SECTION II – CARDIAC SYSTEM
💉 Cardiac Labs Quick Chart
Lab Normal Range Abnormal Meaning / Clinical Significance
Troponin I < 0.03 ng/mL ↑ > 0.04 = Cardiac muscle injury (MI)
Troponin T < 0.01 ng/mL ↑ > 0.02 = MI indicator
CK-MB 0–3 ng/mL ↑ within 6 hr = confirms MI
BNP < 100 pg/mL ↑ = Heart Failure
Myoglobin < 90 mcg/L ↑ = Early MI marker (not specific)
LDL < 100 mg/dL ↑ = Atherosclerosis risk
HDL > 40 mg/dL ↓ = CAD risk
Triglycerides < 150 mg/dL ↑ = CAD risk
K⁺3.5–5.0 mEq/L ↑ or ↓ = dysrhythmias
Na⁺135–145 mEq/L ↓ = fluid overload in HF
❤️ Acute Coronary Syndrome / Myocardial Infarction (MI)
Unstable Angina
Chest pain at rest; not relieved with nitroglycerin
↑ frequency and severity; > 15 min duration
ST changes on EKG with negative troponin and CK-MB
Assess PQRST of pain (Provoking, Quality, Radiation, Severity, Timing)
ST-Elevation MI (STEMI)
100% coronary occlusion = ischemia → injury → infarction
Inverted T wave = Ischemia
ST elevation = Injury
Pathologic Q wave = Infarction
S/S of MI
Crushing chest pain radiating to jaw/back/shoulder/abdomen
N/V, diaphoresis, dyspnea, fatigue, dizziness
S3 sound = early sign of HF
↑ WBC after MI (due to tissue necrosis)
Priority Interventions
, 1. 12-lead ECG within 10 minutes of arrival (“door-to-ECG”)
2. MONA: Morphine → O →₂ Nitroglycerin → Aspirin (chewable 325 mg)
3. Start IV access, continuous telemetry, vitals q 5 min
4. Prepare for thrombolytics or PCI if indicated
Thrombolytic Therapy (Alteplase, Reteplase, Tenecteplase)
Give only if STEMI and onset < 6 hrs
Contraindicated: recent surgery, head trauma, stroke, pregnancy, PUD, anticoagulant
use
⚠️ NCLEX ALERT
Administer O first,
₂ then obtain ECG before notifying provider.
Hold Nitroglycerin if SBP < 90 mm Hg or if using phosphodiesterase inhibitors (Viagra, Cialis).
❤️ Percutaneous Coronary Intervention (PCI)
Pre-Procedure
Obtain consent, labs (BUN/Cr, coagulation profile), NPO status
Assess for iodine/contrast allergy
Empty bladder before transfer
Post-Procedure Care
Keep affected leg straight, HOB < 30°
Vitals q 15 × 4, q 30 × 4, then hourly × 24 hrs
Assess distal pulses and puncture site for bleeding/hematoma
Maintain IV fluids to flush contrast dye
Report output < 30 mL/hr or cool extremity
⚠️ NCLEX ALERT
If chest tube/puncture site drainage > 150 mL/hr or sudden neurologic changes → notify
provider immediately.
❤️ Coronary Artery Bypass Graft (CABG)
Post-Op Care
, Chest tubes (2 pleural + 1 mediastinal) → report > 150 mL/hr drainage
Temporary pacing wires and sternal precautions (no lifting > 10 lb)
Monitor hemodynamics, electrolytes, infection at sternal site
Strict sterile technique for dressings
Complications
Dysrhythmias (PVCs, VT, VF, Asystole)
Hypotension or Hypertension
Bleeding, Electrolyte imbalances, Tamponade
❤️ Cardiac Tamponade
Pathophysiology:
Fluid accumulates in the pericardial sac → compresses the heart → ↓ cardiac output →
medical emergency!
S/S:
Jugular vein distention (JVD)
Muffled or distant heart sounds (“underwater” sound)
Hypotension
Tachycardia
Pulsus paradoxus (↓ SBP > 10 mmHg on inspiration)
Intervention:
Pericardiocentesis to remove fluid immediately
Monitor for return of cardiac output and normal sounds
⚠️ NCLEX ALERT
Classic triad of cardiac tamponade: JVD + muffled heart sounds + hypotension.
