Acute Coronary Syndrome (ACS)

Acute Coronary Syndrome (ACS)

• Umbrella term for myocardial ischemia caused by unstable angina, NSTEMI, or STEMI.

Unstable Angina

• Not associated with exercise or relieved by rest.
• May show ECG changes but not elevated cardiac enzymes.

NSTEMI

• Partial occlusion of a major coronary vessel.
• Complete occlusion of a minor coronary vessel with reversible damage to heart.

STEMI

• Complete occlusion of a major coronary vessel resulting in irreversible full thickness heart muscle damage.

Symptoms/Clinical Manifestations

• Jaw/tooth pain, shoulder blade pain, upper back pain, or pain in the left shoulder and arm.
• Shortness of breath, nausea, vomiting, sweating, and generalized fatigue are signs of ACS.
• Stable angina occurs with activity and is relieved by rest, whereas unstable angina occurs at rest.

Diagnosing

• ECG is the gold standard (ST depression indicates ischemia in NSTEMI, ST elevation indicates infarction in STEMI).
• Check troponin and CK/CK-MB levels to determine myocardial injury.
• CK-MB is a marker for tissue injury after being elevated for 3-36 hours after damage.
• Troponin levels will be elevated 4 hours-10 days after damage.

Risk Factors

• Modifiable: smoking, high LDLs, T2DM, increased catecholamines, obesity, inactivity, hypertension, atherosclerosis.
• Non-modifiable: male gender, postmenopausal women, family history of heart disease.

Actions

• Giving oxygen and inserting two large-bore IVs are important initial actions.
• Continuous ECG and medication administration is necessarty.

Invasive Treatment

• Percutaneous Coronary Intervention (PCI) is preferred for opening blocked vessels (within 90 mins).
• Fibrinolytics are given if PCI is not available and not contraindicated (within 30 minutes).
• CABG can be done if needed.

GOAL of treatment

• Maximize oxygenation and control pain through coronary artery dilation and prevention of clots while limiting myocardial workload.

Medication

• MONA: Oxygen, nitroglycerin, aspirin, and morphine.
• Beta blockers can reduce SNS response, but not in RCA MI.
• Heparin infusions can be started to reduce risk of clots.

Heart Failure

• Characterized by myocardial cell dysfunction, resulting in the inability of the heart to meet the body's demands.
• HFrEF (Systolic): EF < 45%, therapy is usually started
• HFpEF (Diastolic): EF >45% (normal EF is 55-70%)

Compensatory Mechanisms

• Activated in response to decreased stroke volume and cardiac output.
• Hypertrophy/stiffening of ventricle wall.
• HR, myocardial contraction, and vasoconstriction.
• RAAS activation contributes.

General HF symptoms

• Fatigue, weight gain, faster heart rates, hypo- or hypertension, murmurs from valve dysfunction.

Right-Sided HF

• JVD, dependent edema, hepatomegaly, ascites, and elevated CVP.

Left-Sided HF

• SOB, dyspnea, orthopnea, crackles on auscultation, pale color, weak pulses, and cool temperature in extremities.

Risk Factors

• CAD, HTN, hyperlipidemia, diabetes mellitus, metabolic syndrome, obesity, smoking, and high sodium dietary intake.

Monitoring

• Arrhythmias, skin color/temperature/CRT (due to decreased perfusion)
• Evaluate renal perfusion, fluid retention, and daily weight.
• VS: HTN (increased afterload), HOTN (acute HF), elevated HR (decreased CO), and elevated RR (decreased 02).
• Monitor heart and breath sounds, and look for pulmonary edema.
• Evaluate labs: Increased Cr/BUN, hepatic enzymes, and hypokalemia.

Goals of Therapy

• HFpEF: underlying cause treatment, BP control, diuretics for fluid overload, and symptom management.
• HFrEF: risk factor reduction and the manipulation of components of CO.
• Control of compensatory mechanisms (RAAS).

Diagnosis

• Largely dependent on history and physical exam, and other tests.
• Chest X-ray, Echo and ECGs can be used to diagnose.

Medical Interventions

• Predominately for HFrEF patients.
• Beta blockers help control.

Labs Tests

• Potassium levels are due to diuretic therapy.
• High BUN & Creatinine levels due to impaired renal perfusion & decreased CO.
• Low Hgb & Hct levels due to decreased renal perfusion (EPO).
• High BNP and NT-proBNP indicates overstretching of ventricles.

Invasive Intervention

• Automatic internal cardiac defibrillator (ICD) and continuous IV inotropic therapy can assist.
• Valve and Heart Replacement may assist.

ECG Interpretation

Rate

• Rate calculation: Count QRS complexes in a 6 second strip and multiply by 10 OR divide the number of small boxes between two R waves into 1500.
• Is it fast, slow, or within normal range?

Regular Rhythm

• Rhythm calculation: Count small boxes between wave to wave.
• Is it regular or irregular?
• Stay with patient until the arrhythmia has been corrected.

Arrhythmia general nursing interventions

• Obtain 12 lead ECG, ensure IV access available, and be prepared for cardioversion.
• Place defibrillator pads on patient and anticipate administering anti-anxiety medication.

Assess patient

• Assses skin color and temperature for changes
• Assess palpable pulses and LOC every 5 minutes.

Sinus Bradycardia

• A regular rhythm with same characteristics as NSR except HR is less than 60 bpm.
• Can be caused by hypoxia, hypothermia, sleep, or normal rate for athletes.
• If symptomatic: treatment needed

Symptoms

• Hypotension, dizziness, lightheadedness
• Possible fainting, SOB, Sweating, or Anxiety

Sinus Tachycardia

• Regular rhythm that has same characteristics as NSR except HR is greater than 100 bpm. •Can be caused by fever, anemia, hypovolemia, HOTN, PE, or MI.

Symptoms

• Hypotension, dizziness, lightheadedness
• Possible fainting, SOB, Sweating, anxiety, or palpitations

Treatments

• Use oxygen or atropine, and consider pacing.
• Fix the causes: Remove what caused the ischemia like hypoxia or toxicities

Atrial Dysrhythmias

• Caused by pacemaker cells firing from somewhere else other than the SA node, but still in the Atria.

Types:

• Atrail fibrilation (A- fib) and Atrail flutter ( A-flutter)

Atrial Fibrillation

• Most commonly seen. -Can last from 10 seconds to more than 12 months, requires medicine treatments and cardioversion.
• Cause: cardiomyopathy, pericarditis, hyperthyroidism, HTN, valvular disease, obesity, diabetes, CKD, or cardiac surgeries.

Atrail Flutter ( A-flutter)

• Cause: acute MI, severe mitral valve disease, thyrotoxicosis, COPD, or cardiac surgeries.
• No defined P wave present

Supraventricular Tachycardia. (SVT)

• A rapid heart rhythm that originates from electrical signals above ventricles.
• Often called Paroxysmal SVT (PSVT): intermittent SVT, coming on/stopping quickly.

Ventricular Dysrhythmia

• Originate from somewhere in the ventricles, no P wave, QRS complex is wide.
• Assess patient for irregular blood pressue, hypoxia, and palpitations

Ventricular Tachycardia

• There are over 3 PVC's (Premature ventricular contractions) that are in a row.
• Without a pulse! Three or more PVCs: life threatening rhythm.

Ventricular Fibrilation

• Lethal rhythm, needs immediate intervention, use antiarrhythmic or cardiac conversion