4INTERPRETING THE ECG P wave: Atrial depolarization. It is normally 2.5mm or less in height0.11seconds or less in duration.QRS COMPLEX: Ventricular depolarization.Less than 0.04 seconds in durationLess than 0.12 seconds in duration.T wave : Ventricular repolarization.U wave: Repolarization of the Purkinje fibers.
5continues…..PR interval: It is measured from the beginning of the P wave to the beginning of the QRS complexIn adults, the PR interval ranges from 0.12 to 0.20 seconds. ST segment: Early ventricular repolarization,QT interval: Total time for ventricular depolarization and repolarization.The QT interval is usually 0.32 to 0.40 secondsTP interval: It is measured from the end of the T wave to the beginning of next P wave.
6CARDIAC ARRHYTHMIACardiac arrhythmia is a conduction disorder that results in an abnormally slow or rapid heart rate or one that dose not proceed through the conduction system in the usual manner.
7TYPES OF ARRHYTHMIAS 1. Sinus Node Arrhythmia: Sinus Bradycardia: An impulse at a slower than normal rate.Etiology:Vagal stimulationDrugs like calcium channel blockers, amiodaron, beta blockers.Altered metabolic states, such as hypothyroidism.Increased intracranial pressure (ICP).The process of ageing,Certain cardiac diseases, such as Myocardial Infarction.
8ECG interpretation Rate: 55 Rhythm: R-R interval is regular. P wave: present for each QRS complex, normal configuration, and each P wave is identical.P-R interval: falls between seconds.QRS complex: normal in appearance, one follows each P wave.QRS interval: seconds.T wave: follows each QRS and is positively conducted.
9Management:Atropine 0.5mg IV push blocks vagal stimulation to the SA node.If the bradycardia persists, a pacemaker may be required.
10Sinus Tachycardia: Etiology: Physiological and psychological stress Sinus tachycardia occurs when the sinus node creates an impulse at a faster than normal rate.Etiology:Physiological and psychological stressMedications that stimulate the sympathetic response
11Clinical Manifestation: Tachycardia, heart rate increases, Syncope Continues…..Clinical Manifestation:Tachycardia, heart rate increases,SyncopeLow blood pressureECG interpretation:Rate: 130P wave: normal configurationP-R interval: between 0.12 and 02.0 or seconds.QRS complex: normal in appearance,QRS interval: 0.06 seconds.T wave: is positively conducted.
12Continues…. Management: Treatment is directed towards elimination of the cause.Beta blockers and calcium channel blockers, although rarely used, may be administered to reduce the heart rate quickly.
13Atrial Arrhythmia: Etiology: a) Premature Atrial Contraction: A premature atrial complex (PAC) is a single ECG complex that occurs when an electrical impulse starts in the atrium before the next normal impulse of the sinus node.Etiology:Stretched atrial myocardium( for example in hypervolemia)Caffine, alcohol, nicotine,AnxietyHyperkalemia(low potassium level)Hypermetabolic states( for example with pregnancy)Atrial ischemia, injury or infarction.Clinical Manifestation:Irregular heart rate.
14Continues… ECG interpretation: Rate & Rhythm: may be slow or fast & will be irregular.P wave: the P wave of the premature contraction will be distorted in shape.P-R interval: may be normal but can also be shortened.QRS complex: with in normal limitsT wave: normally conducted.Management:PACs should be monitored forincreasing frequency.
15Atrial Flutter Etiology: Clinical Manifestation: It is caused by conduction defect in the atrium & causes a rapid regular atrial rate usually between times per minute.Etiology:Patients with chronic obstructive pulmonary disease,valvular diseases,thyrotoxicosis,following open heart surgery & repair of congenital defects.Clinical Manifestation:Chest painShortness of breathLow blood pressure
16Management: ECG interpretation: calcium channel blocker Continues….ECG interpretation:Rate: 250 and 400 bpmRhythm: regular or irregularP wave:not present; instead, it is replaced by a saw-toothed pattern .These waves are also reffered toas “F” waves.QRS complex: normalT wave: present but may be obscured by flutter waves.Management:calcium channel blockerDigitalis and quinidinebeta-adrenergic blocking drugcardioversion.
17Atrial fibrillation Etiology: Its an uncoordinated atrial electrical activation, causes a rapid, disorganized and uncoordinated twitching of atrial musculature.Etiology:advanced age with structural heart diseasesInflammatory or infiltrative diseases &Coronary artery diseases.Hypertension, congenital disorder & heart failure.Diabetes, obesity, hyperthyroidism.Heavy ingestion of alcohol.Clinical Manifestation:Irregular palpitationSymptoms of heart failureHypotension, chest pain, pulmonary edema & altered LOC
18Rhythm: irregular irregularity. Continues….ECG interpretation:Rate: immeasurableRhythm: irregular irregularity.P wave: replaced by fibrillatory waves, called “little f” waves.P-R interval: not measurable.QRS complex: normalT wave: normalManagement:depends on the causes.Electrical cardioversionThe beta-adrenergic blocking drugs or calcium ionAdenosine ( Adenocard)
19Ventricular Tachycardia It is defined as three or more premature ventricular complexes (PVC) in a row, occurring at a rate exceeding 100 bpm.EtiologyAcute MISyndrome of accelerated rhythm that deteriorateMetabolic acidosisElectrolyte disturbance.Toxicity to certain drugsIntake of caffine, nicotine or alcohol.
