內(nèi)科護理學 英語 考試資料dysrhythmias課件

1、Dysrhythmia心律失常Properties of cardiac tissue 心臟組織的特性Automaticity 自律性: ability to initiate an impulse spontaneously and continuously.Excitability興奮性: ability to be electrically stimulated.Contractility收縮性: ability to respond mechanically to an impulse.Conductivity傳導性: ability to transmit an impulse al

2、ong a membrane in an orderly manner.Conduction system: a brief review傳導系統(tǒng)P wave begins with the firing of the SA node and represents depolarization去極化 of the fibers of the atria心房, resulting in atrial contraction心房收縮.The QRS complex represents depolarization去極化 of the ventricles心室, resulting in vent

3、ricular contraction心室收縮.The T wave represents repolarization復極of the ventricles心室, or the time at which the ventricles return to the prestimulated state.Conduction system: a brief reviewIntervals波間隔between these waves reflects the lengths of time it takes for the impulses to travel from one area of

4、the heart to the other. The PR interval represents the period during which the impulse spreads through the atria, AV node房室結(jié), bundle of His希氏束, and Purkinje浦肯野纖維.The QRS interval represents the time it takes for depolarization去極化of both ventricles.The QT interval represents the time it takes for com

5、plete depolarization除極and repolarization復極of the ventricles.Classification of Dysrhythmia 心律失常的分類 Abnormal impulse formation 沖動形成異常sinus dysrhythmia 竇性心律失常sinus tachycardia竇性心動過速sinus bradycardia竇性心動過緩竇性心律不齊sinus arrest竇性停搏ectopic rhythm異位心律Passive ectopic rhythm被動性異位心律Escaped 逸博Escapedrhythm 逸博心律Ac

6、tive ectopic rhythm主動性異位心律期前收縮Premature ContractionParoxysmal tachycardia陣發(fā)性心動過速atrial flutter房撲， atrial fibrillation房顫ventricular flutter室撲， ventricular fibrillation室顫 Abnormal impulse comduction 沖動傳導異常Physiological:生理性： interference and separation of AV干擾和房室分離pathological病理性：block of SA竇房傳導阻滯 bloc

7、k of atrial pathway房內(nèi)傳導阻滯block of atrioventricular pathway房室傳導阻滯 Block of bundle branch束支或分支阻滯或室內(nèi)阻滯房室間傳導途徑異常：WPW 預(yù)激綜合征Sinus tachycardia竇性心動過速 Clinical association: It associated with physiological stressors such as exercise, fever, pain, anxiety, hypotension, hypovolemia低血容量 , anemia, hypoxemia低氧血癥

8、, hypoglycemia低血糖癥 , myocardial ischemia, CHF, and thyrotoxicosis甲狀腺毒癥.It also can be affected by drugs such as epinephrine, norepinephrine, caffeine, atropine阿托品 , theophylline茶鹼 , nifedipine硝苯地平 , hydralazine胼酞嗪(降壓藥)Sinus tachycardiaECG characteristicsHR is greater than 100 bpm, rhythm is regular.

9、The P wave is normal, precedes each QRS complex, and has a normal contour and fixed interval.The PR interval is normal and the QRS complex has a normal contour.Sinus bradycardia 竇性心動過緩 Clinical association 臨床聯(lián)系: It occurs in response to hypothermia低體溫 , carotid sinus massage按壓頸動脈竇, increased intraoc

10、ular pressure眼內(nèi)壓 , increased vagal tone迷走神經(jīng)緊張 , and administration of parasympathomimetic擬副交感神經(jīng)藥drugs.Diseases states associated with sinus bradycardia are hypothyroidism甲狀腺機能減退 , increased intracranial pressure顱內(nèi)壓 , obstructive jaundice阻塞性黃疸 and inferior wall MI.Sinus bradycardia 竇性心動過緩 Significanc

11、e意義: The clinical significance of sinus bradycardia depends on how the patients tolerates it hemodynamically. Hypotension with decreased CO may occur in some circumstances.Treatment治療: for the patient with symptoms, administration of atropine阿托品 , and anticholinergic drug抗膽堿能藥 . Pacemaker therapy ma

