Coronary Artery Disease Complications Cardiac Arrhythmias/Dysrhythmias  Conduction System  Four Properties of Cardiac Tissue  Automaticity – ability to initiate an impulse  Contractility – ability to respond mechanically to an impulse  Conductivity – ability to transmit an impulse along a membrane in an orderly manner  Excitability – ability to be electrically stimulated

Cardiac Conduction System Specialized neuromuscular tissue  PR Interval:  SA Node – upper R atrium through Bachman’s Bundle  AV Node – internodal pathway  Bundle of His  QRS Complex:  Right and Left Bundle Branches  Purkinje Fibers

Cardiac Conduction

Cardiac Monitoring PQRS Complex

Cardiac Action Potential

Calculating Heart Rate Calculating Heart Rate EKG paper is a grid where time is measured along the horizontal axis. EKG paper is a grid where time is measured along the horizontal axis. Each small square is 1 mm in length and represents 0.04 seconds. Each small square is 1 mm in length and represents 0.04 seconds. Each larger square is 5 mm in length and represents 0.2 seconds. Each larger square is 5 mm in length and represents 0.2 seconds. Voltage is measured along the vertical axis - 10 mm is equal to 1mV in voltage. Voltage is measured along the vertical axis - 10 mm is equal to 1mV in voltage. Heart rate can be easily calculated from the EKG strip: Heart rate can be easily calculated from the EKG strip: When the rhythm is regular: When the rhythm is regular: the heart rate is 300 divided by the number of large squares between the QRS complexes.the heart rate is 300 divided by the number of large squares between the QRS complexes. e.g., if there are 4 large squares between regular QRS complexes, the heart rate is 75 (300/4=75).e.g., if there are 4 large squares between regular QRS complexes, the heart rate is 75 (300/4=75). The second method can be used with an irregular rhythm to estimate the rate: The second method can be used with an irregular rhythm to estimate the rate: Count the number of R waves in a 6 second strip and multiply by 10.Count the number of R waves in a 6 second strip and multiply by 10. e.g., if there are 7 R waves in a 6 second strip, the heart rate is 70 (7x10=70).e.g., if there are 7 R waves in a 6 second strip, the heart rate is 70 (7x10=70).

Cardiac Monitoring Cardiac Rate

Cardiac Monitoring Amplitude / Duration

12 Lead EKG

EKG Leads

12-Lead EKG

Reciprocal EKG Changes

Cardiac Monitoring Chest Lead Placement

Cardiac Monitoring- MCL

Cardiac Monitoring Normal Sinus Rhythm

Cardiac Monitoring PQRS Complex

Cardiac Monitoring Cardiac Rhythm Analysis  Analyze the P waves – rate/rhythm  Analyze the QRS complexes – rate/rhythm  Determine the heart rate  Measure the PR Interval  Measure the QRS duration  Interpret the rhythm  Clinical significance? Hemodynamic status?  Appropriate Tx

Cardiac Monitoring Normal Sinus Rhythm

EKG / Heart Sounds

Cardiac Monitoring Normal Sinus Rhythm Atrial & Ventricular rhythms: regular Atrial & Ventricular rhythms: regular Rate: beats/min Rate: beats/min P waves: present consistent configuration, one P wave prior to each QRS complex P waves: present consistent configuration, one P wave prior to each QRS complex PR interval:.12 –.20 sec and constant PR interval:.12 –.20 sec and constant QRS duration: -.04 to.10 sec and constant QRS duration: -.04 to.10 sec and constant

Cardiac Monitoring Sinus Dysrhythmias

Cardiac Monitoring Sinus Bradycardia  SA Node discharges < 60 beats/ min  Etiology: >parasympathetic stimulation / vagus nerve  Assess: LOC, Orientation, VS, PO, pain, escaped ventricular ectopy  Tx: If patient is symptomatic – raise legs up, move patient, Atropine – ACLS Bradycardia

Cardiac Monitoring Sinus Tachycardia Sinus Bradycardia

Cardiac Monitoring Sinus Tachycardia  SA Node discharge > 100 beats/ min  Etiology: Sympathetic stimulation – normal or abnormal response  Tx: Treat underlying cause  Cardiac Supply Problems  Cardiac Demand Problems  E.g., hypovolemia, hypoxemia, anxiety, pain, anemia, angina  Regular Narrow QRS - Adenosine

