Ventricular Dysrhythmias PDF

Ventricular Dysrhytmias WPW: Treatment / Perioperative } Stable orthodromic AVNRT: vagal maneuvers such as carotid sinus massage or Valsalva's maneuver. Arnode } i slow conduction If vagal maneuvers are unsuccessful, adenosine, verapamil, βblockers, or amiodarone may be used as clinically appropr...

Ventricular Dysrhytmias WPW: Treatment / Perioperative } Stable orthodromic AVNRT: vagal maneuvers such as carotid sinus massage or Valsalva's maneuver. Arnode } i slow conduction If vagal maneuvers are unsuccessful, adenosine, verapamil, βblockers, or amiodarone may be used as clinically appropriate. ↳ } through an : arrhyth . In the less common antidromic form of AVNRT, the cardiac impulse is conducted from the atrium to the ventricle through the accessory pathway and returns from the ventricles to the atria via the normal AV node. } i arrythmic ↓ ach. TX: Procainamide slows conduction through accessory pathway Ventricular Dysrhytmias } WPW: Treatment / Perioperative defib : when It no P vabo/Puleles was } Electrical cardioversion indicated if not controlled with drug ↳ to convert back to normal rhyfur therapy } Long term treatment } } ach radiofrequency catheter ablation of the accessory pathway. The procedure is curative in 95% of patients and has a low complication rate. The goal during management of anesthesia is to avoid any event (e.g., increased sympathetic nervous system activity due to pain, anxiety, or hypovolemia) or drug (digoxin, verapamil) that could enhance anterograde conduction of cardiac impulses through an accessory pathway. } Appropriate antidysrhythmic drugs and equipment for electrical cardioversion-defibrillation must be immediately available Prolonged QT Syndrome (LQTS) } } } Definition: prolongation of the QTc exceeding 460 milliseconds. The prolongation of repolarization in LQTS results in a dispersion of refractory periods throughout the myocardium. This abnormality in repolarization allows afterdepolarizations to trigger PVCs. Under certain circumstances, the triggered PVCs initiate a ventricular reentry rhythm manifesting as polymorphic ventricular tachycardia, also known as torsade de pointes (TdP). } electrocardiographically characterized by a "twisting of the peaks" or rotation around the ECG baseline. Prolonged QT Syndrome } Women have longer QT intervals than men. } More pronounced at slower heart rates. } The incidence is higher in women. } The strongest predictor of the risk of syncope or sudden death in patients with congenital prolonged QT syndrome is a QTc exceeding 500 milliseconds. Prolonged QT Syndrome Prolonged QT Syndrome } There are two types of LQTS: congenital and acquired. } Acquired associated to: Haldol } Drugs: antibiotics, antidysrhythmics, antidepressants, and antiemetics. zofran } Electrolyte disturbances: hypokalemia, hypomagnesemia, } severe malnutrition, } hypertrophic cardiomyopathy } subarachnoid hemorrhage. -> ↳ At 1 ICP Prolonged QT Syndrome } Perioperative management } } } } } avoid sympathic stimulation in as arrhyt mias Evaluation of ECG Evaluation of Drugs taking patient Anesthesia plan consider QT prolong drugs } Isoflurane } sevoflurane Haldol Droperidol and other antiemetic drugs also increase the QT interval. Avoid events known to prolong the QT interval should be avoided, such as abrupt increases in sympathetic stimulation associated with preoperative anxiety and noxious stimulation. STOP BradyDysrhytmias } Sinus Bradycardia } } } } HR less than 60 Asymptomatic Response to changes in stimuli Bradydysrhythmias are most commonly caused by: } } SA node dysfunction Dysfunction in the conduction system below the SA node BradyDysrhytmias } SA node dysfunction: Sick Sinus Syndrome } } } Common cause Most common reason for inserting permanent pacemakers if the SA node does not fire, other slower pacemaker cells may take over primary pacemaker function. } } There is normally a pause in electrical activity before a secondary slower pacemaker begins to fire. Ventricular cells below the AV node can act as an ectopic pacemaker but fire at a very slow rate in the range of 30 to 45 beats per minute. BradyDysrhytmias } Perioperative management: } Sinus Bradycardia: No treatment } Avoid excess vagal stimulation / drugs } In symptomatic patients } } } } Atropine: 0.5 mg IV every 3-5 minutes Pacemaker Epinephrine or dopamine may be considered until pacemaker available Glucagon ↑ epi Secretion BradyDysrhytmias } Perioperative management: } Neuroaxial Blockade - nere block Associated to bradycardia } Increased risk of cardiac arrest, if present } Unknown mechanism ¨ Bezold-Jarisch response: paradoxical reflex-induced examen bradycardia resulting from decreased venous return and activation of vagal reflex arcs mediated by baroreceptors and stretch receptors. ¨ Another possible mechanism is the unopposed parasympathetic nervous system activity that results from the anesthetic-induced sympathectomy. } BradyDysrhytmias BradyDysrhytmias } Junctional Rhythm BradyDysrhytmias } Junctional Rhythm: Management } Treat associated