ECG Arrhythmias

ECG Arrhythmias Overview

• Focuses on specific arrhythmias, enabling identification on ECGs and understanding implications.
• Builds on prior knowledge.

Core ECG Features and Arrhythmia Identification

• ECG Basics include understanding P waves, QRS complexes, T waves, and the PR interval.
• Common arrhythmias:
  • Premature Ventricular Contractions (PVCs) are characterized by a wide QRS complex and potential ST-segment changes.
  • ST-segment changes can indicate myocardial ischemia through elevation or depression.
  • Bradycardia is slow heart rate, and tachycardia is fast heart rate and understanding their causes and significance.
• Mechanisms and Clinical Significance: explores electrical malfunctions causing arrhythmias and health impacts.
• Diagnostic Implications involves students interpreting ECGs and contributing to the diagnostic process.
• Exercise Considerations: Discusses how specific arrhythmias influence exercise prescription for patient safety.

Learning Activities focus on Identification and Application

• Interactive ECG Interpretation allows students to practice identifying arrhythmias.
• Case Studies apply knowledge to identify arrhythmias and understand clinical significance.

Premature Ventricular Contractions (PVCs)

• Origin: PVCs come from abnormal electrical activity in the ventricles.
• ECG Recognition includes a wide QRS complex.
  • Early PVCs appear closer to the preceding T wave.
  • Late PVCs have a longer distance from the previous beat.
  • Premature P wave may be present.
  • ST-segment changes are potential.
• Clinical Significance: PVCs can be benign or indicate heart disease affecting cardiac output.

ST-Segment Changes

• Location and Significance: The ST-segment reflects the electrical activity between ventricular depolarization (QRS complex) and repolarization (T wave).
• ST-segment Elevation can show myocardial ischemia, possibly indicating acute coronary syndrome (ACS).
• ST-segment Depression can be caused by ischemia, electrolyte imbalances, or medications.
• Context matters ST-segment changes cannot definitively diagnose; other ECG features are needed.

Bradycardia and Tachycardia

• Classify by Heart Rate.
• Bradycardia is a heart rate below 60 bpm, caused by medications, conditioning, or heart conditions can cause fatigue or dizziness.
• Tachycardia is a heart rate above 100 bpm with many causes, some require medical attention.

Interactive Interpretation Exercises

• Learning activities include identifying PVCs and ST-segment changes by QRS complex width, ST-segment position, and heart rate.
• Case Studies focus on real-world scenarios to understand causes, and clinical significance.

Using ECGs

• Understanding ECGs helps interpret them more effectively and contribute to patient care.
• ECGs show abnormalities indicating specific conditions, focusing on PVCs and ST-segment changes.
• Heart rate determines bradycardia and tachycardia classifications.

Practicing ECG Identifications

• Websites/Simulators exist for identifying ECG changes (Medscape ECG Challenge, LITFL ECG Library, Dynamed Plus ECG Simulator).

Important Points When Using ECG Simulators

• Educational purposes only, not for self-diagnosis.
• Consult healthcare professionals for ECG interpretation questions.
• Supervised clinical experience is vital.

ECG Data: The Heart's Conduction System

• The conduction system regulates cardiac contractions for blood circulation.
• Normal Sinus Rhythm (NSR) sets the heart's natural beat via the sinoatrial (SA) node.
• The SA node impulses travel through specialized pathways.
• During NSR, the SA node triggers atrial contraction (blood flow to ventricles).
• The AV node delays impulses.
• Impulses descend, dividing into bundle branches and Purkinje fibers.
• These fibers distribute signals.
• NSR has a regular heart rate of 60-100 bpm.
• NSR ensures optimal cardiac function.

Arrhythmia Defined

• An ECG arrhythmia shows an abnormal heart rhythm via electrocardiography.
• Arrhythmias disrupt the heart's natural rhythm leading to irregular heart rate or rhythm.
• Causes vary.
• Treatment depends on the type and cause like medication, lifestyle changes, or procedures.

Premature Ventricular Contractions (PVCs)

• PVCs happen when ventricles contract prematurely due to electrical impulses from within, not the normal pathway.
• This creates a wide QRS complex, showing premature contraction. Commonly originates in the ventricles.