Sustained Tachy / Brady Dysrhythmias  Chest discomfort, or pain, radiation to jaw, back, shoulder or upper arm  Restlessness, anxiety, nervousness  Dizziness, syncope  Change in pulse strength, rate, rhythm  Pulse deficit  Shortness of breath, dyspnea  Tachypnea, Orthopnea  Pulmonary rales  S3 or S4 heart sounds  Jugular vein distention  Weakness, fatigue  Pale, cool skin, diaphoresis  Nausea, vomiting  Decreased urine output  Hypotension

Cardiac Monitoring PSVT

Cardiac Monitoring Paroxysmal Supraventricular Narrow QRS Tachycardia (PSVT)  SA Node rate beats/min - M ean 170 beats/min  Etiology: Pre-excitation syndrome, e.g., Wolff- Parkinson White (WPW) Syndrome  Assess: Weakness, fatigue, chest pain, chest wall pain, hypotension, dyspnea, nervousness  Tx: Valsalva maneuvers: bearing down, gagging, ocular pressure, vomiting, carotid sinus massage,  Meds: Adenosine

Cardiac Monitoring Interference

Cardiac Monitoring Atrial Flutter / Fibrillation

Cardiac Monitoring Atrial Fibrillation  Most Common dysrhythmia in the US  Multiple rapid impulses from many atrial foci, rate of /min—depolarize the atrial in a disorganized and chaotic manner – atrial quiver  Results:  No P waves  No atrial contracts  No atrial kick  Irregular ventricular response

Cardiac Monitoring Atrial Fibrillation  Etiology: MI, RHD with Mitral Stenosis, CHF, COPD, Cardiomyopathy, Hyperthyroidism, Pulmonary emboli, WPW Syndrome, Congenital heart disease ** Mural Thrombi – increased risk for pulmonary & systemic thromboemboli to brain & periphery  Assess: VS, PO, Pulse Deficit, chest pain, syncope, hypotension  Symptoms worsen with increased ventricular response

Cardiac Monitoring Atrial Fibrillation  Tx:  TEE – Trans-esophageal echocardiogram  Identifies thrombi on valves  Medications to decrease the ventricular response - Metoprolol (Lopressor)  Oxygen  Prophylactic anticoagulation  Lovenox - Coumadin – long term  Cardioversion

Cardiac Monitoring Atrial Fibrillation  Tx:  Medications to decrease the ventricular response  Narrow QRS irreg rhythm–diltiazem; beta-blockers  Wide QRS reg rhythm – amiodarone  Wide QRS irreg rhythm – digoxin, diltiazem, verapermil, amiodarone  Oxygen  Prophylactic anticoagulation  Cardioversion

Cardiac Monitoring Atrial Fibrillation Cardioversion  Synchronized countershock  50 – 100 Joules  Avoids delivering shock during repolarization  Patent intravenous line  Patient sedated – Versed  Oxygenation  ABC  Assess: VS, PO, Monitor cardiac rate - rhythm  Administer antidysrhythmic medication

Cardiac Monitoring Junctional Escape Rhythm

 Impulse generated from AV nodal cells at the AV Junction  Escape pacemaker  Rate beats/ min  Transient  Assess: Patient hemodynamic stability

Cardiac Monitoring Premature Ventricular Contractions

Cardiac Monitoring NSR – V. Tach – V. Fibrillation

Cardiac Monitoring Ventricular Tachycardia

Cardiac Monitoring Ventricular Dysrhythmias

Cardiac Monitoring Premature Ventricular Contractions

Cardiac Monitoring Premature Ventricular Contractions (PVCs)_  Early ventricular complexes  Followed by compensatory pause  Fit between two NSR beats - interpolated  Unifocal, multifocal, couplet, triplets, bigeminy, trigeminy, quadrigeminy  3+ = ventricular tachycardia  Etiology: myocardial ischemia, <K+, CHF, metabolic acidosis, airway obstruction

Cardiac Monitoring Premature Ventricular Contractions (PVCs/ Ventricular Tachycardia with Pulse  Assess: LOC, hemodynamic status-- continuous cardiac monitoring of rhythm & rate, VS, PO, peripheral perfusion  Tx: Underlying cause + Oxygen, Amiodarone IV bolus / Infusion