12、y be required. Sinus bradycardia竇性心動過緩ECG characteristicsHR is less than 60 bpm, rhythm is regular.The P wave precedes each QRS complex.The PR interval is normal and the QRS complex has a normal contour and normal length.Premature Atrial Contraction (PAC)房性期前收縮A PAC is a contraction originating from

13、 an ectopic focus異位病灶 in the atrium in a location other than the sinus node.It originates in the left or right atrium and travels across the atria by an abnormal pathway, creating a distorted P wave.At the AV node房室結(jié), it is stopped (nonconducted PAC), delayed (lengthened PR interval), or conducted n

14、ormally.It moves through the AV node, and in most cases, it is conducted normally through the ventricles.Premature Atrial Contraction (PAC)房性期前收縮ECG characteristicsHR varies and rhythm is irregular.The P wave may be notched缺跡 or have negative deflection逆向的偏轉(zhuǎn), or it may be hidden in the preceding T w

15、ave.QRS is usually normal, if the QRS interval is 0.10 second or longer, abnormal conduction through the ventricle is present.The PR interval may be shorter or longer than normal PR interval, but its within normal limit.Paroxysmal supraventricular tachycardia (PSVT)陣發(fā)性室上性心動過速PAVT is dysrhythmia orig

16、inating in an ectopic focus anywhere above the bifurcation of the bundle of His希氏束分支.PSVT occurring via an accessory pathway旁路途徑is designated as orthodromic順向or antidromic逆向性 tachycardia.Paroxysmal supraventricular tachycardia (PSVT)陣發(fā)性室上性心動過速Clinical association In the normal heart, PSVT is associa

17、ted with overexertion, emotional stress, changes of position, deep inspiration, and stimulation and stimulants such as caffeine and tobacco.In a diseases state, PSVT is associated with rheumatic heart disease, Wolff-Parkinson-White (WPW)預(yù)激綜合癥(conduction via accessory pathways), digitailis intoxicati

18、on, coronary artery disease or cor pulmonary.Paroxysmal supraventricular tachycardia (PSVT)陣發(fā)性室上性心動過速Significance: a prolonged episode and HR greater than 180 bpm may precipitate a decreased CO with hypotension and myocardial ischemia.Treatment: vagal stimulation迷走神經(jīng)刺激: carotid massage按摩頸動脈竇or the V

19、alsalva meneuver Valsalva動作pharmacologic therapy: adenosine腺苷 , verapamil異搏定 , diltiazem地爾硫卓 , digitalis洋地黃 and propranolol心得安 .However, dititalis洋地黃and calcium channel blockers can cause hemodynamic collapse in WPW syndrome.Paroxysmal supraventricular tachycardia (PSVT)陣發(fā)性室上性心動過速ECG characteristics

20、HR is 150 to 250 bpm and rhythm is regular.The P wave is often hidden in the preceding T wave and has an abnormal contour.The PR interval may be prolonged, shortened or normalQRS complex may have a normal or abnormal contour.Atrial flutter 心房撲動Atrial flutter is identified by recurring, regular, sawt

21、ooth-shape flutter waves鋸齒形撲波. Atrial flutter is relatively rare dysrhythmia.Clinical association: It rarely occurs in a normal heart. In disease states, it is associated with CAD, hypertension, mitral valve disorders, pulmonary embolus肺栓塞, cor pulmoale肺心病, cardiomyopathy心肌病, hyperthyroidism甲亢 and t

22、he use of drugs such as digitalis, quinidine奎尼丁 , and epinephrine.Atrial flutter心房撲動Significance: high ventricular rates associated with atrial flutter can decrease CO and cause serious consequence such as heart failure, especially in the patient with underlying heart disease.Treatment:Electrical ca