20Rate & Rhythm : 140 and 220 bpm, regular /irregular. Continues….ECG interpretation:Rate & Rhythm : 140 and 220 bpm, regular /irregular.P wave: not present.P-R interval: not measurable.QRS complex: broad, bizarre in configuration, widened greater than 0.12 second.T wave: deflected opposite to the QRS complex.Management:need antiarrhythmic medications:IV procainamidelidocain used for immediate.Cardioversion
21Ventricular fibrillation Its a rapid, disorganized ventricular rhythm causes ineffective quivering of the ventricles.Etiology:Coronary artery diseases, acute MI.Untreated or unsuccessfully treated ventricular tachycardia, cardiomyopathy, valvular heart diseases.Acid-base and electrolyte abnormalities & electric shock.Clinical Manifestation:Absence of audible heart beat, palpable pulse, respiration.
22Rate: not measurable because of well-formed QRS complex. Continues….ECG interpretation:Rate: not measurable because of well-formed QRS complex.Rhythm: Chaotic.P wave: not present.QRS complex: bizarre, chaotic, no definite contour.T wave: not apparent.Management:immediate defibrillation.If third shock is unsuccessful, begin CPRand administer epinephrine(Adrenalin)
23Ventricular Asystole: Ventricular Asystole is commonly called flat line.Etiology:- Hypoxia Acidosis- Severe electrolyte imbalance - Drug overdose- Hypovolemia Cardiac tamponade- Coronary or pulmonary thrombosis - Trauma- Hypothermia.Clinical Manifestation:Absence of heart beat.No palpable pulseNo respiration
24The immediate treatment is CPR. Continues….ECG interpretation:Absent QRS complexes, confirmed in two different leads, although P wave may be apparent for a short duration. Management:The immediate treatment is CPR.After 2 or 5 cycle CPR, a bolus of IV epinephrine is administered and repeated at 3-5 minute intervals.One dose of vasopressin may be administeredfor the first or second dose of epinephrine.A bolus of IV atropine may also be administeredas soon as possible after the rhythm check.
26Continues….Maze Procedure:This is an open heart surgical procedure for refractory atrial fibrillation. Small transmural incision are made through out the atria. The resulting formation of scar tissue prevents reentry conduction of the electrical impulse.Catheter Ablation Therapy:Catheter Ablation destroy specific cells that are the cause or central conduction route of a tachydysrrhythmia.Ablation is by using radiofrequency, which involves placing a special catheter at or near the origin of the dysrrhythmia. High frequency, low energy sounds waves are passed through the catheter, causing thermal injury and cellular changes that result in localized destruction and scarring.
28CARDIOVERSION & DEFIBRILLATION Principle: an electrical current that depolarize a critical mass of myocardial cells. When the cell repolarize, the sinus node is usually able to recapture its role as the heart’s pacemaker.
29CARDIOVERSIONdelivery of a ‘timed’ electrical current to terminate a tachyarrhythmia.the defibrillator is set to synchronize with the ECG on cardiac monitor.The amount of voltage used varies from J, depending on the defibrillator’s technology, the type and duration of arrhythmia.
30DEFIBRILLATION- Defibrillation is not used for patients who are conscious or have a pulse. - Defibrillation depolarizes a critical mass of myocardial cells all at once; when they depolarize, the sinus node usually recaptures its role as the pacemaker. - The electrical voltage required to defibrillate the heart is usually greater than that required for cardio version.
31DIFFERENCE IN CARDIOVERSION & DEFIBRILLATION In Cardioversion, the delivery of the electrical current is synchronized with the patient’s electrical events; in defibrillation, the delivery of the current is immediate and unsynchronized.
32PACEMAKER THERAPY Types: Pacemakers can be permanent or temporary. A pacemaker is an electronic device that provides electrical stimuli to the heart muscle.Types: Pacemakers can be permanent or temporary.- Temporary pacemakers are used to support patients until they improve or receive a permanent pacemaker.- Temporary pacemakers are used only in hospital setting.
33Complications of Pacemaker Local infection at the entry site of leads for temporary pacing or at the subcutaneous site for permanent generator placement.Pneumothorax.Bleeding & hematomaHemothoraxpericardial effusion & rarely, cardiac temponade.
34Nursing management of patient with an implantable cardiac device: The patient’s heart rate and rhythm are monitored by ECG.The incision site is observed for bleeding, hematoma formation or infection, which may be evidenced by swelling, unusual tenderness, drainage & increased warmth.A chest x-ray is usually taken after procedure.Patient is also assessed for anxiety, depression or angerIn the perioperative & postoperative phases the nurse carefully observes the patient & family with further teaching as needed.
35NURSES RESPONSIBILITIES: When using pads or paddles, we must observe two safety measure.First, good contact must be maintained between the pads or paddles and the patient’s skin (with a conductive medium between them) to prevent electrical current from leaking through the air(arcing) when the defibrillator is discharged.Second, no one is to be in contact with the patient or with anything that is touching the patient when the defibrillator is discharged, to minimize the chance that electrical current is conducted to anyone other than the patient.
36Other nursing care include:- Preventing Infection:Promoting effective coping:Promoting home and community based care: