1.4 Electrocaradiograms

Achievable NPTE-PTA

1. Cardiopulmonary system

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Electrocaradiograms

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How to read electrocardiograms

Definitions

P wave: Atrial depolarization/contraction
PR interval: Represents the time it takes for the electrical signal to move from the ventricles to SA node
QRS complex: Ventricular depolarization/contraction
T wave: Ventricular repolarization/relaxation

Important considerations for reading electrocardiograms

Is the rhythm regular and consistent?
Is the rate fast, slow, or normal?
Are P waves present and look the same?:
Is the PR interval normal and consistent?
Are the QRS complexes normal and immediately follow the P wave?
Is the T wave present and normal in appearance?
When viewing a multiple lead EKG strip view lead II or the line where the pattern can be defined clearly.
Inverted waves are a polarity reversal often from improper lead placement, It is important to focus on the pattern listed above 1-6.

Calculation of heart rate with EKG

Calculation of heart rate using an EKG should only be done when the rhythm is consistent and predictable, allowing for easy calculations.

Calculations as follows for a 6-second strip method:

Count the number of QRS complexes in 6 seconds and multiply by 10

Example:

7 QRS peaks noted in 6 seconds x 10 = 70 bpm (heart rate). This is in the normal range of 60-100.

Common EKGs

Sinus bradycardia (slow heart rate, below 60 beats per minute at rest)

PT implications:

Common to see this rhythm when working with those taking beta-blockers and in the elderly population
If present, ok to proceed with initiation of activity and continuance of activity,
- Will need to use the perceived exertion scale (RPE)to assess tolerance to activity
- Monitor for symptoms of dizziness, lightheadedness, and pallor

Sinus tachycardia (fast heart rate), > 100 beats per minute at rest)

PT implications:

Common to observe this rhythm during exercise
Pay attention if the individual develops a headache, dizziness, or lightheadedness with tachycardia
- If these symptoms present, the therapist will stop the activity and reassess all vitals

A-fibrillation (A-fib)

Irregular, tachycardic heart rhythm in which the atrium contracts erratically; the EKG presents with no P-wave and irregular rhythm due to a fast heart rate

PT implications

If not previously recognized, stop activity and notify

If identified previously:

Vital sign monitoring
- Continuous or frequent monitoring of heart rate, blood pressure, and oxygen saturation is essential.
- Pulse may be irregular, so use auscultation or ECG for accuracy rather than the radial pulse alone.
- Be aware that heart rate may be elevated or vary unpredictably.
Exercise prescription
- Begin with low to moderate intensity activities; avoid high-intensity or sudden exertion early in rehab.
- Use Rate of Perceived Exertion (RPE) rather than heart rate alone due to variability.
- Monitor for signs of exercise intolerance: dizziness, fatigue, palpitations, chest pain, or dyspnea.

A-flutter

Regular, tachycardiac contraction of atrium; constant p wave contraction leads sawtooth pattern of P wave

PT implications

If not previously recognized, stop activity and notify

If identified previously:

Vital sign monitoring
- A-flutter often presents with a regular but rapid atrial rate (240–400 bpm); ventricular response may be regular or irregular depending on AV block.
- Carefully monitor heart rate and rhythm, as patients may suddenly shift into more dangerous rhythms (e.g., atrial fibrillation or rapid ventricular response).
- Use ECG or telemetry when possible, especially in acute care settings.
Exercise intensity and progression
- Initiate with low to moderate intensity aerobic activity.
- Use RPE scales to guide intensity because HR may not accurately reflect exertion, especially if rate-controlled.
- Avoid abrupt changes in activity that could increase sympathetic tone and trigger rhythm instability.

Premature ventricular contraction (PVC)

Irregular heart rhythm in which the ventricles contract before the atrium, which causes a brief heart rate pause to allow for a reset to the normal contraction pattern.

PT implications

Singular PVC at rest and exercise: initiate or continue with activity, as this can be an anomaly
- Can be caused by stress, caffeine, or idiopathic
Bigeminy (2) stop and rest x 5 min resume ex only if resolved,
Three or more PVCs in a row at rest or with exercise: do not initiate activity and discontinue exercise, as this could lead to fatal heart rhythms
- Monitor for symptoms: heart fluttering, heart pounding, missed heartbeats

Ventricular tachycardia

Irregular, tachycardic contraction of only the ventricles (no atrial contraction means no flow of blood)

PT implications

Medical emergency and CPR initiated

Ventricular fibrillation

Irregular, tachycardic quivering of the ventricular (no true contraction of the ventricles, which means blood flow of the heart

PT implications

Medical emergency and CPR initiated

Lab values

Lab values can be found at the American Physical Therapy Association (APTA) interpretation guide.