23、rdioversion心臟電復律may be used to convert the atrial flutter to sinus rhythm in an emergency situation.Drugs used include verapamil 異搏定, digoxin洋地黃 quinidine奎尼丁 , procainamide普魯卡因 and -blockers.Atrial flutter心房撲動ECG characteristicsAtrial rate is 250 to 330 bpm. The ventricular rate varies according ot

24、the conduction ratio. In 2:1 conduction, the ventricular rate is typically found to be apporximately 150 bpm.Atrial rhythm is regular, and ventricular rhythm is usually regular.The P wave is represented by sawtooth waves鋸齒波or F waves.The PR interval is available.QRS complex is normal in contour.Atri

25、al fibrillation心房顫動Significance: It often result in a decrease in CO due to ineffective atrial contractions and a rapid ventricular response.Thrombi血栓may form in the atria as a result of ineffective atrial system may occur as a complication with subsequent development of a stroke.TreatmentIn emergen

26、y situation, cardioversion心臟電復律may be used to convert atrial fibrillation to normal sinus rhythm.Medication used include digoxin洋地黃, verapamil 異搏定, quinidine奎尼丁 , procainamide普魯卡diltiazem地爾硫卓 , and -blockers, flecainide氟卡尼 , propafenone 普羅帕酮 and sotalol施太可鹽酸索他洛爾 .Atrial fibrillation心房顫動ECG character

27、isticsAtrial rate may be as high as 350 to 600 bpm. The ventricular rate varies from as low as 50 to as high as 180 bpm.Atrial rhythm is chaotic混亂, and ventricular rhythm is irregular.The P wave shows fibrillatory waves房顫波(f wave), but no definite P waves can be observed.The PR interval is not measu

28、rable.QRS complex usually has a normal contour.Premature ventricular contractions (PVC)室性期前收縮PVC are initiated from different foci病灶appear different in contour不同輪廓from each other and are call multifocal PVCs多灶性期前收縮.When every other beat is PVC, it is called ventricular bigeminy心室二聯(lián)律.When every third

29、 beat is PVC, it is called ventricular trigeminy心室三聯(lián)律.Premature ventricular contractions (PVC)室性期前收縮Two consecutive PVCs are called couplets成對室性期前收縮.Three consecutive PVCs are called triplets. Ventricular tachycardia室性心動過速occurs when there are three or more consecutive PVCs.When a PVC falls on the T

30、 wave of preceding beat, the R on T phenomenon R波落在T波上現(xiàn)象 occurs and is considered to be dangerous because it may precipitate ventricular tachycardia室性心動過速or ventricular fibrillation心室顫動.Premature ventricular contractions (PVC)室性期前收縮Clinical association: Is associated with stimulation such as caffein

31、e, alcohol, aminophyline氨茶堿, epinephrine and digoxin.They are also associated with hypokelemia低鉀血癥, hypoxia缺氧, fever, exercise, and emotional stress. Disease states associated with PVC includes MI, CHF and CAD.Significance: In heart diseases, depending on frequency, PVCs may reduce the CO and precip

32、itate angina and heart failure. .Treatment: For treating PVCs, lidocaine 利多卡因is the drug of choice. Procainamide普魯卡因 is the second drug of choice if lidocaine is ineffective.Premature ventricular contractions (PVC)室性期前收縮ECG characteristicsHR varies.Rhythm is irregular because of premature beat.A ret

33、rograde逆行P wave is possible, and P wave is rarely visible because is usually lost in the QRS complex of PVC.The PR interval is not measurable.QRS complex is wide and distorted in shape, more than 0.01 second.Ventricular tachycardia 室性心動過速The ECG diagnosis of ventricular tachycardia is made when a ru

34、n of three or more PVCs occurs.The QRS is distorted歪曲in appearance with a duration exceeding 0.12 second and with the ST-T direction pointing to the major QRS deflection.Ventricular tachycardia may be sustained持續(xù)性(lasting longer than 30 seconds) or nonsustained 非持續(xù)性(lasting 30 seconds or less).Ventr

