Chest X-Ray and Cardiac Rhythm Quiz

Diagnostic Imaging and Electrocardiograms

• Learning Objectives:
  • Describe the purpose, procedure, and clinical indications for common diagnostic imaging modalities.
  • Analyze EKG tracings to identify normal and abnormal rhythms and understand their clinical implications.
  • Integrate knowledge of diagnostic imaging and EKG findings to inform clinical decision-making, assess patient readiness for physical therapy, and modify treatment plans based on results.

Outline

• Chest radiographs
• Doppler ultrasound
• Echocardiograms
  • Transthoracic echocardiograms
  • Transesophageal echocardiogram
• Computed Tomography scans
• Computed Tomography Angiogram
• Ventilation/Perfusion Scan
• Pulmonary Function Tests
• Holter monitoring
• Electrocardiogram
  • Sinus Rhythm
  • Irregular Rhythms
  • Escape Beats/Rhythms
  • Premature Contractions
  • Tachy-arrhythmias
  • Ischemia
  • Infarction
  • Pacemakers

Chest Radiographs (Chest X-Ray) (CXR)

• Most common diagnostic examination to produce images of heart, lungs, airways, blood vessels, and the bones of the spine and chest.
• Patient usually stands in front of a plate.
• Most common views are posteroanterior (PA) and lateral.
• Patient is asked to take a few deep breaths and hold it.
• "One view is no views".

Radiodensity

• Air: black appearance (often seen in lungs, trachea, bowels)
• Fat: dark gray appearance (often seen in thicker, adipose tissue)
• Muscle, tendon, organ tissue: appears “neutral” or mid-gray
• Bone:
  • Cancellous or "spongy” bone appears light gray
  • Cortical bone is white
• Contrast media: white
• Metal: white appearance (seen with jewelry, dental fillings, orthopedic hardware)

Systematic Assessment

• Mnemonic system for assessment of images
• Description and location of various organs/tissues on an X-ray image, including airways, bones, cardiac structures, diaphragms, heart edges, lung fields, vessels, gastric bubbles, and hilums.

Normal CXR

• Key anatomical structures visible on a normal chest X-ray, including trachea, hilum, lungs, diaphragm, heart, aortic knuckle, ribs, scapulae, breasts, and bowel gas.

Doppler Ultrasound

• Noninvasive test to measure blood flow through vessels.
• Bounces high-frequency sound waves off RBCs circulating in the blood stream.
• Can estimate how fast blood flows by measuring the rate of change in frequency.
• Types:
  • Doppler ultrasound: assesses how fast the blood flows
  • Color Doppler ultrasound: uses different colors to highlight different directions.

Examples of Doppler Ultrasound

• Direct clot visualization
• Non-compressible popliteal vein
• Color Doppler showing reduced flow in great saphenous vein.

Echocardiograms

• Graphic outline of the heart's movement.
• Provider uses ultrasound from a transducer placed on the chest to take pictures of the heart valves and chambers to evaluate the pumping action of the heart.
• Techniques:
  • 2D ultrasound
  • 3D ultrasound

Transthoracic Echocardiogram vs Transesophageal Echocardiogram

• Transthoracic Echocardiogram (TTE): Transducer placed on outside of the chest, bouncing soundwaves ("echos") appear as pictures that can be saved for review.
• Transesophageal Echocardiogram (TEE): Takes pictures from inside the chest with a small transducer down the throat into the esophagus; patients are sedated.

Computed Tomography (CT) Scan

• Uses X-Rays and computed technology to create detailed cross-sectional images of the body.
• Non-contrast CT: done when visibility would be sufficient for diagnosis, iodine allergy, or kidney problems.
• Contrast-enhanced: iodine-based injection by IV to highlight blood vessels, organs, assists in diagnosing tumors, vascular diseases, or inflammation.

Computed Tomography Angiography (CTA) Scan

• Used for arterial phase, push injection for faster rate, including aorta and pulmonary arteries for PE.
• For diagnosis of PE, sensitivity 96-100%, specificity 89-98%.
• For diagnosis of CAD, sensitivity 97.2-100%, specificity 87.4-89%.

