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Nursing 202 . Module B Cardiovascular System Alterations. CARDIAC DYRHYTHMIAS. REVIEW OF CONDUCTION. ELECTRICAL CONDUCTION. SINOATRIAL NODE (SA) INTRAATRIAL FIBER (BACHMAN’S BUNDLE) INTRANODAL TRACTS ATRIOVENTRICULAR (AV) NODE BUNDLE OF HIS (COMMON BUNDLE) BUNDLE BRANCHES
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Nursing 202 Module B Cardiovascular System Alterations
ELECTRICAL CONDUCTION • SINOATRIAL NODE (SA) • INTRAATRIAL FIBER (BACHMAN’S BUNDLE) • INTRANODAL TRACTS • ATRIOVENTRICULAR (AV) NODE • BUNDLE OF HIS (COMMON BUNDLE) • BUNDLE BRANCHES • PURKINJE FIBERS
TERMINOLOGY • WAVE- POSITIVE OR NEGATIVE DEFLECTION GENERALLY BEGINS AND ENDS AT THE BASELINE, REPRESENTING DEPOLARIZATION OR REPOLARIZATION • SEGMENT- LENGTH OF BASELINE BETWEEN 2 WAVES NAMED BY THE WAVE BEFORE AND AFTER • INTERVAL-LENGTH OF A WAVE OR THE LENGTH OF A WAVE WITH THE SEGMENT THAT FOLLOWS • COMPLEX-GROUP OF WAVES THAT FOLLOW ONE AFTER ANOTHER
PR INTERVAL • REPRESENTS TIME FROM THE BEGINNING OF ATRIAL DEPOLARIZATION TO THE BEGINNING OF VENTRICULAR DEPOLARIZATION, MEASURED FROM THE BEGINNING OF THE P WAVE TO THE BEGINNING OF THE QRS COMPLEX (O.12-O.20)
QRS INTERVAL • REPRESENTS THE LENGTH OF TIME FOR DEPOLARIZATION OF THE VENTRICULAR MUSCLE AND IS MEASURED FROM THE BEGINNING OF THE QRS COMPLEX TO THE END OF THE S WAVE, SHOULD MEASURE BETWEEN 0.06-0.10 SECONDS IN DURATION
ST INTERVAL • REPRESENTS THE TOTAL LENGTH OF TIME FOR VENTRICULAR MUSCLE TO BE DEPOLARIZED AND REPOLARIZED, MEASURED FROM THE BEGINNING OF THE QRS COMPLEX TO THE END OF THE T WAVE, NORMAL RANGE IS 0.32-0.42
INHERENT RATES • SA 60-100 • AV JUNCTION 40-60 • VENTRICULAR 20-40
SINUS DYSRHYTHMIA • OCCURS IF THE P - P INTERVAL VARY BY MORE THAN 0.16 . LESS THAN O.16 IS CONSIDERED NORMAL BECAUSE OF THE FLUCTUATION OF THE SYMPATHETIC/ PARASYMPATHETIC STIMULATION • ASSOCIATED WITH RESPIRATION IN CHILDREN AND ELDERLY
SINUS BRADYCARDIA • HR < 60/MIN ARISING FROM THE SA NODE. • IMPULSES FOLLOW THE NORMAL PATHWAY THROUGH THE CONDUCTION SYSTEM • P AND QRS COMPLEXES NORMAL DURATION AND PATTERN
ETIOLOGY • INCREASED VAGAL STIMULATION • MAY BE A NORMAL VARAITION IN ALTHLETES AND HEALTHY YOUG ADULTS • MEDICAL CONDITIONS: • ANOREXIA NERVOSA • ATHEROSCLEROTIC HEART DISEASE • HYPOENDOCRINE STATES • HYPOTHERMIA • INCREASED INTRACRANIAL PRESSURE • MYOCARDIAL INFARCTION • MEDICATIONS: • ANTIHYPERTENSIVES • BETA BLOCKERS • CALCIUM CHANNEL BLOCKERS • CNS DEPRESSANTS • DIGOXIN
