Cardiology and Hypertension Notes

Angiography

  • Angiography involves the use of dye.
  • Before the exam, report these findings to the physician:
    • Allergy to iodine.
    • Serum creatinine level of 2.1 (indicative of renal issues).
    • Allergy to shrimp.
  • Atrial fibrillation is not a contraindication for cardiac angiography.

Diminished Cardiac Output Signs

  • Signs to assess for include:
    • Bradycardia.
    • Change in level of consciousness (LOC).
    • Oliguria (poor perfusion to the kidneys).
    • Hypotension.
    • Weak peripheral pulses (bounding pulses are not indicative of diminished cardiac output).

Sinus Rhythms

  • Sinus rhythm originates from the SA node.
  • All sinus rhythms have P waves.
  • Normal conduction pathway:
    • SA node → internodal pathway → AV node → Bundle of His → bundle branches → Purkinje fibers.

Normal Sinus Rhythm

  • SA node discharges and follows the normal conduction pathway without disturbances.
  • Considered normal.
  • Five steps to assess:
    • Rate: 60 to 100 bpm.
    • Rhythm: Regular.
      • A slight variation (half a box off for the last two R waves) is still considered regular.
    • P Waves: Present and with the same shape for every QRS complex.
    • PR Interval: 0.12 to 0.20 seconds.
      • Count from the beginning of the P wave to the beginning of the QRS complex.
      • Should be consistent.
    • QRS Complex: Less than 0.12 seconds.
      • Measure from the beginning of the QRS complex to the J point.
    • Interpretation: If all parameters are normal, it's a sinus rhythm or normal sinus rhythm.

Heart Rate Calculation

  • Approximation: Count the number of R waves in a 6-second strip and multiply by 10.
  • Exact heart rate: Divide 1500 by the number of small boxes between two R waves.
    • $$Heart Rate = "".

Sinus Bradycardia

  • SA node discharges slower than usual but still follows the normal conduction pathway.
  • Everything is normal except the heart rate, which is less than 60 bpm.
  • If the strip is a six-second strip, count how many QRS complexes there are and multiply by 10. That's approximation but an exact way to do it is 1500 divided by the amount of boxes between the QRS complex.
  • Assessment:
    • Rhythm: Regular.
    • P Waves: Present and the same for every QRS.
    • PR Interval: 0.12-0.20 seconds (normal).
    • QRS Complex: Less than 0.12 seconds (normal).

Management of Sinus Bradycardia

  • Assess if the patient is symptomatic or asymptomatic.
  • Possible causes:
    • Vagal stimulation.
      • Educate the elderly about straining during bowel movements.
    • Beta-blockers.
    • Calcium channel blockers.
    • Narcotics.
    • Ischemia.
    • Athletes naturally have a lower heart rate.
  • Only treat if symptomatic.
  • Signs and symptoms of bradycardia (diminished cardiac output):
    • Shortness of breath (SOB).
    • Confusion/disorientation.
    • Dizziness.
    • Angina (due to slow pumping of blood to the heart muscle).

Interventions for Symptomatic Bradycardia

  • Vital support:
    • Oxygen if hypoxic.
    • Head of the bed down if hypotensive.
    • Positioning: Supine with feet elevated (avoid Trendelenburg position, which can impair respiration).
  • IV access for medication administration.
  • Medications:
    • Atropine: 1 mg every 3-5 minutes, maximum of 3 mg.
    • Isoproterenol: Sympathomimetic used for second-degree type II AV block and third-degree block when atropine is ineffective.
  • If medications are ineffective, consider temporary pacing (transcutaneous) or permanent pacing.

Sinus Tachycardia

  • SA node discharges more frequently or faster but follows the normal conduction pathway.
  • Rate: 101 to 150 bpm.
  • Everything is normal except the heart rate.
  • T wave and P wave may appear back-to-back but not a premature atrial contraction (PAC).
  • Causes:
    • Fever.
    • Anxiety.
    • Excitement.
    • Medications.
    • Pulmonary embolism (PE).
    • Pain (acute vs. chronic).

Management of Sinus Tachycardia

  • Vagal maneuvers: Only if the heart rate is more than 160 bpm.
    • Examples: Valsalva maneuver (bearing down as if constipated), blowing hard on a straw.
  • Medications:
    • Beta-blockers.
    • Calcium channel blockers (e.g., diltiazem).
  • Treat the underlying cause (e.g., pain medication for pain).
  • Pacemakers are not used for tachycardia.
    Synchronized cardioversion is not required for sinus tachycardia and therefore not necessary.

Sinus Arrhythmia

  • Everything is normal except the rhythm, which is irregular.
  • Heart rate is usually 60 to 100 bpm or depends on the underlying rhythm.
  • If irregular rhythm and slow heart rate, describe it as sinus arrhythmia with bradycardic rate (do not call it sinus bradycardia).

Management of Sinus Arrhythmia

  • If bradycardic rate and symptomatic, then treat.
  • Otherwise, if asymptomatic, no treatment is needed; continue monitoring.

Sinus Pause or Sinus Arrest

  • SA node fails to discharge and then resumes, or a lower pacemaker begins to discharge.
  • Pause time interval is not a multiple of the normal R-to-R interval.
  • Determine if it's a pause, arrest, or block.
  • Underlying rhythm is the rhythm occurring before the abnormality.

Differentiation Between Sinus Arrest/Pause and Sinus Block

  • Sinus Arrest/Pause: The next complex does not occur in the same rhythm (either comes before or after it should).
  • Sinus Block: The next complex resumes in the same rhythm.
  • With either a block or arrest, it will drop the whole complex (PQRST).
  • The number of dropped beats does not matter for diagnosis.