Ventilation/Perfusion (V/Q) Scan

• 2 separate tests (perfusion and ventilation scan) that can be done separately or together.
• Perfusion scan: radioactive albumin injected into a vein, machine scans the lungs as blood flows.
• Ventilation scan: patient breathes in radioactive gas through a mask, machine scans the lungs during the process.
• Used when patients may not be able to tolerate high radiation dose (e.g., pregnancy, contrast dye allergy, renal insufficiency).

Pulmonary Function Tests (PFT)

• Shows how well the lungs are working.
• Resource for predicting values based on age, gender, height.

Holter Monitoring

• Small, wearable device that records the heart's rhythm over 1-2 days.
• Indications: used to spot irregular heartbeats that traditional electrocardiograms haven't picked up.
• Instructions: continue normal activities, avoid getting monitor wet, wear throughout the full time period, even sleeping.

Electrocardiogram (EKG) Interpretation

• Standardized method for EKG interpretation:
  • Rate
  • Rhythm
  • Axis
  • Hypertrophy
  • Infarction

EKG Tracing Recording

• One large box represents 0.2 seconds (200 msec), 5mm of amplitude, one small block represents 0.04 seconds(40 msec) of time, 1mm of amplitude

Overdrive Suppression

• Rapid automaticity (pacemaker activity) suppresses slower automaticity.
• Heart's “fail-safe” mechanism ensures some level of organized contraction in the event of pacemaker failure.
• Junctional = AV junction

Rate

• Determination of beats per minute using visual inspection or a 6-second strip.
• Typically focus on ventricular rate, observing R waves.
• Atrial rate can also be counted.

Visual Inspection Method

• Observing pattern of EKG tracing to determine rate.
• Relative position of R-wave within different segments of tracing corresponds to 300, 150, 100, 75, 60, 50 beats/minute.

6 Second Strip

• Preferred method for irregular rhythms and bradycardias (<60 bpm).
• Count the number of complexes in a 6-second strip and multiply by 10.
• R-waves that fall on the beginning or end of a 6-second strip are not counted

Rhythm

• Check for:
  • P-wave before every QRS
  • QRS after every P-wave
• Determine:
  • P-R interval (normal is ≤ 0.2 seconds)
  • QRS interval (normal is ≤ 0.12 seconds)

Normal Sinus Rhythm

• Key characteristics of normal sinus rhythm on an ECG tracing, such as heart rate, rhythm, P-waves, PR interval, and QRS complex.

Sinus Bradycardia

• Characteristics of sinus bradycardia on an ECG tracing, such as heart rate, rhythm, P-waves, PR interval, and QRS complex (rates <60 bpm).

Sinus Tachycardia

• Characteristics of sinus tachycardia on an ECG tracing, such as heart rate, rhythm, P-waves, PR interval, and QRS complex (rates >100 bpm).

Sinus Arrhythmia

• Normal variation in heart rate related to respiration
• Irregular rhythm but consistent characteristics in P-waves, PR interval, QRS complex.

Dysrhythmias

• Irregular rhythms, escape beats/rhythms, premature contractions, tachycardia, and other detailed descriptions and identifying features.
• Includes specific conditions like atrial fibrillation, atrial fibrillation with rapid ventricular rate (Afib with RVR), ventricular fibrillation, escape beats (atrial, junctional, ventricular), and sinus pause/arrest.

Atrial Fibrillation (Afib)

• Absence of clear P-waves and a wavy baseline where P-waves should be.

Atrial Fibrillation with Rapid Ventricular Rate (Afib with RVR)

• Atrial fibrillation with a rapid ventricular response (>100 bpm), clinical significance and potential consequences.

Ventricular Fibrillation (Vfib)

• Irregular rhythm with wide and bizarre QRS complexes
• Medical emergency requiring immediate treatment (CPR and defibrillation)

Escape (Beats/Rhythms)

• Characteristics of escape beats/rhythms, including location of source (atrial, junctional, ventricular) and relationship to the underlying rhythm.
• Detailed description and differentiating characteristics of various escape beats.

Sinus Pause/Arrest

• Cessation of impulse generation from the SA node, transient cessation (sinus block) or longer-lasting cessation (arrest), and clinical implications of the pause length.

Atrial Escape (Beats/Rhythm)

• Characteristics of atrial escape beats/rhythm, including the presence of a P-wave characteristics, and relationship to the preceding and successive beats/rhythm.