35、icular tachycardiaClinical association: Is associated with acute MI, CAD, significant electrolyte imbalances, cardiomyopathy心肌病, long QT syndrome and coronary reperfusion after thrombolytic therapy溶栓治療后冠狀動脈再灌注.Is also can be observed in the patient who has not heart diseases.Significance: The appear

36、ance of ventricular tachycardia is an ominous不祥sign.It may cause a severe decreased in CO .The result may be pulmonary edema肺水腫, shock休克, and insufficient blood flow to the brain大腦血流量不足. Ventricular fibrillation心室顫動may develop.Ventricular tachycardiaTreatment: If the patient is hemodynamically stabl

37、e, treatment consists of administration of lidocaine利多卡因bolus, Procainamide普魯卡因 is the second drug of choice if lidocaine is ineffective.If the patient is unconscious or hemodynamically unstable, immediate cardioversion心臟電復律is the recommended treatment. Ventricular tachycardiaECG characteristicsVent

38、ricular rate is 110 to 250 bmp.Rhythm may be regular or irregular.The P wave may be dissociated from脫離QRS complex, or it may be buried in QRS complexes or T waves.The PR interval is not measurable.QRS complex is prolonged for more than 0.10 seconds and the QRS complex is distorted.Ventricular fibril

39、lation心室顫動Ventricular fibrillation is a severe derangement of the heart rhythm characterized on the ECG by irregular undulations 波動of varying contour and amplitude.This represents the firing of multiple ectopic foci異位病灶in the ventricle.Mechanically the ventricle is simply “ quivering顫抖”, and no effe

40、ctive contraction or CO occurs.Ventricular fibrillation心室顫動Clinical association: It occurs in acute MI and myocardial ischemia and in chronic diseases such as CAD and cardiomyopathy心肌病.It may occur during cardiac pacing心臟起搏or cardiac catheterization procedures心導管檢查as a result of catheter stimulation

41、 of the ventricle. It may also occur with coronary reperfusion冠狀動脈重新灌注after thrombolytic therapy溶栓治療.Other clinical associations are accidental electrical shock, hyperkalemia高鉀血癥and hypoxemia低氧血癥. Ventricular fibrillation心室顫動Significance: It results in unconsciousness昏迷, absence of pulse, apnea呼吸困難,

42、 and seizure癲癇. If left untreated, the patient with this condition will die.Treatment: Immediate initiation of cardiopulmonary resuscitation心肺復蘇(CPR) and initiation of advanced cardiac life support (ACLS) measures高級心臟生命支持with use of defibrillation and definitive drug therapy.Ventricular fibrillation

43、心室顫動ECG characteristicsHR is not measurable.Rhythm irregular and chaotic.The P is not visible.The PR interval and the QRS interval are not measurable.First degree AV block I度房室傳導阻滯First degree AV block is a type of AV block in which every impulse in conducted to the ventricles but the duration of AV

44、 conduction is prolonged.This is manifested by PR interval greater than 0.20 second. After the impulse moves through the AV node, it is usually conducted normally through the ventricle.First degree AV block I度房室傳導阻滯Clinical association: it is associated with MI, chronic ischemia heart diseases, rheu

45、matic fever風濕熱, hyperthyroidism甲亢, vagal simulation and drugs such as digitalis, -blocker, flecainide 氟卡尼, and IV verapamil 異搏定.Significance: first degree AV block may be a precursor of high degrees of AV block.Treatment: there is no treatment for the first degree AV block.First degree AV block I度房室

46、傳導阻滯ECG characteristicsAtrial rate is normal, and rhythm is regular.The P wave is normal.The PR interval is prolonged for more than 0.20 second.QRS complex usually has a normal contour.Second degree AV block, Type I I型 二度房室傳導阻滯Type I AV block includes a gradual lengthening of the PR interval, and a

47、QRS complex is droped.Type I AV block most commonly occurs in the AV node, but it can also occur in the His-Purkinje System.Clinical association: type I AV block may result from use of drugs such as digoxin or -blocker. It may also be associated with ischemia cardiac disease and other diseases that