Cardiac Rhythm

• Electrical impulses start from the sinoatrial (SA) node, travel to the AV node, then down the bundle of His and Purkinje fibers to stimulate ventricular contraction for efficient blood ejection.
• PVCs: Electrical impulse starts in ventricles leading to early ventricular contraction and disruptions to rhythm

PVC Causes

• Various factors, like cardiac conditions, electrolyte issues, medications, and lifestyle.
• May be asymptomatic, and can cause palpitations, skipped beats, chest discomfort, or shortness of breath.
• Rapid PVCs causes ventricular tachycardia.
• Interventions include cardioversion or defibrillation.

PVC Treatment

• Treatment depends on frequency, severity, and cause.
• Infrequent PVCs need no treatment.
• Frequent PVCs are treated with beta-blockers or calcium channel blockers.
• Catheter ablation targets the source of PVCs.

Unifocal PVCs

• Arise from a single spot in the ventricles.
• All premature beats look similar on the ECG.
• Connected to heart conditions or risk factors.
• Monitored closely.

Multifocal PVCs

• Come from multiple ventricular sites.
• Show different shapes on the ECG. Considered concerning.
• Linked to severe heart issues.
• Require diagnostic evaluations and management.

Multifocal PVC: Distinguishing From Ventricular Tachycardia

• PVCs are isolated, with a short duration and intermittent nature.
• Ventricular tachycardia (VT) features a rapid succession of PVCs surpassing 100 bpm.
• PVC symptoms: palpitations.
• VT causes hemodynamic instability leading to dizziness, syncope, or cardiac arrest.
• PVCs are benign, and VT requires prompt treatment.

The ST Segment

• ECG acts like a movie of heart's electrical activity. ST-segment focuses on muscle cell relaxation.
• Look for the QRS complex. ST segment starts after the end of the QRS complex, until the beginning of the T wave.
• The ST segment should be flat, if electricity is minimal (isoelectric). If this happens, the heart muscle is receiving enough oxygen to function correctly.

Decoding the ST Segment

• Flat ST segment means electrical calm.
• ST-segment Elevation: Indicates myocardial ischemia, or lack of oxygen to heart muscle.
• ST-segment Depression: Indicates reduced flow to the heart muscle.
• Myocardial ischemia or infarction (heart attack) is a significant case.

Decoding ST Segment Depression

• Upsloping ST-segment depression: ST dips down then curves upwards to T wave which indicates ischemia.
• Downsloping ST-segment depression steep, indicating ongoing ischemia.
• Horizontal ST-segment depression dips down and remains flat which indicates ischemia, electrolyte imbalances, or certain medications.

Decoding ST-Segment Slopes: A Practical Approach

• 80 Millisecond Rule: Measure 80 ms outwards from the J point.
• Compare Heights: If the ST segment at the 80 ms mark is higher than the J point its upsloping. If its lower, it's downsloping.
• Measurement Units: ST-segment change is in 0.5 mm increments.
• Reference Point: Measure the distance between the ST segment and the baseline.

ST-segment Elevation: A Red Flag

• ST-segment elevation is a sign of an acute myocardial infarction (AMI).
• Exercise professionals should know that exercise is contraindicated as of 2022 ACSM guidelines, including submaximal exercise testing (submax GXT).
• Exceeding 1.0 mm on GXT is a contraindication and GXT should be terminated.
• Safe cool down period for patient is mandatory, with low intensity speed (2.0 km/h) and 0% to prevent blood from pooling in lags.
• Exercise can put extra stress on heart during an AMI, focusing on safety and care is very important.

Simplified ECG Analysis Steps

• Rate and Rhythm: Count QRS complexes for heart rate. Regularity indicates normal rhythm.
• P Waves: check if present before each QRS complex, if not it indicates arrhythmia or conduction issues
• QRS Complex: Width indicates normal or abnormal conduction.
• ST-segment: Look for elevation or depression, with ST segment should be relatively flat.
• T Wave: Morphology should be upright in most leads.
• Note: ECG interpretation needs training and experience.
• Additional tips when needed: Use ruler to measure intervals, refer to lead replacements to ensure proper interpretation.

Module 3 Topics Summary

• Explores ECG arrhythmias, serving as a window into potential life threatening heart issues.
• Provides the skills to interpret ECGs, and assist with tailoring exercise protocols.
• Equips information for success in clinical research, especially specializing in exercise physiology for cardiac patients.
• Contributes knowledge for cardiology and promotion of heart health.

Atrioventricular Block (AV Block)

• Affects electrical signals from the atria to the ventricles.
• Caused by damage/disease in the heart's electrical conduction system.
• There are three types of AV Block.