SYMPTOMS • SYMPTOMS RELATED TO DECREASE IN CARDIAC OUTPUT • CHEST PRESSURE AND PAIN • DYSPNEA • HYPOTENSION • DIZZINESS • SEIZURES • SYNCOPE
TREATMENT • MANAGEMENT -ONLY IF SYMPTOMATIC- • AIMED AT INCREASING THE HEART RATE • MEDICATIONS • ATROPINE • ISOPROTERENOL • PACEMAKER • SUPRESSION OF THE PARASYMPATHETIC NERVOUS SYSTEM • STIMULATION OF THE SYMPATHETIC NERVOUS SYSTEM
SINUS TACHYCARDIA • HR OF 100-160/ MIN • NORMAL RESPONSE TO SYMPATHETIC NERVOUS SYSTEM STIMULATION • ANY CONDITION THAT PRODUCES AN INCREASE IN METABOLIC RATE
ETIOLOGY • DIET – CAFFEINE • LIFE-STYLE – SMOKING / NICOTINE • MEDICAL CONDITIONS – ANEMIA, HEMORRHAGE, FEVER, HYPOTENSION, PAIN, SHOCK • MEDICATIONS – CENTRAL NERVOUS SYSTEM STIMULANTS • MYOCARDIAL DAMAGE
SYMPTOMS • PRIMARY SYMPTOMS RELATED TO DECREASED CARDIAC OUTPUT • CHEST PRESSURE AND PAIN • DYSPNEA • A CHARACTERISTIC “FLUTTERING” IN THE CHEST • DIZZINESS • SYNCOPE
TREATMENT • ELIMINATE THE CAUSE OF THE TACHYCARDIA • MEDICATIONS: • CALCIUM CHANNEL BLOCKERS • DIGOXIN • BETA BLOCKERS • ANTIANXIETY AGENTS • ADENOSINE • CAROTID MASSAGE
ATRIAL DYSRHYTHMIAS • IMPULSE ARISES OUTSIDE THE SINO ATRIAL NODE • P WAVES DIFFER IN CONFIGURATION • TYPES • WANDERING ATRIAL PACEMAKER • PREMATURE ATRIAL CONTRACTIONS • PAROXYSMAL ATRIAL TACHYCARDIA • ATRIAL FLUTTER • ATRIAL FIBRILLATION
ETIOLOGY • CARDIAC DISEASE • ISCHEMIA • CORONARY ARTERY DISEASE • CONGESTIVE HEART FAILURE • MYOCARDIAL INFARCTION • INCREASED VAGAL STIMULATION • MEDICATIONS
PREMATURE ATRIAL CONTRACTIONS • MOST COMMON ECTOPIC BEAT • OCCURS WHEN IMPULSE IS GENERATED BY AN IRRITABLE AREA OF TISSUE IN THE ATRIA • ABNORMALLY SHAPED P WAVE • QRS COMPLEX NOT AFFECTED
ETIOLOGY • CARDIAC DISEASE • CHRONIC OBSTRUCTIVE PULMONARY DISEASE • MEDICATIONS: CENTRAL NERVOUS SYSTEM STIMULANTS • DIET: CAFFEINE • ELECTROLYTE DISTURBANCES • ANXIETY • LIFE STYLE: EXERCISE, ALCOHOL, NICOTINE
SYMPTOMS • FEELINGS OF PALPITATIONS OR “SKIPPED BEAT”
TREATMENT • TREATMENT DIRECTED TOWARD CAUSE • TREATMENT NOT NECESSARY IF LESS THAN 6 PER MINUTE • DECREASE CAFFEINE CONSUMPTION • DECREASE STRESS • MEDICATIONS: • ANTIANXIETY AGENTS • BETA BLOCKERS • CALCIUM CHANNEL BLOCKERS
