Cardiac Disorders

Heart Failure

Aspect	Left-Sided HF	Right-Sided HF
Pathophysiology	Left ventricle fails to pump effectively → blood backs up into lungs	Right ventricle fails → blood backs up into systemic circulation (usually caused by left-sided HF)
Symptoms	Dyspnea, orthopnea, PND, crackles/rales, pink frothy sputum, tachycardia, S3 heart sound, fatigue	JVD, hepatomegaly, splenomegaly, peripheral edema (dependent), weight gain, ascites, anorexia
Diagnostics	BNP > 100 pg/mL, CXR (pulmonary congestion, cardiomegaly), echocardiogram (reduced EF)	JVD assessment, hepatojugular reflux, echocardiogram

HF Management

• Medications: ACE inhibitors (-prils), ARBs (-sartans), beta-blockers (carvedilol, metoprolol), diuretics (furosemide), digoxin, aldosterone antagonists (spironolactone)
• Nursing: Daily weights (same time, same scale), low-sodium diet (< 2g/day), fluid restriction (1.5–2 L/day), I&O, elevate HOB, monitor K+ with diuretics
• Teach: Report weight gain > 2 lbs/day or 5 lbs/week, avoid NSAIDs, no alcohol

Myocardial Infarction

Aspect	STEMI	NSTEMI
ECG	ST elevation in contiguous leads	ST depression, T-wave inversion, or no acute changes
Troponin	Elevated	Elevated
Treatment	Emergent PCI (within 90 min) or fibrinolytics (within 30 min if no PCI available)	Medical management, possible cardiac catheterization

MI Management — MONA (Modified)

• Morphine (if pain unrelieved by nitro; use cautiously)
• Oxygen (only if SpO2 < 94%)
• Nitroglycerin (SL q5min x3; hold if SBP < 90; do NOT give with PDE5 inhibitors)
• Aspirin (162–325 mg, chewed immediately)
• Also: Heparin, beta-blockers, ACE inhibitors, statins

Common Arrhythmias

Rhythm	Rate	Key Features	Treatment
Sinus Bradycardia	< 60	Regular, normal P waves	Atropine (first-line), pacing if symptomatic
Sinus Tachycardia	> 100	Regular, normal P waves	Treat underlying cause (pain, fever, hypovolemia)
Atrial Fibrillation	Irregular, 350–600 (atrial)	No discernible P waves, irregularly irregular	Rate control (diltiazem, beta-blocker), anticoagulation, cardioversion
Atrial Flutter	Atrial 250–350	Sawtooth P waves	Similar to A-fib; cardioversion often effective
V-Tach (with pulse)	150–250	Wide QRS, no P waves	Amiodarone, synchronized cardioversion
V-Tach (pulseless)	—	Wide QRS, no pulse	CPR + defibrillation + epinephrine + amiodarone
V-Fib	—	Chaotic, no organized rhythm	CPR + defibrillation (priority #1) + epi + amiodarone
Asystole	0	Flat line (confirm in 2 leads)	CPR + epinephrine (do NOT defibrillate)
3rd Degree Heart Block	Varies	P waves and QRS completely independent	Transcutaneous pacing, atropine may help, permanent pacemaker

ECG Basics

Component	Represents	Normal Duration
P wave	Atrial depolarization	0.06 – 0.12 sec
PR interval	AV node conduction time	0.12 – 0.20 sec (prolonged = heart block)
QRS complex	Ventricular depolarization	0.06 – 0.12 sec (wide > 0.12 = bundle branch block or ventricular origin)
ST segment	Early ventricular repolarization	Isoelectric (elevation = MI, depression = ischemia)
T wave	Ventricular repolarization	Upright in most leads (peaked = hyperkalemia, inverted = ischemia)
QT interval	Total ventricular activity	0.36 – 0.44 sec (prolonged = torsades risk)

Key Cardiac Medications

• ACE Inhibitors (-pril): Monitor K+, BUN/Cr; hold for hyperkalemia; dry cough is common side effect; angioedema is rare but serious
• Beta-Blockers (-olol): Hold for HR < 60, SBP < 90; do not stop abruptly (rebound tachycardia); mask hypoglycemia signs in diabetics
• Calcium Channel Blockers (diltiazem, verapamil, amlodipine): Monitor HR and BP; constipation common with verapamil
• Nitroglycerin: Headache is expected; store in dark glass; SL q5min x3 then call 911; monitor for hypotension
• Amiodarone: Monitor thyroid, liver, lungs (pulmonary toxicity); photosensitivity; multiple drug interactions