V. Tachycardia/V. Fibrillation Pulseless  TX: CPR BLS - Airway, Breathing, Circulation  Shockable Rhythm VT/VF: Defibrillate – Joules  CPR x 5 cycles  Check rhythm – shockable?  Defibrillate (biphasic 200 J / monophasic 360 J  Resume CPR  Epinephine 1 mg IV (repeat q3-5 mins) / Vasopressin  CPR x 5 cycles  Check rhythm – shockable?  Defibrillate (biphasic 200 J / monophasic 360 J  Resume CPR  Antiarrhythmics: amiodarone/lidocaine  Magnesium – torsades de pointes  Advanced Cardiac Life Support  Defibrillation – V Fib / pulseless & polymorphic V tach  Meds:

Cardiac Monitoring V Fib - Agonal Rhythm

Common Causes of Dysrhythmias  Cardiac  Accessory pathways, conduction defects, congestive heart failure, left ventricular hypertrophy, myocardial cell degeneration, myocardial infarction  Other Conditions  Acid-base imbalances, alcohol, coffee, tea, tobacco, connective tissue disorders, drug effects or toxicity, electric shock, electrolyte imbalances, emotional crisis, hypoxia, shock, metabolic disorders (e.g. thyroid), near-drowning, poisoning

Cardiac Monitoring Heart Block 1 st, 2 nd Types I & II

Cardiac Monitoring Heart Blocks

Cardiac Monitoring First Degree AV Block  First Degree AV Block: all sinus impulses eventually reach ventricles  Prolonged PR Interval >.20  Etiology: AV nodal ischemia – right coronary artery (inferior MI); hypokalemia, increased beta-blockers or calcium channel blockers, narcotics, excessive vagal stimulation  Assess: Hemodynamically stable  Tx: withhold offending medication; oxygen; atropine, notify physician; observe

Cardiac Monitoring Second Degree AV Block Mobitz Type I - Wenckebach  Each impulse takes progressively longer  Progressive lengthening of PR Interval  Followed by a dropped beat (missing QRS complex) & a pause  May need temporary transvenous pacer  Etiology: Often transient following anterior / inferior wall MI – may revert to 1 st Degree AV Block  Assess: Hemodynamic stability  Tx: Atropine / May require Temporary Transcutaneous Pacemaker / CPR / ACLS Protocol

Cardiac Monitoring Second Degree AV Block Mobitz Type I - Wenckebach

Cardiac Monitoring Second Degree AV Block Mobitz Type II  Etiology: Infranodal block in one of the bundle branches  Dropped QRS complex without progressive lengthening of PR interval  P wave with no QRS complex following  Random block  May progress to 3 rd Degree AV Block – need for permanent pacer  Assess: Hemodynamic stability  Tx: Atropine / Transcutaneous pacemaker / CPR / ACLS Protocol

Cardiac Monitoring Third Degree AV Block  No sinus impulses conduct to the ventricles  AV dissociation – rate: 40/min  PR interval not constant – no relationship with P and QRS complex  Ventricular pacemaker – may abruptly fail causing ventricular asystole  Etiology: Anterior Wall MI; hypoxemia, electrolyte disturbances, cardiac surgery

Cardiac Monitoring Third Degree AV Block  Assess: Hemodynamic stability  Tx:  CPR  ACLS Protocol  Pacemaker

Cardiac Monitoring Paced Rhythm

Indications for Permanent Pacemaker  Chronic atrial fibrillation with slow ventricular response  Fibrosis or sclerotic changes of the cardiac conduction system  Hypersensitive carotid sinus syndrome  Sick sinus syndrome  Sinus node dysfunction  Tachydysrhythmias  Third-degree AV block

Cardiac Monitoring Ventricular Standstill Pulseless Asystole  CPR  ACLS Protocol  Tx: Atropine, Epinephrine, dopamine

Pulseless Asystole Shockable Rhythm? No – BLS/CPR Shockable Rhythm? No – BLS/CPR Epinephrine 1 mg IV (may repeat q3-5 mins) Epinephrine 1 mg IV (may repeat q3-5 mins) (or one dose of Vasopressin) (or one dose of Vasopressin) Atropine Atropine 5 cycles of CPR 5 cycles of CPR Shockable rhythm? NO - CPR Shockable rhythm? NO - CPR Yes – Pulseless V Fib Yes – Pulseless V Fib

Cardiac Dysrhythmias  ASSESS THE PATIENT  Treat the underlying cause  Support hemodynamically  Emergency Cardiac Medication  CPR  Transcutaneous/Transvenous pacemaker  Information and emotional support to patient & family

New Cardiac Advances  Implantable cardioverter – defibrillator (AICD)  Automatic external defibrillator (AED)  ABCD  Cardiac Ablation Therapy  BLS  ACLS