exercise rx: exam 2

special considerations for pregnancy

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absolute contraindications for pregnancy

• hemodynamically significant heart disease

• incompetent cervix or cerclage

• intrauterine growth restriction

• multiple gestational at risk of premature labor

• persistent 2nd or 3rd trimester bleeding

• placenta previa after 26 or 28 wks of gestation

• preeclampsia or pregnancy induced hypertension

• premature labor during current pregnancy

• restrictive lung disease

• ruptured membranes

• severe anemia

• uncontrolled or poorly controlled HTX

• uncontrolled thyroid disease

• uncontrolled T1D

• unexplained persistent vaginal bleeding

• other serious CVD, respiratory, or systemic disorder

warning signs to stop exercising during pregnancy

• vaginal bleeding

• loss of amniotic fluid from vagina indicating rupture of membranes

• dyspnea/shortness of breath prior to exertion and/or that does not resolve with rest

• regular + painful uterine contractions

• dizziness, feeling faint, or headache

• chest pain

• calf pain or swelling

• decreased fetal movement

• preterm labor

exercise rx guidelines & recommendations for pregnancy

what exercises to prescribe for pregnancy

HR zones for pregnancy

time + voltage interpretation on rhythm strip

• one small square (vertical) = 0.1 mV

• one large square (vertical) = 0.5 mV

• one small square (horizontal) = 0.04 secs

• one large square (vertical) = 0.2 secs

normal time of each interval + segment

• PR interval = 120-200 ms (3-5 small boxes)

• QRS complex = 80-120 ms (2-2.5 small boxes)

• QT interval = 350-450 ms

genesis, path sequence, & termination of wave of depolarization

• p wave = atrial depolarization

• qrs complex = ventricular depolarization

• t wave = ventricular repolarization

• pr interval = the time from start of atrial depolarization to start of ventricular depolarization

• pr segment = the time from end of atrial depolarization to start of ventricular depolarization

• qt interval = the time from start of ventricular depolarization to end of ventricular repolarization

define P waves, QRS, T waves, PR interval, PR segment, QT interval, ST segment, TP segment, J joint

calculate HR

• large box method

• small box method

• 6 sec method

• which method to default to for arrhythmias

• mall box method

  • 1500/# of small boxes between R waves

• Large box method

  • 300/# of large boxes between R waves

• 6-second method

• count cardiac cycles in a 6-second interval and multiply by 10

define normal sinus rhythm

1. SA node depolarizes

2. depolarization spread through atria

3. delay at AV node

4. bundle of his depolarizaes

5. L & R branches depolarizes

6. purkinje fibers depolarize

7. 60-100 bpm

8. one pa wave for each qrs complex

9. p wave should be positive in lead 2

define tachycardia

100+ bpm at rest

define bradycardia

<60 bpm at rest

define regular rhythm

consistent b/w r waves

define regularly irregular

clear + distinct pattern but every contraction is not spaced equally

define irregularly irregular

erratic pattern + erratic spacing

define arrhythmias (why do they happen)

• any disturbance in the rate, regularity, site of origin, or conduction of the cardiac electrical impulse

  • can be a single, aberrant (or even prolonged pause b/w beats) or a sustained rhythm disturbance that can persist for the lifetime of the patient

  • not every arrhythmia is abnormal (i.e. athletes with abnormal heart rates/rhythms)

• causes

  • hypoxia & ischemia (damage)

  • sympathetic stimulation

  • drugs

  • electrolyte imbalances

  • enlargement

what are the 5 types of arrhythmias

• arrhythmias of sinus origin - electrical activity follows usual conduction pathways but is too fast, too slow, or irregular

• ectopic rhythms - electrical activity originates from a focus other than SA

• reentrant arrhythmias - electrical activity is trapped within an electrical racetrack whose shape & boundaries are determined by anatomic or electrical MI configurations

• conduction block - electrical activity originates from in SA node & follows the usual pathway but is blocked or delayed

• preexcitation syndromes - electrical activity follows anomalous conduction pathways that bypass normal ones providing electrical shortcut

3 basic rules for EKG interpretation

• Depolarization towards the positive pole will get a positive deflection

• Depolarization towards the negative pole will get a negative deflection

• Depolarization directly thru a positive and negative pole will get a biphasic complex

distinguish b/w limb leads + chest leads

• limb: I, II, III, aVR, aVL, aVF

  • inferior: II, III, aVF

  • high lateral: I, aVL

  • forgotten lead: aVR

• chest: V1-V6

  • septal: V1, V2

  • anterior: V3, V4

  • low lateral: V5,V

einthoven’s triangle

• Each side of the triangle represents a distinct bipolar lead measuring the voltage difference (potential difference) between two extremities:

• Lead I: Connects the Right Arm (negative) to the Left Arm (positive) at 0°.

• Lead II: Connects the Right Arm (negative) to the Left Leg (positive) at +60°. (This lead most closely aligns with the heart's normal electrical conduction axis, making it the primary rhythm-monitoring lead).

• Lead III: Connects the Left Arm (negative) to the Left Leg (positive) at +120°

• Electrical Axis: By combining Leads I, II, and III (along with augmented unipolar leads like aVR, aVL, and aVF), clinicians calculate the average direction of the heart's electrical dipole in the frontal plane (normally between -30° and +90°).

• Deflection Direction: Electrical impulses traveling toward a positive electrode produce an upward (positive) deflection on the ECG tracing, while impulses moving away produce a downward (negative) deflection

12 lead ECG placement

hexaxial system - quadrant method

• Normal axis can usually be determined very readily by examining leads I and aVF

  • If the QRS complexes in these leads are positive, then the axis is normal.

• The QRS complexes of leads I and aVF are very positive, consisting of mainly large R waves

  • This implies that the net vector of ventricular depolarization is traveling toward the positive poles of these leads

  • The problem is that Lead I positive and aVF negative doesn't automatically mean abnormal left axis deviation.

causes of axis deviation

• ventricle or atrial hypertrophy

• LBB

• pulmonary conditions (COPD, embolism)

  • usually RAD

• MI

• fascicular block

• obesity + stature

what is angina

• the classic symptom of cardiac ischemia

• described as diffuse chest pain or pressure that may radiate to the neck, arms, or back, or back + may be accompanied by shortness of breath, nausea, vomiting, dizziness, or diaphoresis

• underlying pathophysiology: narrowing of coronary arteries by atherosclerosis

  • impedes blood flow to the heart muscle

• less common causes: aortic stenosis & hypertrophic cardiomyopathy

what is unstable angina

• angina that is present with much less or even no physical exertion & typically lasts much longer & is more severe

what is MI

• blood flow is stopped or limited

  • stemi: ST segment elevation MI

  • non stemi: ST segment does not elevate but most often will be depressed

    • present in MI & unstable angina

how to diagnose MI

• history & physical exam

• cardiac enzyme determination

• ekg

stemi vs non stemi and J-point elevation (what are the norms)

• stemi:

  • during acute stemi the ekg often evolves thru 3 stages

    • T wave peaking followed by T wave inversion

    • ST segment elevation

    • appearance of new Q waves

• non stemi:

  • most often caused by either nonocculsive thrombosis of a major coronary artery or complete occlusion of a small offshoot of one of the major coronary arteries

    • unlike stemis they can involve less than the entire thickness of the heart muscle & can be localized to a particular region by a single coronary vessel like stemis

    • only ekg changes: t wave inversion + st segment depression (no elevation)

• j point

  • common in young healthy people

  • leads V2/V3: st elevation

  • men < 40: >2.5mm

  • women (all ages): >1.5mm

CABGs - on/off pump

• if pump is on:

  • O2-poor blood is directed to machine to become oxygenated and machine pumps blood

  • O2-rich blood is returned to the body skipping the heart & lungs

  • The surgeon can work on a still heart to attach a healthy blood vessel that routes blood around the blockage.

  • Once the grafts are complete, the heart resumes pumping, and circulation is transferred back to the heart.

  • Why use it: The heart is still while the surgeon works, providing a stable surgical field and good visibility

• if pump is off:

  • A mechanical stabilizer reduces movement in the targeted area while the rest of the heart continues beating.

  • The surgeon connects a healthy blood vessel to create a new route around the blocked coronary artery while the heart continues pumping

  • The surgeon checks the graft and completes the operation without needing to restart the heart or disconnect from a heart-lung machine

  • Why use it: It avoids the need for cardiopulmonary bypass and temporarily stopping the heart. However, operating on a moving heart is technically more challenging

CABG: CBPI

• The least invasive method for revascularization is a catheter-based,

  percutaneous intervention

• A doctor inserts a thin, flexible tube called a catheter into a blood vessel, usually in the wrist or groin.

• The catheter is guided toward the coronary arteries using X-ray imaging. Contrast dye helps the doctor see where the artery is narrowed.

• A small balloon at the catheter's tip is inflated at the narrowed area, pressing plaque against the artery wall and widening the opening.

• Often, a mesh stent is expanded inside the artery to help keep it open after the balloon is deflated and removed

CABPG: stent

• Plaque made of cholesterol, fats and other substances builds up inside the coronary artery, reducing blood flow to the heart muscle

• A catheter carries a balloon-mounted stent to the narrowed area. The balloon inflates, expanding the stent and pushing the plaque outward against the artery wall.

• The balloon is deflated and removed, but the stent remains inside the artery, supporting the artery wall and helping maintain the widened opening.

• 2 types

  • Drug-eluting stent (DES): Releases medication that helps prevent excessive tissue growth inside the stent, reducing the chance of the artery narrowing again. These are commonly used today.

  • Bare-metal stent (BMS): A metal mesh tube without a medication coating. Tissue can grow around it as the artery heals, but excessive growth can cause restenosis (re-narrowing).

CABG: exercise testing

• As part of the baseline evaluation, it is highly preferred for a patient to perform a symptom-limited exercise tolerance test (e.g., exercise stress test)

• Although a symptom-limited exercise tolerance test is ideal, it may not always be feasible. In these cases, the 6-minute walk test or other forms of submaximal testing may be conducted

• Information obtained from an exercise test is necessary for developing an individualized, safe, and appropriate exercise prescription and is useful for guiding a patient’s return to work or home/leisure activities

CABG: FITT

LVAD, total artifical heart, heart transplant: FITT