Chapter 6: Cardiovascular Nursing — Heart Failure, MI, and Cardiac Monitoring

Cardiovascular disease is the leading cause of death worldwide. Nurses in every setting — from ICU to home health — encounter patients with heart failure, coronary artery disease, and arrhythmias. Rapid, accurate assessment and targeted interventions are life-saving.

Heart Failure: Left vs. Right

Heart failure (HF) occurs when the heart cannot pump adequate blood to meet the body’s metabolic needs. Understanding which ventricle is failing guides assessment and interventions.

Feature	Left-Sided HF	Right-Sided HF
Mechanism	LV fails → blood backs into pulmonary circulation	RV fails → blood backs into systemic venous circulation
Hallmark symptom	Dyspnea, orthopnea, PND	Peripheral edema, JVD, ascites
Breath sounds	Crackles (pulmonary edema)	Clear (unless biventricular)
Weight	Daily weight gain (>2 lbs/day = notify MD)	Same
Key assessment	SpO₂, respiratory rate	Daily weight, peripheral edema, JVD

NYHA Classification: Class I (no symptoms with activity) → Class IV (symptoms at rest).

Myocardial Infarction (MI) Nursing Care

MI occurs when coronary artery occlusion causes myocardial ischemia leading to cell death. Nursing priorities follow MONA (now evidence-updated):

• Morphine — use cautiously (associated with worse outcomes in NSTEMI)
• Oxygen — only if SpO₂ < 90%
• Nitroglycerin — for chest pain relief (hold if SBP < 90, recent PDE-5 inhibitor use)
• Aspirin — 325 mg chewable immediately unless contraindicated

Key nursing actions: 12-lead ECG within 10 minutes of symptom onset, IV access, continuous cardiac monitoring, labs (troponin, CK-MB, BNP), prepare for PCI or thrombolytics.

STEMI vs. NSTEMI: STEMI shows ST elevation; requires emergent PCI (door-to-balloon ≤90 minutes). NSTEMI has elevated troponin without ST elevation.

ECG Basics

Component	Normal Value	Clinical Significance
P wave	< 0.12 sec	Atrial depolarization
PR interval	0.12–0.20 sec	AV conduction time
QRS complex	< 0.12 sec	Ventricular depolarization
QT interval	< 0.44 sec (corrected)	Ventricular repolarization; prolonged QTc = TdP risk
ST segment	Isoelectric	ST elevation = STEMI; ST depression = ischemia

Cardiac Medications

Digoxin (cardiac glycoside): increases contractility, slows AV conduction. Check apical pulse for 1 full minute before administering — hold if < 60 bpm in adults. Signs of toxicity: bradycardia, N/V, visual disturbances (yellow-green halos), arrhythmias. Therapeutic level: 0.5–2.0 ng/mL. Hypokalemia increases toxicity risk.

Beta-blockers (metoprolol, carvedilol): reduce heart rate and myocardial oxygen demand. Hold if HR < 50 or SBP < 90. Do not abruptly discontinue.

ACE Inhibitors/ARBs: reduce afterload and prevent cardiac remodeling in HF. Monitor for hypotension, hyperkalemia, renal function. ACE inhibitors cause dry cough (switch to ARB).

Key Checklist

• Compare left-sided and right-sided heart failure: mechanisms, hallmark symptoms, and priority nursing assessments
• Describe the nursing actions to take within the first 10 minutes of a suspected MI (MONA + diagnostics)
• State the apical pulse threshold for holding digoxin and list three signs of digoxin toxicity