Junctional Escape (Beats/Rhythm)

• Characteristics of junctional escape beats/rhythm, including the lack of a clearly defined P-wave, specific heart rate, and clinical implications.

Ventricular Escape (Beat/Rhythm)

• Characteristics of ventricular escape beats/rhythm, including a wide and bizarre QRS complex and low heart rate, and clinical implications.

Premature Contractions (PACs, PJCs, PVCs)

• Premature beats arising from ectopic foci and their characteristics based on the source (atrial, junctional, ventricular) including the absence/presence of a particular type of wave forms (P waves, PR interval, and QRS complex).
• Different types of premature contractions and associated features.
• Clinical implications of premature contractions, including frequency, presence or absence of symptoms, and need for further evaluation/treatment.
• Specific clinical implications related to various types of contractions: such as atrial contractions (PAC), junctional contractions (PJC), or ventricular contractions (PVC), as well as examples like bigeminy, trigeminy, and quadrigeminy.

Clinical Implications of PVCs

• Criteria to consider when evaluating PVCs as potentially concerning, such as frequency of PVCs per minute, changes in PVC frequency based on activity, the nature of the PVC morphology, clinical signs of symptoms related to perfusion concerns.
• When concerned, PVCs should be evaluated against criteria such as the absence of changes in frequency and morphology based on activity levels, absence of symptoms.

Premature Contraction vs Escape Beats

• How to differentiate between premature contractions and escape beats based on their timing relation to expected sinus beats/rhythm.

Tachy-arrhythmias

• Classification and characteristics of various tachy-arrhythmias (paroxysmal tachycardia, atrial flutter, ventricular flutter, and torsades de pointes), including specific manifestations such as heart rate, rhythm characteristics, absence/ presence of P waves, QRS complexes, other wave forms.

Causes of Paroxysmal Tachycardia

• Common causes of paroxysmal tachycardia based on the location of the source (atrial or ventricular), including possible factors like chemical stimulants (for atrial/junctional), or hypoxia, hypokalemia, and other potentially threatening physiological processes (for ventricular).

Paroxysmal Atrial Tachycardia (PAT)

• A form of supraventricular tachycardia (SVT) characterized by a regular rhythm above 100 bpm and a normal appearance of the QRS complex, and PR interval.

Paroxysmal Ventricular Tachycardia (V-tach)

• A dysrhythmia characterized by a regular rhythm, no discernible P waves, and rates of 150-250 bpm.

Atrial Flutter

• Originates in one irritable atrial focus rate 250-350 bpm.
• May precipitate ventricular rhythm above 100 bpm.
• Can occur in a ratio of 2:1, 3:1, or 4:1 of flutter waves to QRS complexes.

Ventricular Flutter

• Single ventricular focus firing at a rate of 250-350 bpm.
• Making proper diastolic filling impossible, which leads to decay into a lethal dysrhythmia.
• Clinically the same as V-Tach or V-fib

Torsades de Pointes

• "Twisting of points"
• Two competitive irritable ventricular foci.
• Rate is 250-350 bpm.
• Caused by hypomagnesemia, hypokalemia, or Long QT syndrome.

Ventricular Fibrillation

• Rate is > 350 bpm.
• Irregular rhythm with absent P waves and wide/bizarre QRS complexes.
• Medical emergency requiring immediate treatment including CPR and defibrillation.

Ischemia

• Lack of blood flow - not cell death, but represented by inverted T waves or possibly ST segment depression.
• Clinically significant if more than 2 mm.

(Acute) Infarction

• Indicated by ST-segment elevation in leads II, III, and aVF.

(Chronic) Infarction

• Q waves are at least 0.04 seconds long.
• They represent at least 25% of the QRS height and greater than 2mm deep;
• Often seen in v1-v3.

Cardiac Arrest

• Asystole
• Pulse less electrical activity (PEA)

Artificial Pacemakers

• May provide atrial or ventricular pacing, both
• Will display as "pacer spikes" on ECG

Test your knowledge on chest X-ray views, the significance of radiodensity, and the characteristics of cardiac rhythms including escape beats and premature contractions. This quiz covers essential concepts in radiology and cardiology, ideal for students and professionals in the medical field.