conditions } If secondary to halogenated anesthetic no treatment convent -eurance to } TIVA If loss of AV synchrony result in MI, CHF or hypotension then requires management with atropine to increase HR Conduction Disturbances First Degree Heart block } First-degree AV block is defined as a PR interval of longer than 0.2 seconds. } } } } } Each P wave is conducted and has a corresponding QRS complex of normal duration. There is a delay in the passage of the cardiac impulse through the AV node. First-degree AV block can be found in patients with and without structural heart disease. Usually Asymptomatic Increased long term risk of Afib First Degree Heart block First Degree Heart block } Perioperative Management Avoiding any clinical situation or drug that increases vagal tone or slows AV conduction. } Atropine administration can speed conduction of cardiac impulses through the AV node. } In patients with risk factors such as coronary ischemia and systemic infection, these clinical conditions should be treated and medically optimized before surgery. EKT Nat } Digoxin levels should be checked before surgery, and serum potassium should be maintained at normal levels in patients nee receiving digoxin. will prolong AU node conduction } air ↳ PR prolongation Second Degree Heart block } Second-degree AV block can be suspected when a P wave is present without a corresponding QRS complex. } Categories: } Mobitz type I (Wenckebach) block } Mobitz type II block. Second Degree Heart block } Mobitz type I (Wenckebach) block lost QRS Second Degree Heart block } differences - know Mobitz type II ↳ more risk to third degree 1f block than p- P ? P 1 ? P P Second Degree Heart block } Perioperative Management: } If adequate HR and asymptomatic no treatment } Mobitz type II block has a high rate of progression to third-degree heart block and can manifest as a slow escape rhythm insufficient to sustain an acceptable cardiac output. } Placement of a cardiac pacemaker is necessary } Atropine is unlikely to improve bradycardia caused by Mobitz type II block. Third Degree Heart block } } Third-degree heart block, also known as complete heart block, is the complete interruption of AV conduction. Continued activity from an ectopic pacemaker distal to the site of the conduction block. } } Block at AV node: HR=45 to 55 beats per minute and the QRS complex is narrow. Block is below the AV node (infranodal): HR=30 to 40 beats per minute and the QRS complex is wide. Third Degree Heart block - Third Degree Heart block } Perioperative Management } } Antidysrhythmic drugs may suppress the ectopic ventricular pacemaker that is responsible for maintaining the heart rate. Treatment during anesthesia consists of transcutaneous or transvenous cardiac pacing. } } } If the block persists, placement of a permanent cardiac pacemaker is indicated. Preoperative placement of a transvenous pacemaker or the availability of transcutaneous cardiac pacing is necessary before an anesthetic is administered for insertion of a permanent cardiac pacemaker. i bradycardia NAR contractility Isoproterenol may be needed to maintain an acceptable heart rate as temporary measure. treat 4 saer PRintera progressive d constant , prolongation can progress to third degree non conductive pwaves in Bundle Branch Block O roof R block Side ⑫ squareSian } Conduction disturbances at various levels of the HisPurkinje system. } Bundle branch blocks can be chronic or intermittent. } Intraventricular conduction disturbances are usually associated with significant structural heart disease, especially dilated cardiomyopathies. } They are a marker of poor prognosis, both in terms of heart failure and increased mortality. electricity went to ⑫ sidet Bundle Branch Block Bundle Branch Block Saber - que provoca se puede ir Perioperative Management pt } RBBB er } Acute treatment consists of observation and elimination of drugs or clinical factors known to contribute to conduction disturbances. } Pacing capability should be available in the event of progression to HB complete heart block. } LBBB } Treat the underlying disease } LBBB is often asymptomatic, and some patients have LBBB only after a critical heart rate is reached. } The presence of LBBB has special implications if insertion of a pulmonary artery catheter is planned. Third-degree heart block can occur if the central catheter induces RBBB in a patient with preexisting LBBB. Risk 1 18 CVC } most -> H ace Treatment of Dysrhythmias lock descarde Saber Heartb bra - } The majority of antidysrhythmia drugs work by : 1. 2. 