Vital signs

Temperature: 97℉ - 99.6℉
- High value indicates fever
Resting heart rate: 60-100 beats per minute
- Below 60 indicates bradycardia
- Above 100 indicates tachycardia
Respiration: 12- 20 breaths per minute
- Below 12 indicates respiratory depression
- Above 20 indicates hyperventilation
Blood pressure: 120/80
- See Chapter 2.1
Oxygen saturation (O2 sats) 90%-100%
- Below 90% indicates possible need for supplemental oxygen

Hematological - Complete blood count

Hemoglobin: responsible for transporting oxygen via red blood cells
- Male: 14-18
- Female: 12-16
  - Below normal values indicate anemia, which increases the risk for blood transfusion
  - An above normal value indicates polycythemia, which increases the risk for clogging of capillaries

Definitions

Anemia: Due to low red cell blood count, the individual presents with fatigue, pallor, shortness of breath, weakness, and lightheadedness, especially during exertion
Polycythemia: Excessive red blood cells, which lead to increased volume and thickness of the blood; symptoms include headache, dizziness, nose bleeds, vision changes, and red skin

Hematocrit: ratio of red blood cells to total volume of blood
- Male: 42%-52%
- Female: 37%-47%
  - Below normal values indicate anemia, which increases the risk for blood transfusion or need for fluids *An above normal value indicates polycythemia, which increases the risk for clogging of capillaries
Platelets: clot-forming components of blood
- 150,000-400,000 mm³
  - Below 150,000 mm³indicates thrombocytopenia, which increases risk for hemorrhage, bleeding from gums, heavy menstrual bleeding, or blood in urine or stools
  - Above 400,000 mm³ indicates thrombocytosis which increases risk for DVT development
White blood count: important in immune response to infectious processes
- 5,000 - 10,000 mm³
  - Below 5,000 mm³ indicates leukopenia which increases the risk for recurrent infections
  - Above 10,000 mm³ indicates leukocytosis, which increases the risk for inflammation, immune system, or bone marrow disease
Red blood count: cells that carry oxygen from the lungs to the tissue and are produced within the bone marrow
- Male: 4.7-6.1
- Female: 4.2-5.4
  - Below normal values indicate anemia, which increases the risk for blood transfusion
  - An above normal value indicates polycythemia, which increases the risk for myocardial infarction and stroke
INR (international normalized ratio): the specific blood test used to measure the time it takes for blood to form a blood clot
- 0.8 – 1.2: normal range for a person not on anticoagulants
  - Too Low (< 2.0): Blood may clot too easily → risk of thrombosis, stroke, or embolism.
  - Too High (> 3.0–3.5): Blood is too thin → increased risk of bleeding, especially dangerous in falls or with trauma.

Liver panel

Albumin: A Protein that assists with moving small molecules such as bilirubin, progesterone, and calcium through the body
- 3-5.5
  - Lab value that indicates nutritional status in the last 12-18 days
  - Below 3 indicates malnutrition
    - Will need to increase overall protein intake
  - Above 55 indicates chronic kidney disease
Pre-albumin: protein that assists with moving small molecules such as bilirubin, progesterone, and calcium through the body.
- 15-36
  - Lab value that indicates nutritional status in the last 1.9 days
    - This is the preferred lab value for nutritional status
  - Below 15 indicates malnutrition
    - Will need to increase overall protein intake
  - Above 36 indicates chronic kidney disease

Renal function

Blood urea nitrogen (BUN): Measures the metabolic function of the kidney and the excretory function of the kidney
- 10-20
  - Below 10 indicates hepatic disease or issues with liver absorption
  - Above 20 indicates a high protein diet, burns- overbody covering a large surface area due to increased metabolism occurring, septic shock
Creatine kinase: Involved in the supply of energy for muscular contraction
- Male: 0.6-1.2
- Female: 0.5-1.1
  - Below normal decreased muscle mass, debilitation
  - Above normal renal disease, rhabdomyolysis, endocrine dysfunction

Definitions

Rhabdomyolysis: Breakdown of muscle mass; excessive muscle tissue is then released into the bloodstream

Cardiac lab values

Troponin:
- Lab value indicates suspected acute coronary ischemic disease
  - Troponin T: < 0.1
  - Troponin: < 0.03
    - Above normal: myocardial injury or myocardial infarction

Arterial blood gases — see further explanation in later chapter 3.3

pH: 7.35- 7.45
Partial pressure of carbon dioxide (PaC0₂): 32-45
Bicarbonate (HCO₃): 22-26

Lipid panel

Low density lipoprotein (LDL - bad cholesterol):
- Creates plaque and occlusions in blood vessels
- Normal <100
  - Low level indicates decreased protein malabsorption, severe burns
  - High levels indicate liver or kidney disease
High density lipoprotein (HDL- good cholesterol):
- Helps to remove excess cholesterol deposits
- Normal: >60 mg/dL
- Below 35 mg/dL indicates increased risk for cardiovascular disease
Triglycerides:
- Produced in the liver and transported to fatty tissue
- Desirable <150
  - Above 150 is hypertriglyceridemia indicates an increased risk for hypothyroidism, myocardial infarction, or cardiovascular disease
  - No specific value- hypotriglyceridemia indicates increased risk for malnutrition
Total cholesterol:
- Main lipid associated with cardiovascular disease
  - <200
    - 200 or higher hypercholesterolemia indicates increased risk for cardiovascular disease
    - No specific value- hypocholesterolemia indicates increased risk for malnutrition

