blocker action: lowers heart rate through beta1-blockade. Reduced secretion of Renin. Over long-term reduces peripheral vascular resistance for decreased blood pressure.

Beta Blocker Types.

• Selective (Beta 1): reduce SNS stimulation, decrease heart rate, prolonged SA node recovery, slow conduction through the AV node causes reduction of oxygen demand and decreases myocardial contractility.
• Non-selective (Beta 1 & 2): the heart is the same as cardio-selective beta-blockers also constricts bronchioles to narrow airways, possible vasoconstriction of smooth muscle vessels, reduces heart rate.

Beta Blockers Indications

• Decreases for myocardial for angina.
• Cardioprotective stimulation from catecholamines and to prevent post MI arrest.
• For use with dysrhythmias to prevent migraine.
• Antihypertensive aids in heart failure and glaucoma with topical use.
• Propranolol (Inderal, carvedilol (Coreg, labetalol (Normodyne), metoprolol (Lopressor), atenolol (Tenormin), esmolol (Brevibloc).

Impotence Beta-Blocker

• Beta Blocker: Monitor for thrombocytopenia, for slowing heart rate, heart failure and insufficiency. To decrease lethargy effects, hallucinations, and depression with dry mouth and stomach cramps. Impotence, alopecia, and bronchospasm. Rebound symptoms can be chest pain, or hypertension if not discontinued properly.

Beta Blockers

• Inform patients of decreased tolerance with exercise. Inform if weight gain is more than 2-5 pounds for concerns on potential symptoms like syncope, fatigue, edema and shortness of breath.

Adrenergic Medication Adverse Effects

• High for orthostatic hypotension and cause of dry mouth, constipation, drowsiness can effect the CNS system for side effects allergic related problems such as with rashes.

Contraindications

• Monitor allergies, COPD conditions with alpha and beta blockers. Monitor for potential causes of heart failure, heart block, hypotension or Bronchoconstriction. Avoid OTC medications, with consideration drug interactions, antacids, antimuscarinics, cardiovascular drugs oral hypoglycemic or use of sympathetic medications.
• Teach patients to monitor symptoms, avoid the use of alcohol to not effect levels for palpations or medication changes.
• Take to assist in proper blood pressure and heart rate.

ACE (Angiotensin) inhibitors

• Large group for first time hypertension and heart disease used with thiazide or calcium channel blockers to block angiotensin-converting enzyme to produce angiotensin to vasodilation and decrease blood pressure (captopril and enalapril). Renin can extend life and lower ventricular.
• Monitor for blood and kidney protective function. To keep blood level regulated with potassium and non productive cough. Rare instances show a higher risk of fatal Angioedema.
• May use or combine oral with hydrochlorothiazide medication but report any rash or coughing symptoms to a medical provider.

ARBs (Angiotensin) II receptor blockers

• New alternative to ACE in hypertension treatment block for any vascular or stroke related conditions. Safe for kidneys but may cause respiratory infections, headache or for those who have a difficulty to treat. May increase with other medication with food on normal kidney function (ex. Cozaar, Hyzaar).

Calcium Channel Blockers (CCBs)

• For treatment of smooth contraction for relaxation related to cardiovascular conditions. Can relieve the constriction on smooth muscles with hypertension and migraines. Palpitations can occur may be administered but slow the dose to avoid any chest pain and administer extended release tablets.

Direct Renin Inhibitors

• Aliskiren is use to assist of production to Binds, decrease for angiotension II, or with high meals that may lead for allergic or diarrheal reactions needs to prevent in the 2-3 term on kidney related symptoms.

Use of Vasodilators

• Treatment of hypertension, hydralazine and other aids that will cause fluids and edema problems to avoid hypotension and any cerebral function.

Toxicity Vasodilators-

• Monitor of position symptom control with IV fluids to increase BP when supportive to treat

Conditions of SDOH

• Low educational environments can be influenced by poor areas where in monroe 36% may have low affordable care by $5-$23 with certain medications.

Nursing care

• Monitor regular blood, check for heart conditions, follow the medication, avoid doubling up for any missed treatments. May influence to monitor the use, smoking to not effect and increase levels. When swelling and if serious report to a doctor quickly. Over counter options and potential problems will have with approval .

• Patients should change position slowly, and avoid any light head effect to be cautious of light head injury and physical symptoms with lifestyle changes or exercises with diabetes to increase BP for the goal to not over due those conditions. To prevent to cardiovascular responses and to get frequent checks to avoid Beta Blockers/ CCB in certain color to not hinder effects.