3. } - suppressing automaticity in pacemaker cells by decreasing the slope of phase 4 depolarization prolonging the effective refractory period to eliminate reentry circuits facilitating impulse conduction along normal conduction pathways to prevent conduction over a reentrant pathway. ECG changes, such as an increased PR interval or a prolonged QRS duration, are relatively common side effects of antidysrhythmic drug therapy. Saber Treatment of Dysrhythmiasproemeroro) que pare have } Adenosine Stop the } Atropine ↑ AR } Amiodarone Arrayt } } 9 . β-Adrenergic Blockers to mi inset it Sut ↓ HR B Calcium Channel Blockers ↓ BP I mat Treatment of Dysrhythmias } Digoxin } Dopamine i contract } Epinephrine HF irregular , } Isoproterenol to } Lidocaine antiarrh . . + /Nach heart beats THA bradycardia Iv Sib THR Contract . Treatment of Dysrhythmias } Magnesium } Procainamide arrutherine } Sotalol B } } . bluta blocks/SrT Vassopressin -> Line 20% lipid emulsion trator de Lidoca intoxicationbudocoume para Ipodsin" compute vidocaine con Treatment of Dysrhythmias } Transcutaneous Pacing } the chest and back electrodes should be placed over areas of lower skeletal muscle mass, and low-density constant-current impulses should be delivered. } An effective temporizing measure to treat bradydysrhythmias until a transvenous pacemaker can be placed or a more permanent mode of cardiac pacing can be implemented. Treatment of Dysrhythmias } Electrical cardioversion } Defined as the delivery of an electrical discharge synchronized to the R wave of the ECG. } Purpose: recoordinate the electrical pathways of the heart by delivering a single dominant burst of electricity on the R wave of the ECG. } The shock is coordinated with the R wave on the ECG so that the stimulus is not delivered during the relative refractory period of the ventricle—that is, during the T wave—to prevent the R-on-T phenomenon and its associated ventricular tachycardia or ventricular fibrillation } Sedate if awake Treatment of Dysrhythmias } Defibrillation } Used to correct dysrhythmias when it is not possible or reasonable to synchronize the electrical current to the ECG because there is no R wave (no defined QRS complexes) or the patient is pulseless. } The position of the paddles or pads is the same as for cardioversion. } Defibrillation-cardioversion electrodes should not be placed directly over pacemakers or ICD pulse generators. Treatment of Dysrhythmias } Defibrillation } Success depends on good contact, time to act and size of contact area } BiPhasic and monophasic } } } Biphasic uses lower dose No clinical difference If done within 3 minutes survival is above 74% Treatment of Dysrhythmias } Permanently Implanted Cardiac Pacemakers } Pacing Modes } Nomenclature:A five-letter generic code: } The first letter cardiac chamber(s) being paced (A, atrium; V, ventricle; D, dual chamber). The second letter cardiac chamber(s) in which electrical activity is being sensed or detected (O, none; A, atrium; V, ventricle; D, dual). The third letter response to sensed signals (O, none; I, inhibition; T, triggering; D, dual—inhibition and triggering). The fourth letter, R, activation of rate response features,; fifth position denotes the chamber(s) in which multisite pacing is delivered. The most common pacing modes are AAI,VVI, and DDD. } } } } } Treatment of Dysrhythmias } Permanently Implanted Cardiac Pacemakers } Pacing Modes } Asynchronous ¨ ¨ ¨ } } AAI VVI face atrio Dual Chamber } } DDD DDI que medicina donds elta Single Chamber } } AOO VOO DOO P9 ? el use marcapato Treatment of Dysrhythmias acer a cer accr Treatment of Dysrhythmias examta normal & single dual ? ? Surgery in Patients with Pacemaker or ICD } Potential adverse outcomes associated with perioperative CIED-related issues include: } } } } } } hypotension, tachydysrhythmias or bradydysrythmias, myocardial damage, myocardial ischemia or infarction, device malfunction, delay or cancellation of surgery, readmission to a health care facility for management of device malfunction, extended hospital stay, increased patient and hospital costs. Surgery in Patients with Pacemaker or ICD } Preoperative Evaluation } A patient with a preexisting CIED coming for surgery has at least one of three underlying cardiac problems: sustained or intermittent bradydysrhythmia, tachydysrhythmia, or heart failure. Determine type of device present, identification of the clinical indication for the device, appraisal of the patient's degree of dependence on the device (for patients requiring pacing for bradycardia), and assessment of device function. -> most to } common have a caule pace Surgery in Patients with Pacemaker or ICD } Preoperative Evaluation } ECG } Physical Exam } Location of the device } Interrogation of device } Management of Anesthesia } Consider high frequency of coexistent: } } } Coronary Artery Disease HBP Diabetes Surgery in Patients with Pacemaker or ICD } Management of Anesthesia } Most common: interference with device function resulting in EMI } Most common associated procedures: electrocautery, } radiofrequency ablation, } MRI } } } Choice of anesthetic technique does not interfere. Most literature suggests reprogramming the CIED to an asynchronous mode before surgery if the patient is pacemaker dependent. Surgery in Patients with Pacemaker or ICD } Management of Anesthesia } Standardized Monitoring at OR } Avoid succinylcholine to avoid } hyperkat Avoid MRI Scanning REMEMBER - } Co existing diseases are the major source of your management issues TO Be continued next Friday …… } Heart Failure } Cardiomyopathies