Ankle brachial index (ABI)

Procedure in which the systolic blood pressure is taken from the brachial artery (brachial) and the dorsalis pedis and posterior tibialis arteries (ankle) to assess if peripheral arterial disease is present
- Ratio of ankle blood pressure over brachial blood pressure
  - Summary of Results:
    - 1.4 and above:
      - indicates calcification and vessel hardening
    - 0.9-1.3:
      - Normal, no disease present
    - 0.51-0.89
      - Arterial insufficiency- mild
    - 0.5 and below:
      - Arterial insufficiency- severe
        
        Lower extremity compression contraindicated

EKG Wave Definitions

P wave: atrial depolarization/contraction
PR interval: time for electrical signal from SA node to ventricles
QRS complex: ventricular depolarization/contraction
T wave: ventricular repolarization/relaxation

Reading Electrocardiograms

Assess rhythm regularity, rate, P waves, PR interval, QRS complexes, T wave
Use lead II for clearest pattern
Inverted waves often due to improper lead placement

Heart Rate Calculation (EKG)

Use 6-second strip method: count QRS complexes x 10
Only calculate if rhythm is regular

Sinus Bradycardia

HR < 60 bpm at rest
Common with beta-blockers, elderly
Monitor for dizziness, lightheadedness, pallor; use RPE for activity tolerance

Sinus Tachycardia

HR > 100 bpm at rest
Common during exercise
Stop activity if headache, dizziness, or lightheadedness occur

Atrial Fibrillation (A-fib)

Irregular, tachycardic rhythm; no P wave, irregular rhythm
Monitor vitals closely; use RPE for exercise
Stop activity and notify if new onset

Atrial Flutter (A-flutter)

Regular, rapid atrial contraction; sawtooth P wave pattern
Monitor for rhythm changes; use ECG/telemetry
Start with low-moderate intensity exercise; use RPE

Premature Ventricular Contraction (PVC)

Early ventricular contraction; brief pause in rhythm
Single PVC: continue activity; monitor
Bigeminy or ≥3 PVCs: stop activity; risk for dangerous rhythms

Ventricular Tachycardia

Rapid, irregular ventricular contractions; no atrial contraction
Medical emergency; initiate CPR

Ventricular Fibrillation

Chaotic, quivering ventricles; no effective contraction
Medical emergency; initiate CPR

Vital Signs

Temperature: 97–99.6℉
Resting HR: 60–100 bpm (bradycardia <60, tachycardia >100)
Respiration: 12–20 breaths/min (depression <12, hyperventilation >20)
BP: 120/80 mmHg
O2 saturation: 90–100% (supplement if <90%)

Hematological Lab Values

Hemoglobin: Male 14–18, Female 12–16 (anemia if low, polycythemia if high)
Hematocrit: Male 42–52%, Female 37–47%
Platelets: 150,000–400,000/mm³ (thrombocytopenia if low, thrombocytosis if high)
WBC: 5,000–10,000/mm³ (leukopenia if low, leukocytosis if high)
RBC: Male 4.7–6.1, Female 4.2–5.4
INR: 0.8–1.2 (not on anticoagulants)
- <2.0: risk of thrombosis
- 3.0–3.5: risk of bleeding

Liver Panel

Albumin: 3–5.5 (malnutrition if low, kidney disease if high)
Pre-albumin: 15–36 (preferred for recent nutritional status)

Renal Function

BUN: 10–20 (low: hepatic disease, high: high protein, burns, shock)
Creatine kinase: Male 0.6–1.2, Female 0.5–1.1 (high: renal disease, rhabdomyolysis)

Cardiac Lab Values

Troponin T: <0.1, Troponin: <0.03
- Elevated: myocardial injury/infarction

Arterial Blood Gases

pH: 7.35–7.45
PaCO₂: 32–45
HCO₃⁻: 22–26

Lipid Panel

LDL: <100 (high = atherosclerosis risk)
HDL: >60 (low <35 = increased CVD risk)
Triglycerides: <150 (high = CVD risk)
Total cholesterol: <200 (high = CVD risk)

Ankle Brachial Index (ABI)

1.4+: vessel calcification/hardening
0.9–1.3: normal
0.51–0.89: mild arterial insufficiency
≤0.5: severe arterial insufficiency (no compression)

Electrocaradiograms

How to read electrocardiograms

Definitions

P wave: Atrial depolarization/contraction
PR interval: Represents the time it takes for the electrical signal to move from the ventricles to SA node
QRS complex: Ventricular depolarization/contraction
T wave: Ventricular repolarization/relaxation