1、ArrhythmiaDiagnosis and ManagementMohammed R ArafahMBBS FACP FACPC FACC King Saud University Arrhythmia Presentation Palpitation. Dizziness. Chest Pain. Dyspnea. Fainting. Sudden cardiac death.Etiology Physiological Pathological: Valvular heart disease. Ischemic heart disease. Hypertensive heart dis
2、eases. Congenital heart disease. Cardiomyopathies. Carditis. RV dysplasia. Drug related. Pericarditis. Pulmonary diseases. Others.Arrhythmia Assessment ECG 24h Holter monitor Echocardiogram Stress test Coronary angiography Electrophysiology studyMechanism of Arrhthmogensis1.Disorder of impulse forma
3、tion.a)Automaticity.b)Triggered Activity.1)Early after depolarization.2)Delayed after depolarization.2.Disorder of impulse conduction.a)Block Reentry.b)Reflection.3.Combined disorder.SINUS TACHYCARDIARate: 101-160/minP wave: sinusQRS: normalConduction: normalRhythm: regular or slightly irregular The
4、 clinical significance of this dysrhythmia depends on the underlying cause. It may be normal.Underlying causes include: increased circulating catecholamines CHF hypoxia PE increased temperature stress response to pain Treatment includes identification of the underlying cause and correction. SINUS BR
5、ADYCARDIARate: 40-59 bpmP wave: sinusQRS: Normal (.06-.12)Conduction: P-R normal or slightly prolonged at slower ratesRhythm: regular or slightly irregularThis rhythm is often seen as a normal variation in athletes, during sleep, or in response to a vagal maneuver. If the bradycardia becomes slower
6、than the SA node pacemaker, a junctional rhythm may occur. Treatment includes: treat the underlying cause, atropine, isuprel, or artificial pacing if patient is hemodynamically compromised.SINUS ARRHYTHIMIARate: 45-100/bpmP wave: sinusQRS: normalConduction: normalRhythm: regularly irregular The rate
7、 usually increases with inspiration and decreases with expiration. This rhythm is most commonly seen with respiration due to fluctuations in vagal tone.The non respiratory form is present in diseased hearts and sometimes confused with sinus arrset (also known as sinus pause). Treatment is not usuall
8、y required unless symptomatic bradycardia is present. WANDERING PACEMAKERRate: variable depending on the site of the pacemaker; usually 45-100/ bpm. P wave: also variable in morphologyQRS: normalConduction: P-R interval varies depending on the site of the pacemaker Rhythm: irregularThis dysrhythmia
9、may occur in normal hearts as a result of fluctuations in vagal tone. It may also be seen in patients with heart disease or COPD. Wandering atrial pacemaker may also be a precursor to multifocal atrial tachycardia.There is usually no treatment required. PREAMATURE ATRIAL CONTRACTIONSRate: normal or
10、acceleratedP wave: usually have a different morphology than sinus P waves because they originate from an ectopic pacemakerQRS: normalConduction: normal, however the ectopic beats may have a different P-R interval.Rhythm: PACs occur early in the cycle and they usually do not have a complete compensat
11、ory pause. PACs occur normally in a non diseased heart. However, if they occur frequently, they may lead to a more serious atrial dysrhythmias. They can also result from CHF, ischemia and COPD. SINUS PAUSE, ARRESTRate: normalP wave: those that are present are normal QRS: normalConduction: normalRhyt
12、hm: The basic rhythm is regular. The length of the pause is not a multiple of the sinus interval.This may occur in individuals with healthy hearts. It may also occur with increased vagal tone, myocarditis, MI, and digitalis toxicity. If the pause is prolonged, escape beats may occur. The treatment o
13、f this dysrhythmia depends on the underlying cause. If the cause is due to increased vagal tone and the patient is symptomatic, atropine may be indicated. SINOATRIAL BLOCKRate: normal or bradycardiaP wave: those present are normalQRS: normalConduction: normalRhythm: basic rhythm is regular. In a typ
14、e I SA block, the P-P interval shortens until one P wave is dropped.In a type II SA block, the P-P intervals are an exact multiple of the sinus cycle, and are regular before and after the dropped P wave.This usually occurs transiently and produces no symptoms. It may occur in healthy patients with i
15、ncreased vagal tone. It may also be found with CAD, inferior MI, and digitalis toxicity. MULTIFOCAL ATRIAL TACHYCARDIA Rate: 100-250/bpm P wave: two or more ectopic P waves with different morphologies QRS: normal Conduction: P-R intervals vary Rhythm: irregular Multifocal atrial tachycardia (MAT) ma
16、y resemble atrial fibrillation or flutter. It almost always occurs in seriously ill, elderly individuals.COPD is the most common underlying cause. Treatment depends upon the underlying cause. PAROXYSMAL ATRIAL TACHYCARDIARate: atrial 160-250/min: may conduct to ventricles 1:1, or 2:1, 3:1, 4:1 into