First-Degree AV Block

• Delay in signal conduction, but all signals get transmitted >.20 ms.
• Asymptomatic=no treatment needed.
• Commonly seen in fit endurance athletes.

Second-Degree AV Block

• Electrical signal fails to reach the ventricles intermittently.
• Type 1 "Wenckebach block" is a progressive lengthening until one impulse is dropped.
• Type 2 "Mobitz type II" includes failure for P wave to reach ventricles which is more serious, leading to contraindications in exercise testing/exercise.
• Symptoms include dizziness, fainting, SOB.

Third-Degree AV Block

• Complete interruption between atria/ventricles (complete heart block). Symptoms include dizziness, fainting, SOB. Requires medical attention.
• Requires a pacemaker to regulate.

AV Block Points and Guidelines:

• In rare cases, a complete AVB may develop during an exercise test.
• First degree AVB does not contraindicate exercise, but it may be a mortality risk factor for mortality in people with stable coronary disease.

Clients with CHF: Understanding and Managing

• Heart failure=heart cannot pump blood effectively and is associated with right and left sided failures leading to congestive heart failure.
• Adaptive mechanisms attempt to maintain cardiac function.
• General signs and symptoms of heart failure include shortness of breath, fatigue, cyanosis, tachycardia and ankle oedema.

Right Sided Heart Failure

• Represents inability to pump blood into pulmonary circulation.
• Peripheral oedema in the lower extremities and congestion of abdominal organs
• Occurs commonly from cor pulmonale and results in decreased blood flow in the lungs, resulting in decreased blood oxygenation, systemic blood pressure and left sided heart failure

Left Sided Heart Failure

• Represents inability to move blood from the pulmonary circulation into systemic circulation.
• The left ventricle enlarges, resulting in blood congestion in the heart and lungs.
• Backward effect can cause increased pulmonary congestion causing lung stiffness that is hard for expansion for gas exchange that leads to dyspnoea.

Congestive Heart Failure (CHF)

• Connected, with both sides failing and diagnostic method showing MRI or echocardiograph.
• Treatment Goals include adjusting to reduced cardiac reserve, improve cardiac function, minimize discomfort, and improve quality of life.
• Reduces demands of the heart with nitrates, vascular/arterial, diuretics, and oxygen therapy.

Heart Failure Precarious Info

• Cannot be reversed, but assistance is given for better quality of life and to live longer.
• Occurs when the heart cannot pump enough blood around the body to satisfy its requirements and may be caused by various risk factors. (myocarditis, cardiomyopathy, congenital heart disease, valve disease, toxins, chronic conditions diabetes HIV, nutritional deficiencies, diseases like sarcoidosis).
• Treatment consist of medication, physical activity, implantable devices, surgery.
• When assisting for clients with heart failure and CHF, exercise should be designed considering the SNS triggering more stress hormones to be released that increases the heart's workload.

Chronic Heart Failure (CHF) Treatment

• Managed through exercise in reducing maladaptations in myocardial/skeletal muscle function.
• Consisted with low to moderate intensity endurance exercise, and individual resistance training 2x per week.
• Volume and intensity should depend on the syndrome severity, however, monitoring prior and during exercise is appropriate for exercising.

Clinical Testing Diagnosing with CHF

• Diagnosing with CE testing is valuable particularly with patients show equivocal signs and symptoms.
• EP uses VO2 max, HR, and gas exchange to assess the functional capacity of the patient's CVD
• Helping with risk stratification (identifying patients at a higher risk of adverse events) to design personalized safe programs.
• Monitoring Patient's Response allows to adjust an optimal program. Prescribing an appropriate exercise prescription will improve patient's functional capacity and reduce risk of hospitalization.

Most Common Medically Prescribed Medications

• Diuretics check BP PRIOR and following session.
• Patients may have low BPs.
• The American College of Sports Medicine (2021) states that exercise testing is safe in individuals with congestive heart failure with a reduced ejection fraction (HFeEF).
• Patients with HFeEF will have low peak HR response

Exercise Program Info

• Lower HR is due to impaired HR, SV and cardiac output responses.

Exercise Precaution w/ Patients with CHF

• HR target from peak during symptom-limited GXT from cardiologist.
• If GXT not available the patient must do 20-30 BPM above resting HR
• RPE with the measurement, the patient should equal 11-14
• For maximal test patients must to be at intervals such as 30sec- 4mins at 85% heart rate range that are intercepted by 50-70% volume increase is mandatory over time.