Etiology and Management of Sinus Arrest/Pause and Sinus Block

  • Causes: Vagal response, heart disease, or medications.
  • Rhythm becomes irregular where the drop beat occurs.
  • Signs: Decreased cardiac output.
  • Patients may present with chest pain or palpitations.

Hypertension

  • Hypertension is defined as systolic blood pressure of 130 or higher, or diastolic of 80 or higher.
  • Based on an average of two or more accurate blood pressure measurements taken 1-4 weeks apart by a healthcare provider.
  • If the systolic is over 180, then this is considered a hypertensive crisis.

Classification of Blood Pressure for Adults

  • Normal: Less than 120/80 mmHg.
  • Elevated Blood Pressure (Prehypertension): 120-129/<80 mmHg.
  • Stage 1 Hypertension: 130-139/80-89 mmHg.
  • Stage 2 Hypertension: ≥140/≥90 mmHg.

Types of Hypertension

  • Primary (Essential/Idiopathic): 90-95% of cases, cause unknown.
  • Secondary: From an underlying illness (e.g., renal disease, sleep apnea).
    • Sleep apnea contributes to hypertension due to decreased oxygenation during sleep, leading to stress on the body.
  • High prevalence in African Americans (genetic and dietary factors).

Consequences of Hypertension

  • Silent killer because it can damage major organs before symptoms appear.
  • Can lead to:
    • Stroke.
    • Blindness (diabetic retinopathy).
    • Heart attack/cardiac arrest.
    • Heart failure.
    • Kidney failure/renal damage.

Manifestations of Hypertension

  • Headache.
  • Chest pain.
  • Blurry vision.
  • Palpitations.
  • Neck pain.

Pathophysiology of Hypertension

  • Increased cardiac output and/or peripheral vascular resistance.
  • Autonomic nervous system activation (fight or flight response).
  • Renin-Angiotensin-Aldosterone System (RAAS) dysfunction.
    • RAAS is activated by low blood pressure or fluid volume.
    • Renin converts to angiotensin I, then to angiotensin II (a potent vasoconstrictor), increasing blood pressure.
  • Resistance to insulin action and activation of the immune system (related to cortisol levels).

Monitoring Blood Pressure

  • Use the correct cuff size.
  • Patient should be seated, feet on the floor, arm resting at heart level.
  • If manually measuring, palpate for the brachial artery and inflate 30 mmHg above the known systolic pressure, then release slowly.

Hypertension - Types

  • Masked Hypertension: Normal in-office blood pressure readings but elevated out-of-office readings.
  • White Coat Syndrome/Hypertension: Elevated blood pressure in a clinical setting due to anxiety.
  • Orthostatic:
    * Heart rate increases 20, which could cause that, too.

Risk Factors for Hypertension

  • Smoking.
  • Obesity.
  • Inactivity.
  • Hyperlipidemia (high cholesterol; LDL should be low, HDL high).
  • Family history.

Assessment and Diagnostics

  • Retinal exam (annually).
  • Urinalysis (to check for protein, indicating kidney damage).
  • Blood chemistry (lipids).
  • EKG (for dysrhythmias).
  • Uric acid level (to establish a baseline since diuretic therapy can elevate it).

Management of Hypertension

  • Maintain a healthy blood pressure.
  • Lifestyle modifications:

DASH Diet

  • Dietary Approaches to Stop Hypertension (DASH diet).
  • Example: 4-5 servings of vegetables and fruits, fat-free/low-fat dairy, etc.
  • Regular physical activity:
    • 30-45 minutes of walking most days of the week.
  • Reduce alcohol consumption.
  • Stop smoking.

Pharmacologic Therapy

  • If lifestyle modifications are insufficient, medications are added.
  • Medications decrease peripheral resistance, blood volume, and myocardial contractility.
  • Examples:
    • Diuretics.
    • Beta-blockers.
    • ACE inhibitors.

JNC Guidelines for Medication Selection

  • Thiazide diuretics are often the first-line treatment, especially for non-African Americans.
  • Start with a low dose and gradually increase, then add another medication if needed.
  • Loop diuretics (e.g., furosemide) are not the first choice but can be added if other medications are insufficient.

Considerations for Geriatric Patients

  • Polypharmacy is common; simplify the medication regimen if possible.
  • Involve family and caregivers in education.

Hypertensive Crisis

  • Blood pressure above 180/120 mmHg.
  • Two types:
    • Hypertensive Emergency: requires hospitalization and IV medications due to imminent or progressive target organ damage (like stroke).
      • Goal: Reduce blood pressure by no more than 25% in the first hour, except in ischemic stroke and aortic dissection.
    • Hypertensive Urgency: No evidence of immediate target organ damage, can be managed with oral medications and close monitoring.
      • Goal: Normalize blood pressure within 24-48 hours.

Medications for Hypertensive Crisis

  • Hypertensive Emergency: IV vasodilators (e.g., nitroprusside, enalapril, nitroglycerin).
  • Hypertensive Urgency: Oral agents (e.g., labetalol, clonidine, hydralazine).
    Intake and output, monitoring frequently is important when administering meds for hypertensive crisis. If the patients blood pressure goes down too fast because of medications like nitroprusside, volume replacement with normal saline can prevent large sudden drops in blood pressure. That's why you need to know if the patient is volume depleted and have a baseline for this patient when dealing with this. INO with that type of information can help with finding the right course of action. It also can help from a patient going into a hypertensive state which causes more damage to the patient. Remember if treating a patient suffering form hypertensive crisis you do not want the pressure too high or too low to avoid problems with the patients situation. . Also, a rule is hypertensive patients are okay being hypertensive so it will not be harmful but you do not want hypotension, which will cause more harm that good overall. That's why you need to have some type of happy medium for better outcomes for the patient's future.