17、the presence of a block. P wave: morphology usually varies from sinusQRS: normal (unless associated with aberrant ventricular conduction). Conduction: P-R interval depends on the status of AV conduction tissue and atrial rate: may be normal, abnormal, or not measurable. PAT may occur in the normal a
18、s well as diseased heart. It is a common complication of Wolfe-Parkinson-White syndrome. This rhythm is often transient and doesnt require treatment. However, it can be terminated with vagal maneuvers. Digoxin, antiarrhythmics, and cardioversion may be used. ATRIAL FIBRILLATIONRate: atrial rate usua
19、lly between 400-650/bpm.P wave: not present; wavy baseline is seen instead. QRS: normalConduction: variable AV conduction; if untreated the ventricular response is usually rapid. Rhythm: irregularly irregular. (This is the hallmark of this dysrhythmia). Atrial fibrillation may occur paroxysmally, bu
20、t it often becomes chronic. It is usually associated with COPD, CHF or other heart disease. Treatment includes: Digoxin to slow the AV conduction rate. Cardioversion may also be necessary to terminate this rhythm. PREMATURE JUNCTIONAL CONTRACTION Rate: normal or accelerated. P wave: as with junction
21、al rhythm. QRS: normal Conduction: P-R interval .12 secs if P waves are present. Rhythm: PJCs occur early in the cycle of the baseline rhythm. A full compensatory pause may occur. PJCs may occur in both healthy and diseased hearts. If they are occasional, they are insignificant. If they are frequent
22、, junctional tachycardia may result. Treatment is usually not required. JUCTIONAL TACHYCARDIARate: faster than 60/bpm P wave: as with junctional rhythm.QRS: normal or widened with aberrant ventricular conduction.Conduction: P-R interval usually .12 seconds if presentRhythm: usually regularThe clinic
23、al significance of this rhythm depends upon the basic rhythm disturbance. If the ventricular rate is rapid, cardiac output may decrease. Treatment includes: finding and correcting the underlying cause, vagal maneuvers, verapamil, and cardioversion. JUNCTIONAL ESCAPE RHYTHMRate: 40-60/bpmP wave: inve
24、rted in leads where they are normally upright; this happens when the atrial depolarization wave moves towards a negative (-) lead.P waves may occur before, during or after the QRS, depending on where the pacemaker is located in the AV junction. QRS: normalConduction: P-R interval 0.20 seconds. Rhyth
25、m: regularThis is the most common conduction disturbance. It occurs in both healthy and diseased hearts. First degree AV block can be due to: inferior MI, digitalis toxicity hyperkalemia increased vagal tone acute rheumatic fever myocarditis. Interventions include treating the underlying cause and o
26、bserving for progression to a more advanced AV block. SECOND DEGREE A-V BLOCK MOBITZ TYPE I (WENCKEBACK)Rate: variableP wave: normal morphology with constant P-P intervalQRS: normalConduction: the P-R interval is progressively longer until one P wave is blocked; the cycle begins again following the
27、blocked P wave.Rhythm: irregular Second degree AV block type I occurs in the AV node above the Bundle of His. It is often transient and may be due to acute inferior MI or digitalis toxicity. Treatment is usually not indicated as this rhythm usually produces no symptoms. SECOND DEGREE A-V BLOCK MOBIT
28、Z TYPE IIRate: variableP wave: normal with constant P-P intervals QRS: usually widened because this is usually associated with a bundle branch block. Conduction: P-R interval may be normal or prolonged, but it is constant until one P wave is not conducted to the ventricles. Rhythm: usually regular w
29、hen AV conduction ratios are constantThis block usually occurs below the Bundle of His and may progress into a higher degree block. It can occur after an acute anterior MI due to damage in the bifurcation or the bundle branches. It is more serious than the type I block. Treatment is usually artifici
30、al pacing. THIRD DEGREE (COMPLETE) A-V BLOCKRate: atrial rate is usually normal; ventricular rate is usually less than 70/bpm. The atrial rate is always faster than the ventricular rate. P wave: normal with constant P-P intervals, but not married to the QRS complexes. QRS: may be normal or widened d
31、epending on where the escape pacemaker is located in the conduction systemConduction: atrial and ventricular activities are unrelated due to the complete blocking of the atrial impulses to the ventricles. Rhythm: irregular Complete block of the atrial impulses occurs at the A-V junction, common bund
32、le or bilateral bundle branches. Another pacemaker distal to the block takes over in order to activate the ventricles or ventricular standstill will occur. May be caused by: digitalis toxicity acute infection MI and degeneration of the conductive tissue. Treatment modalities include: external pacing