48、can slow AV conduction.Second degree AV block, Type I I型 二度房室傳導阻滯Significance: is usually a result of myocardial ischemia in an inferior MI. It is almost transient and is usually well tolerated, however, it may be a warning signal預(yù)警信號of impending significant AV conduction disturbance.Treatment: if t

49、he patient is symptomatic, atropine阿托品is used to increased HR or a temporary pacemaker臨時起搏器may be needed, especially if the patient has an acute MI.Second degree AV block, Type I I型 I I度房室傳導阻滯ECG characteristicsAtrial rate is normal, and ventricular rate may be slower as a result of dropped QRS comp

50、lexs.Ventricular rhythm is irregular.The P wave has a normal contour.The PR interval is progressively lengthens before the nonconducted P wave occurs PR間期逐步延長，直至下一個P波受阻不能下傳至心室， and a QRS complex is dropped.QRS complex has a normal contour.Second degree AV block, Type II I I型 二度房室傳導阻滯Type II AV block

51、 : A P wave is nonconducted, and this almost always occurs when a bundle branch block is present束支傳導阻滯.Type II AV block almost always occurs in the His-Purkinje system浦肯野系統(tǒng).Second-degree block is a more serous type of block in which a certain number of impulse from the sinus node are not conducted t

52、o the ventricles. This occurs in ratios of 2:1 or 3:1, and so on then there are two P waves to one QRS complex, three P waves to one QRS complex.Second degree AV block, Type II I I型 二度房室傳導阻滯Clinical association: Type II AV block is associated with rheumatic風濕性and atherosclerotic粥樣硬化性heart disease, a

53、cute anterior MI, digitalis toxicity.Significance: It often progresses to third degree AV block and is associated with a poor prognosis.It is an indication for therapy with a permanent pacemaker.The reduced HR may result in decreased CO with subsequent hypotension and myocardial ischemia.Second degr

54、ee AV block, Type II I I型 二度房室傳導阻滯Treatment: Temporary treatment before insertion of a permanent pacemaker involves the use of a temporary pacemaker.Drugs such as atropine阿托品, epinephrine or dopamine多巴胺can be tired as temporary measures to increase HR until pacemaker therapy is available.Second degr

55、ee AV block, Type II I I型 二度房室傳導阻滯ECG characteristicsAtrial rate is normal, and ventricular rate depends on the intrinsic rate and the degree of AV block .Sinus rhythm is regular, but ventricular rhythm may irregular.The P wave has a normal contour.The PR interval may be normal or prolonged but rema

56、ins fixed on conducted beats.QRS complex widens more than 0.12 second because of bundle branch block.Third-degree AV block三度房室傳導阻滯Third-degree AV block: is complete heart block, constitutes one form of AV dissociation房室分離in which no impulse from the atria are conducted to the ventricles.The atria ar

57、e stimulated and contract independently of the ventricles.The ventricle rhythm is an escape rhythm, and focus may be above or below the bifuration of the His bundle 希氏束.Third-degree AV block I I I度房室傳導阻滯Clinical association: is associated with fibrosis 纖維化 or calcification 鈣化 of the cardiac conducti

58、on system, CAD, myocarditis, cardiomyopathy心肌炎, open heart surgery and some systemic diseases such as amyloidosis淀粉樣變性and scleroderma硬皮.Significance: it almost always result in decreased CO with subsequent ischemia and heart failure. .Treatment: Temporary pacemaker may be inserted or an external pac

59、emaker applied on an emergency basis in a patient with acute MI.Drugs such as atropine, epinephrine or dopamine can be tired as temporary measures to increase HR and support BP before pacemaker insertion.Third-degree AV block I I I度房室傳導阻滯ECG characteristicsAtrial rate is usually a sinus rate of 60 t

60、o 100 bmp. The ventricular rate depends on the site of block .Atrial and ventricular rhythm are regular, but asynchronous.The P wave has a normal contour.The PR interval is available and there is no time relationship between the P wave and the QRS complex.QRS complex is normal if escape rhythm is in