❤️ Heart Failure (Left vs Right)
Type S/S Nursing Interventions
Left-Sided Pulmonary congestion, dyspnea, orthopnea, Oxygen, Fowler’s position,
HF crackles, pink frothy sputum diuretics, monitor O ₂ sats
Right-Sided Systemic congestion, edema, ascites, JVD, Elevate legs, diuretics, daily
HF weight gain weights, fluid restriction
💉 Cardiac Labs Quick Chart
Lab Normal Range Abnormal Meaning / Clinical Significance
Troponin I < 0.03 ng/mL ↑ > 0.04 = Cardiac muscle injury (MI)
Troponin T < 0.01 ng/mL ↑ > 0.02 = MI indicator
CK-MB 0–3 ng/mL ↑ within 6 hr = confirms MI
BNP < 100 pg/mL ↑ = Heart Failure
Myoglobin < 90 mcg/L ↑ = Early MI marker (not specific)
LDL < 100 mg/dL ↑ = Atherosclerosis risk
HDL > 40 mg/dL ↓ = CAD risk
Triglycerides < 150 mg/dL ↑ = CAD risk
K⁺3.5–5.0 mEq/L ↑ or ↓ = dysrhythmias
Na⁺135–145 mEq/L ↓ = fluid overload in HF
❤️ Acute Coronary Syndrome / Myocardial Infarction (MI)
Unstable Angina
Chest pain at rest; not relieved with nitroglycerin
↑ frequency and severity; > 15 min duration
ST changes on EKG with negative troponin and CK-MB
Assess PQRST of pain (Provoking, Quality, Radiation, Severity, Timing)
ST-Elevation MI (STEMI)
100% coronary occlusion = ischemia → injury → infarction
Inverted T wave = Ischemia
ST elevation = Injury
Pathologic Q wave = Infarction
S/S of MI
Crushing chest pain radiating to jaw/back/shoulder/abdomen
N/V, diaphoresis, dyspnea, fatigue, dizziness
S3 sound = early sign of HF
↑ WBC after MI (due to tissue necrosis)
Priority Interventions
, 1. 12-lead ECG within 10 minutes of arrival (“door-to-ECG”)
2. MONA: Morphine → O →₂ Nitroglycerin → Aspirin (chewable 325 mg)
3. Start IV access, continuous telemetry, vitals q 5 min
4. Prepare for thrombolytics or PCI if indicated
Thrombolytic Therapy (Alteplase, Reteplase, Tenecteplase)
Give only if STEMI and onset < 6 hrs
Contraindicated: recent surgery, head trauma, stroke, pregnancy, PUD, anticoagulant
use
⚠️ NCLEX ALERT
Administer O first,
₂ then obtain ECG before notifying provider.
Hold Nitroglycerin if SBP < 90 mm Hg or if using phosphodiesterase inhibitors (Viagra, Cialis).
❤️ Percutaneous Coronary Intervention (PCI)
Pre-Procedure
Obtain consent, labs (BUN/Cr, coagulation profile), NPO status
Assess for iodine/contrast allergy
Empty bladder before transfer
Post-Procedure Care
Keep affected leg straight, HOB < 30°
Vitals q 15 × 4, q 30 × 4, then hourly × 24 hrs
Assess distal pulses and puncture site for bleeding/hematoma
Maintain IV fluids to flush contrast dye
Report output < 30 mL/hr or cool extremity
⚠️ NCLEX ALERT
If chest tube/puncture site drainage > 150 mL/hr or sudden neurologic changes → notify
provider immediately.
❤️ Coronary Artery Bypass Graft (CABG)
Post-Op Care
, Chest tubes (2 pleural + 1 mediastinal) → report > 150 mL/hr drainage
Temporary pacing wires and sternal precautions (no lifting > 10 lb)
Monitor hemodynamics, electrolytes, infection at sternal site
Strict sterile technique for dressings
Complications
Dysrhythmias (PVCs, VT, VF, Asystole)
Hypotension or Hypertension
Bleeding, Electrolyte imbalances, Tamponade
❤️ Cardiac Tamponade
Pathophysiology:
Fluid accumulates in the pericardial sac → compresses the heart → ↓ cardiac output →
medical emergency!
S/S:
Jugular vein distention (JVD)
Muffled or distant heart sounds (“underwater” sound)
Hypotension
Tachycardia
Pulsus paradoxus (↓ SBP > 10 mmHg on inspiration)
Intervention:
Pericardiocentesis to remove fluid immediately
Monitor for return of cardiac output and normal sounds
⚠️ NCLEX ALERT
Classic triad of cardiac tamponade: JVD + muffled heart sounds + hypotension.
❤️ Heart Failure (Left vs Right)
Type S/S Nursing Interventions
Left-Sided Pulmonary congestion, dyspnea, orthopnea, Oxygen, Fowler’s position,
HF crackles, pink frothy sputum diuretics, monitor O ₂ sats
Right-Sided Systemic congestion, edema, ascites, JVD, Elevate legs, diuretics, daily
HF weight gain weights, fluid restriction