33、 and atropine for acute, symptomatic episodes and permanent pacing for chronic complete heart block. RIGHT BUNDLE BRANCH BLOCKRate: variableP wave: normal if the underlying rhythm is sinusQRS: wide; 0.12 secondsConduction: This block occurs in the right or left bundle branches or in both. The ventri
34、cle that is supplied by the blocked bundle is depolarized abnormally.Rhythm: regular or irregular depending on the underlying rhythm. Left bundle branch block is more ominous than right bundle branch block because it usually is present in diseased hearts. Both may be caused by hypertension, MI, or c
35、ardiomyopathy. A bifasicular block may progress to third degree heart block. Treatment is artificial pacing for a bifasicular block that is associated with an acute MI. PVC BIGEMNYRate: variableP wave: usually obscured by the QRS, PST or T wave of the PVCQRS: wide 0.12 seconds; morphology is bizarre
36、 with the ST segment and the T wave opposite in polarity. May be multifocal and exhibit different morphologies. Conduction: the impulse originates below the branching portion of the Bundle of His; full compensatory pause is characteristic.Rhythm: irregular. PVCs may occur in singles, couplets or tri
37、plets; or in bigeminy, trigeminy or quadrigeminy.PVCs can occur in healthy hearts. For example, an increase in circulating catecholamines can cause PVCs. They also occur in diseased hearts and from drug (such as digitalis) toxicities. Treatment is required if they are: associated with an acute MI, o
38、ccur as couplets, bigeminy or trigeminy, are multifocal, or are frequent (6/min). Interventions include: lidocaine, pronestyl, or quinidine. VENTRICULAR TACHYCARDIARate: usually between 100 to 220/bpm, but can be as rapid as 250/bpm P wave: obscured if present and are unrelated to the QRS complexes.
39、 QRS: wide and bizarre morphologyConduction: as with PVCsRhythm: three or more ventricular beats in a row; may be regular or irregular. Ventricular tachycardia almost always occurs in diseased hearts.Some common causes are: CAD acute MI digitalis toxicity CHF ventricular aneurysms. Patients are ofte
40、n symptomatic with this dysrhythmia. Ventricular tachycardia can quickly deteriorate into ventricular fibrillation. Electrical countershock is the intervention of choice if the patient is symptomatic and rapidly deteriorating. Some pharmacological interventions include lidocaine, pronestyl, and bret
41、ylium.TORSADE DE POINTESRate: usually between 150 to 220/bpm, P wave: obscured if presentQRS: wide and bizarre morphologyConduction: as with PVCsRhythm: Irregular Paroxysmal starting and stopping suddenly Hallmark of this rhythm is the upward and downward deflection of the QRS complexes around the b
42、aseline. The term Torsade de Pointes means twisting about the points.Consider it V-tach if it doesnt respond to antiarrythmic therapy or treatmentsCaused by: drugs which lengthen the QT interval such as quinidine electrolyte imbalances, particularly hypokalemia myocardial ischemia Treatment: Synchro
43、nized cardioversion is indicated when the patient is unstable. IV magnesium IV Potassium to correct an electrolyte imbalance Overdrive pacing VENTRICULAR FIBRILLATIONRate: unattainableP wave: may be present, but obscured by ventricular wavesQRS: not apparentConduction: chaotic electrical activityRhy
44、thm: chaotic electrical activityThis dysrhythmia results in the absence of cardiac output. Almost always occurs with serious heart disease, especially acute MI. The course of treatment for ventricular fibrillation includes: immediate defibrillation and ACLS protocols. Identification and treatment of
45、 the underlying cause is also needed. IDIOVENTRICULAR RHYTHMRate: 20 to 40 beats per minuteP wave: AbsentQRS: WidenedConduction: Failure of primary pacemakerRhythm: RegularAbsent P waveWidened QRS 0.12 sec.Also called dying heart rhythmPacemaker will most likely be needed to re-establish a normal he
46、art rate.Causes: Myocardial Infarction Pacemaker Failure Metabolic imbalance Myoardial IschemiaTreatment goals include measures to improve cardiac output and establish a normal rhythm and rate.Options include: Atropine PacingCaution: Supressing the ventricular rhythm is contraindicated because that
47、rhythm protects the heart from complete standstill.VENTRICULAR STANDSTILL (ASYSTOLE)Rate: noneP wave: may be seen, but there is no ventricular responseQRS: noneConduction: noneRhythm: noneAsystole occurs most commonly following the termination of atrial, AV junctional or ventricular tachycardias. Th
48、is pause is usually insignificant. Asystole of longer duration in the presence of acute MI and CAD is frequently fatal. Interventions include: CPR, artificial pacing, and atropine. ECG ARTIFACT Artifact occurs when something causes a disruption in monitoring. Some common causes are:AC interference -causes 60 cycle artifact Muscle tremors Respiratory artifact-wandering baseline Loose electrode Broken lead wire
