What Is Cardiac Stress Testing? Chad Morsch B.S., ACSM CEP A Cardiac Stress Test is a test used to measure the heart's ability to respond to external stress in a controlled clinical environment. Cardiac stress tests compare the coronary circulation while the patient is at rest with the circulation observed during maximum physical exertion, showing any abnormal blood flow to the heart's muscle tissue This test can be used to diagnose ischemic heart disease, and for patient prognosis after a heart attack or procedure (CABG, STENT, etc.) MODALITIES Treadmill, Bicycle, or Arm Ergometer MODALITIES Treadmill, Bicycle, or Arm Ergometer The level of mechanical stress is progressively increased by adjusting the difficulty (incline, speed, or tension) 1
MODALITIES Treadmill, Bicycle, or Arm Ergometer The level of mechanical stress is progressively increased by adjusting the difficulty (incline, speed, or tension) Intravenous Pharmaceutical MODALITIES Treadmill, Bicycle, or Arm Ergometer The level of mechanical stress is progressively increased by adjusting the difficulty (incline, speed, or tension) Intravenous Pharmaceutical Regadenoson, Adenosine, Persantine, or Dobutamine administered to patient through an IV MODALITIES Treadmill, Bicycle, or Arm Ergometer The level of mechanical stress is progressively increased by adjusting the difficulty (incline, speed, or tension) Intravenous Pharmaceutical Regadenoson, Adenosine, Persantine, or Dobutamine administered to patient through an IV Blood pressure, heart rate, and EKG are analyzed for abnormalities and improper response to exercise or simulated exercise ABSOLUTE CONTRAINDICATIONS Stress Testing 1) Recent significant change in ECG (i.e. MI, ischemia, etc) 2) Unstable angina 3) Uncontrolled cardiac arrhythmias causing symptoms 4) Severe aortic stenosis 5) Uncontrolled heart failure 6) Acute pulmonary embolus 7) Acute myocarditis or pericarditis 8) Suspected/known dissecting aneurysm 9) Acute systemic infection ABSOLUTE CONTRAINDICATIONS Adenosine and Persantine (Dipyridamole) 1) Any condition that would exacerbate bronchospasms (acute asthma, wheezing or congestion) 2) Hypotension, Systolic BP <90 mm Hg 3) Use of dipyridamole or dipyridamole containing medications (e.g., Aggrenox) in the last 48 hours 4) Ingestion of caffeine in last 12 hours 5) Advanced heart block ABSOLUTE CONTRAINDICATIONS Regadenoson 1) Any condition that would exacerbate bronchospasms (acute asthma, wheezing or congestion) 2) Use of dipyridamole or dipyridamole containing medications (e.g., Aggrenox) in the last 48 hours 3) Use of aminophylline in the last 24 hours 4) Use of products containing methylxanthines as well as drugs containing theophylline in the last 12 hours 5) Ingestion of caffeine in last 12 hours 6) Hypotension, Systolic BP <90 mm Hg 7) Known hypersensitivity to adenosine or dipyridamole 8) Advanced heart block 2
PATIENT ANALYSIS How does the patient ambulate Has the patient done this test before Review past medical history Medications Listen to heart and lung sounds Check blood pressure and heart rate Analyze the EKG INDICATIONS FOR STOPPING A STRESS TEST Absolute 1) Drop in systolic BP of >10 mm Hg from baseline pressure when accompanied by ischemia 2) Moderate to severe angina 3) Increasing nervous system symptoms (dizziness) 4) Signs of poor perfusion (cyanosis or pallor) 5) Technical difficulties monitoring BP or EKG 6) Subjects desire to stop 7) Sustained ventricular tachycardia 8) ST elevation > 1mm in leads without diagnostic Q waves (other than V1 or avr) Prepping The Patient Prepping The Patient Obtain IV access Prepping The Patient Obtain IV access You must have access to the bare chest Lifting unbuttoning or removing of shirt Lifting, unbuttoning or removing of shirt Removal of a bra 3