Heart Pacemakers

• Pacemakers support controlling the hearts electrical system for electrical synchronization between atria and ventricles (referred to as "duel lead pacemaker"). Combined patients often consist of pacemaker and ICD.
• Pacemaker Types:
  • Rate responsive help increase/decrease to match level of physical activity and movement.
  • Demand Pacemakers kick in when the hearts stops or is too slow, with pacing electrical activity. (complete heart block)

Revascularization Procedures Overview

• Restore good blood flow to the effective areas.
• The EP helps assist the patient in the potential related exercise complications and assist and coach the patient with safety protocols for activity.

Common Revascularization Procedures

• CABG is a medical process using good blood vessels as grafts to bypass narrowed.
• PTCA assists with a catheter to increase blood.
• Used a stint to hold blood flow after angioplasty.
• PA Surgery helps good blood flow for effective extremity.
• Carotid Endarterectomy assist in reducing plaque buildup for good blood flow to brain.
• EVAR assists with a stent to reinforce good blood flow.

(CABG) Coronary Artery Bypass Grafting

• Enhances blood flow in areas of obstructed vessels. It is high recommended that if any individual is at high risk for cardiac problems, CABG becomes a procedure to offset severe issues down the road...
• Open heart is commonly practiced but alternative measures are in practice to avoid this if possible.

(PTCA)

• Provides a minimally invasive treatment for an artery as a balloon is in place to increase the potential blood/lumen size by use of medical tool and methods commonly used. As a stint will become in place for support.
• Less dangerous than Open Heart which is a great option for individuals.

Heart Stent

• Inserts the metal to encourage good artery health.
• Medication and lifestyle is assisted to treat issues.

Common Medication

• Nitrolingual
• ACSM with BP HR with SIDE EFFECTS

Patient Evaluation with Submaximal Evaluation Tool

• Evaluates:HR BP SPO2 RPE RPD

Testing Protocols

• Bike testing with evaluation responses during intense submaximal graded exercise.
• Low work to high work.

YMCA Bike Test

• Increments work load depending on HR and should be for 3 min til 85% is meet-American College Sports Medicine GXT

Modified Cycle

• Consider standard increment increase with 100 wat intensity- increase intensity 40 following the 3 min.
• Incorporate 60 second active recovery following-adjust watts with clinical patients.

For a more intense option that is an Individualized Cycle Test

GEQFF (Case Study)

• CAD with Hypertension-45 watts every 3 mins HR was110 BPM.

Monark cycle

• Most Clinic are electronic, but with the assessment, you can use watts to find POTENTIALpeakVO2 test or level setting.

Treadmill Protocols

• BRUCE/Modified

Bruce Protocol

• A treadmill to gradual increase in both speed and incline. Continue when max efforts is met- American College of Sports Medicine GXT protocol.

Modified Bruce Protocol

• Designed to be less intense to cater around for a smaller increment progression.

Naughton TM

• Has intense with the incremental workload-has TM where the exercise increments stages is shorter.

Patient Test

• The proper submax protocols depends on a patient's individual health.

Exercise Prescription for Cardiac Rehab

• An outpatient (cardiac issues) and inpatient (revascularization) must consider both strength/resistance to balance through cardiac and rehab procedures.
• American College Sports Medicine is followed with guidelines and prescription.

CV Rehabilitation

• Empower the patient to reclaim control by regular physical activity, with tailored modification and exercise- with the consultation with healthcare professional.

Post Open Chest Precaution Exercise

• The proper patient approach that assists in specific exercise provided by hospital, is commonly used to assist cardiac rehab clients with cardiac complications and safety. Is mandatory to follow.

Nervousness is Common and to Follow Guidance w/ Hospital

• Exercise with a professional is necessary.
• Consult from a local MD
• Cardiac Rehabilitation supports individuals and provides individuals to be consistent with their body and mind- by improving the quality of life of the patient

Consideration with starting with weight

• The heart should always consider to starting with a weight that is light that assist with symmetrical movement so no stress on sternum-the process with weight should also consider the guidance with physical specialist for 12 week rehab course.

Important Point for Reassurance

• If you have any discomfort consider it right away and it can be common to be fatigue to do an increase in levels and resistance

Start small and increase overtime

• By use of the ACSM protocol/guideline the patient should overtime see changes that will assist cardiac strength and activity.