PAROXYSMAL ATRIAL TACHYCARDIA • Caused by an irritable area of tissue in the atria that dominates the sinoatrial node and takes over as the pacemaker • Usually preceded by premature atrial contractions • Begin and end abruptly • The raid rate prevents adequate ventricular filling
ETIOLOGY • SAME AS SEEN WITH PREMATURE ATRIAL CONTRACTIONS • NOT USUALLY ASSOCIATED WITH ORGANIC HEART DISEASE
SYMPTOMS • CHEST PAIN • DYSPNEA • HYPOTENSION • PALPITATIONS • WEAK RAPID PULSE • DIZZINESS • SYNCOPE
TREATMENT • CAROTID SINUS PRESSURE • VAGAL NERVE STIMULATION • MEDICATIONS: • DILTIAZEM • VERAPAMIL • DIGOXIN • PROPRANOLOL • PROCAINAMIDE • QUINIDINE • VASOPRESSOR
ATRIAL FLUTTER • ATRIAL ECTOPIC PACER FIRES AT A RATE OF 250-400/ MIN • OCCURS IN A VARIETY OF HEART DISEASES- RHEUMATIC, CORONARY, HYPERTENSIVE, ALSO CARDIOMYOPATHY, HYPOXIA, HEART FAILURE, • MAY BE ASYMPTOMATIC OR HAVE PALPITATIONS • MANAGEMENT- DIGITALIS, BETA BLOCKERS, CALCIUM CHANNEL BLOCKERS, MAY USE CARDIOVERSION
ATRIAL FIBRILLATION • SEVERAL ECTOPIC FOCI CAUSING THE ATRIA TO QUIVER RATHER THAN CONTRACT. • RATE >400 • VENTRICULAR RATE DEPENDS ON THE NUMBER OF IMPULSES CONDUCTED THRU THE AV NODE • MANAGEMENT- DIG., BETA BLOCKERS, CALCIUM CHANNEL BLOCKERS, COUNTERSHOCK
AV HEART BLOCKS • ABNORMAL DELAY IN CONDUCTION OF IMPULSE FROM THE ATRIUM TO THE VENTRICLES • USUALLY ASYMPTOMATIC
FIRST DEGREE • DELAY OCCURS AT THE AV NODE PRODUCING A PROLONGED PR INTERVAL > .20.
ETIOLOGY • COMMON OCCURANCE IN NORMAL HEARTS • CARDIAC DISEASE INCLUDING: • ARTERIOSCLEROTIC HEART DISEASE, MYOCARDITIS, ORGANIC HEART DISEASE, MYOCARDIAL INFARCTION • MEDICATIONS: • BETA BLOCKERS • CALCIUM CHANNEL BLOCKERS • DIGITALIS TOXICITY
TREATMENT • USUALLY NOT NECESSARY UNLESS THE BLOCK THAT IS CAUSED BY MEDICATION THAT CAN BE MODIFIED OR WITHHELD
SECOND DEGREE HEART BLOCK • TYPE I- MOBITZ I OR WENCKEBACH- PROGRESSIVE LENGTHENING OF THE PR INTERVAL UNTIL A QRS COMPLEX IS DROPPED OR NOT CONDUCTED • USUALLY ASYMPTOMATIC • TX- MAYBE NONE, ATROPINE, TEMP. PACER
SECOND DEGREE- TYPE II • EVERY SECOND THIRD OR FOURTH SINUS IMPULSE IS BLOCKED MAY HAVE 2,3,4 Ps TO EACH QRS • MORE SERIOUS- AGGRESSIVE MANAGEMENT TO PREVENT PROGRESSION TO COMPLETE HEART BLOCK • TREATMENT: • PACER • ATROPINE • DOPAMINE FOR SEVERE HYPOTENSION