Prepping The Patient Obtain IV access Prepping The Patient Obtain IV access You must have access to the bare chest Lifting, unbuttoning or removing of shirt Removal of a bra You must have access to the bare chest Lifting, unbuttoning or removing of shirt Removal of a bra A Clean site is optimal!! A Clean site is optimal!! Shaving of chest hair Scratching of skin with sandpaper Wiping skin with alcohol Precordial Leads V1 4 th intercostal space immediately to the right of the sternum 12 Lead EKG Electrode Placement V2 4 th intercostal space immediately to the left of the sternum V3 Directly between V2 and V4 V4 5 th intercostal space midclavicular line V5 5 th intercostal space midway between V4 and V6 V6 5 th intercostal space midaxillary line Limb Leads Right Arm Left Arm Right Leg Left Leg Horizontal Plane 4
IT S NOT JUST A BUNCH OF SQUIGGLY LINES THERE ARE WAVES! P Wave Atrial Depolarization QRS Complex Ventricular Depolarization T Wave Ventricular Repolarization U Wave Late Repolarization 5
PR Interval.12 to.20 seconds QRS Interval.04 to.11 seconds CAN YOU DEFINE NORMAL?? QT Interval The time from the beginning of ventricular depolarization to the end of repolarization NORMAL SINUS RHYTHM Heart Rate between 60 100 bpm 6
BRADYCARDIA TACHYCARDIA Heart Rate less than 60 bpm Heart Rate greater than 100 bpm Premature Ventricular Contraction (PVC) Premature Ventricular Contraction (PVC) Most common of the ventricular arrhythmias QRS duration must be at least 0.12 seconds Isolated PVCs are common in normal hearts BIGEMINY TRIGEMINY 7
VENTRICULAR TACHYCARDIA VENTRICULAR TACHYCARDIA A run of three or more PVCs Usually has a rate between 120 200 bpm Premature Atrial Contraction (PAC) Premature Atrial Contraction (PAC) PACs are common phenomena A P wave is visible but differs from sinus P waves Conduct normally to ventricles, normal QRS PAROXYSMAL SUPRAVENTRICULAR TACHYCARDIA (PSVT) PSVT Has a regular rhythm with a HR of 150 250 bpm Narrow QRS Onset is sudden and termination is just as abrupt Valsalva techniques can break the arrhythmia Advanced treatment with Adenosine or Cardioversion 8
FIRST DEGREE AV BLOCK FIRST DEGREE AV BLOCK Caused by a prolonged delay in conduction at the AV node PR interval of 0.2 seconds Every QRS complex is preceded by a P wave SECOND DEGREE AV BLOCK (MOBITZ TYPE I) SECOND DEGREE AV BLOCK (MOBITZ TYPE I) Also known as a Wenckebach Usually due to a block within the AV node Progressive lengthening of each successive PR interval until one P wave fails to conduct through the AV node and is therefore not followed by a QRS complex Sequence then repeats itself SECOND DEGREE AV BLOCK (MOBITZ TYPE II) SECOND DEGREE AV BLOCK (MOBITZ TYPE II) Usually due to a block below the AV node in the HIS bundle Not all atrial impulses are transmitted to the ventricles There is a presence of a dropped beat without progressive lengthening of the PR interval Ratio of conducted beats to non conducted (P waves to QRS complex) beats can vary 9
THIRD DEGREE AV BLOCK (COMPLETE HEART BLOCK) THIRD DEGREE AV BLOCK (COMPLETE HEART BLOCK) Complete AV dissociation P waves and QRS complexes appear at regular intervals but have nothing to do with one another Atria contract about 60 100 bpm Ventricles contract about 30 45 bpm Ventricular complexes will appear wide and bizarre like PVCs ATRIAL FIBRILLATION ATRIAL FIBRILLATION Irregular rhythm QRS will generally appear normal No true P waves are distinguishable Atrium contracting at over 300 bpm Baseline appears to be undulating slightly ASYSTOLE SO WHY DO I NEED TO KNOW ALL THIS? HOW DOES THIS PERTAIN TO MY JOB? 10
Gating of myocardial perfusion patients Gating of myocardial perfusion patients Ejection Fraction Ejection Fraction How it Works The amount of blood in the left and right ventricles pumped out with each heartbeat ECG Gate Camera/ Computer Frame 1 Frame 3 Frame 28 QUANTIFICATION 11
Gating of myocardial perfusion patients Ejection Fraction Emergencies Gating of myocardial perfusion patients Ejection Fraction Emergencies Second set of eyes 12
QUESTIONS? 13