THIRD DEGREE HEART BLOCK • TOTAL DISASSOCIATION OF ATRIA TO VENTRICLES. VENTRICLES ARE STIMULATED BY A SECONDARY OR ESCAPE BEAT. THE VENTRICULAR RATE WILL BE 40-60 DEPENDING UPON THE LOCATION OF THE VENTRICULAR PACEMAKER • BOTH THE SINUS P WAVE AND THE ESCAPE RHYTHM WILL BE OBVIOUS ON THE ELECTROCARDIOGRAM • ETIOLOGY – • CARDIAC DISEASE • MEDICATIONS – BETA BLOCKERS, CALCIUM CHANNEL BLOCKERS, DIGITALIS TOXICITY • MANIFESTATIONS- FATIGUE, HYPOTENSION, SYNCOPE, HEART FAILURE • TX.- ATROPINE, ISOPROTERENOL, DOPAMINE, PACER
JUNCTIONAL RHYTHMS • RATE 40- 60 • THE DOMINANT PACER OF THE HEART FAILS , RETROGRADE OR BACKWARD STIMULATION OF THE ATRIA- PRODUCING A CHARACTERISTIC P WAVE - MAY BE A NEGATIVE DEFLECTION BEFORE OR AFTER THE QRS COMPLEX OR NO P WAVE AT ALL
ETIOLOGY • CORONARY ARTERY DISEASE • CONGESTIVE HEARAT FAILURE • MYOCARDIAL INFARCTION • CAFFEINE • ANXIETY • ALCOHOL, TOBACCO
SYMPTOMS • FEELINGS OF • PALPITATIONS • FLUTTERING • “SKIPPED BEATS”
MANAGEMENT • TX UNDERLYING CAUSE • MODIFY DIET / LIFESTYLE • REDUCE STRESS • MEDICATIONS : • QUINIDINE
PREMATURE JUNCTIONAL CONTRACTIONS • AN IRRITABLE JUNCTIONAL FOCUS DISCHARGES AN IMPULSE BEFORE THE SINOATRIAL NODE FIRES • ABNORMAL P WAVES CAN PRECEDE, FOLLOW, OR OCCUR SIMULTANEOUSLY WITH THE QRS COMPLEX • VENTRICULAR CONTRACTION IS USUALLY NORMAL • MAY BE FOLLOWED BY AN INCOMPLETE OR COMPENSATORY PAUSE • MAY OCCUR LATE IN THE CYCLE AND IS REFERRED TO AS JUNCTIONAL ESCAPE BEATS • ETIOLOGY, SYMPTOMS, AND TREATMENT IS THE SAME AS LISTED UNDER JUNCTIONAL RHYTHMS
PAROXYSMAL JUNCTIONAL TACHCARDIA • A CLUSTER OF THREE OR MORE PREMATURE JUNCTIONAL CONTRACTIONS FIRING AT A RATE OF MORE THAN 150 BEATS/ MINUTE • ETIOLOGY IS THE SAME AS LISTED UNDER JUNCTIONAL RHYTHMS
SYMPTOMS • MAY BE ASYMPTOMATIC IS RATE IS LESS THAN 150 BEATS/ MINUTE • AT RATES GREATER THAN 150 BEATS/ MINUTE: • CHEST PAIN, PRESSURE, PALPITATIONS, DIZZINESS, SYNCOPE
TREATMENT • MEDICATIONS: • CALCIUM CHANNEL BLOCKER • CENTRAL NERVOUS SYSTEM • DEPRESSANTS • DIGOXIN • VAGAL STIMULATION • CARDIOVERSION
JUNCTIONAL ESCAPE BEATS • BEATS THAT OCCUR WHEN THE AV JUNCTION TAKES OVER THE PACEMAKER ACTIVITY • OCCUR LATE IN THE CYCLE
ETIOLOGY • RHEUMATIC HEART DISEASE • MYOCARDIAL INFARCTION • SINUS ARRHYTHMIAS: • BRADYCARDIA • BLOCK • ARREST • MEDICATIONS • BETA BLOCKERS • CALCIUM CHANNEL BLOCKERS • CENTRAL NERVOUS SYSTEM DEPRESSANTS • DIGOXIN • NARCOTICS • SEDATIVES
SYMPTOMS • MOST ARE ASYMPTOMATIC • FEELINGS OF • PALITATIONS • FLUTTERING • “SKIPPED BEATS”