* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Supraventricular Arrhythmias
Survey
Document related concepts
Remote ischemic conditioning wikipedia , lookup
Heart failure wikipedia , lookup
Management of acute coronary syndrome wikipedia , lookup
Lutembacher's syndrome wikipedia , lookup
Antihypertensive drug wikipedia , lookup
Cardiothoracic surgery wikipedia , lookup
Coronary artery disease wikipedia , lookup
Cardiac contractility modulation wikipedia , lookup
Myocardial infarction wikipedia , lookup
Cardiac surgery wikipedia , lookup
Quantium Medical Cardiac Output wikipedia , lookup
Arrhythmogenic right ventricular dysplasia wikipedia , lookup
Electrocardiography wikipedia , lookup
Ventricular fibrillation wikipedia , lookup
Transcript
Supraventricular Arrhythmias Jennifer Salotto, MD Trauma, Acute Care Surgery, & Surgical Critical Care Fellow SCC Lecture Series January 2015 Objectives: Review anatomy and physiology of cardiac conduction system. Define supraventricular arrhythmia. Describe the initial approach to a patient with an arrhythmia. Discuss diagnosis and treatment options for patients with atrial fibrillation, atrial flutter, and supraventricular tachycardia. Cardiac arrhythmias Caused by a derangement in electrical impulse initiation, conduction, or both Classified as: Brady (<60 bpm) or tachy (>100bpm) Tachyarrythmias categorized by location of origin of irregular impulse: Above the AV node (supraventricular) Below the AV node (ventricular) Cardiac Conduction System. SA node= pacemaker Generates cardiac impulse, automaticity Jxn SVC and RA RCA in 60% Cardiac Conduction System. SA node -> atria ->atrioventricular node AV node controls atrial impulse tx to ventricles, thus regulating speed of atrial and ventricular contractions Cardiac Conduction System. AV node to intraventricular septum via bundle of His R, L BB Purkinje fibers Activate ventricles Cardiac Conduction System. Sympathetic: Epinephrine, NE act on adrenergic receptors. Faster conduction, Increased impulse generation. Parasympathetic: Vagus nerve releases acetylcholine, which acts on muscarinic receptors. Slows sinus node impulse generation and conduction thru AV node. Heavy innervation from sympathetic and parasympathetic nervous system determines heart rate and speed of contraction Factors promoting arrhythmias in surgical pts: Iatrogenic Factors: Patient Factors: volume overload Underlying structural direct manipulation of the abnormalities CHF CAD heart intravascular catheters drugs cardiopulmonary bypass Other: Electrolyte imbalances Excess sympathetic tone What is supraventricular arrhythmia? Abnormal impulse arises above bundle of His Require atrial or AV nodal tissue to initiate & maintain Supraventricular arrhythmias Atrial tachycardia Atrial fibrillation Atrial flutter Supraventricular tachycardia AV nodal re-entrant (60%) Atrioventricular reentry, accessory pathway (30%) Initial evaluation Vital Signs: stable vs. unstable History & Physical Exam EKG Other diagnostic modalities Stable vs. Unstable The urgency of therapy depends on hemodynamic stability. If unstable… address ABC’s first and brady: call for external pacers and wide QRS: call for defibrillator All patients: Consider underlying ischemia or heart failure Telemetry and pulse oximetry Stable vs. Unstable The hemodynamic impact of an arrhythmia depends on: the ventricular response preservation of cardiac output degree of underlying structural or ischemic disease History Family or personal history of arrhythmia, ischemic disease, valvular disease Assess recent medications ROS: Chest pain, SOB, palpitations, presyncope, syncope Above may occur w/ any arrhythmia Physical Exam Airway Oxygenation Pulses, IVs Mentation Regular or irregular? Murmur? Crackles? JVD? Look at the monitor. Supraventricular arrhythmia: Rapid, narrow QRS complex (<120 msec) with P waves IF SVA: attempt vagal maneuvers Breath-holding or Valsalva Carotid massage Diagnosis Progress from simple to invasive testing. EKG is the first line in diagnosis. Early in evaluation , address underlying abnormalities which may be triggers: Ischemia (EKG) Hypercarbia (ABG) Proarrhythmic drugs Electrolytes (BMP) Malpositioned catheter (CXR) Electrocardiogram Conduction velocity Through AV Node EKG and Supraventricular Arrhythmia Assess QRS: wide vs. narrow Wide: ventricular arrhythmia, but also SVA w/ bundle block or accessory pathway Look for presence of P waves No p waves- suspect A fib. Rate 300 bpm suggests atrial flutter More P waves than QRS: AV block SA node firing but signal not conducting Other diagnostic modalities ECHO Evaluates for functional and structural abnormalities Electrolytes Thyroid function tests EP Studies: Supraventricular arrhythmias Atrial tachycardia Atrial fibrillation Atrial flutter SVT AV nodal re-entrant (60%) Atrioventricular reentry, accessory pathway (30%) SVA: Atrial Fibrillation MC post-op arrhythmia Impulse above bundle of His -> disorganized atrial activity, dyssynchrony of contraction between atrium and ventricle Loss of atrial kick and reduced CO No reserve = unstable Stasis leads to thromboembolic events Afib: Risk Factors Patient Factors Surgeries with high risk AF Age >60 years old** Esophagectomy Male gender Pulmonary resection CHF Intra-abdominal surgery Valvular disease Vascular surgery Prospective database 2588 pts undergoing major non-cardiac thoracic surgery at a single institution, 1998 to 2002 What are the risk factors associated with atrial fibrillation after noncardiac thoracic surgery? J Thorac Cardiovasc Surg 2004; 127:779-86). J Thorac Cardiovasc Surg 2004; 127:779-86). Results: rate of a fib= 12.3% development a fib significantly increased mortality rates (from 2.0% to 7.5%), length of stay, and cost of stay Prospective Observational n= 460pts AF in 5.3% Crit Care Med 2004; 32:722–726) Atrial Fibrillation: Treatment Who to treat? Pts with heart failure Afib >48h Uncontrolled ventricular rates Prior history of stroke How to treat? Rate control Slows HR and allows ventricular filling Rhythm control Resynchronizes to NSR Anticoagulation? Afib: Treatment Rate control Slows ventricular response, allows ventricular and coronary filling, increased CO Treatment options: Beta-blockers Calcium Channel Blockers Amiodarone Digoxin Afib: Rate control Beta-blockers 1st line for rate control Direct anti-arrhythmic activity on conduction cells Counteract hyperadrenergic post-op state Shown to accelerate conversion to sinus rhythm vs. CCBs Agents: Esmolol, Metoprolol Contraindications: Hypotension, bradycardia, heart block, decompensated heart failure, asthma Afib: Rate control Calcium Channel Blockers (CCBs) 2nd -line therapy for rate control, or 1st line for those intolerant of B-Bl Block the calcium channel in AV node, leads to slower impulse conduction Agents: Verapamil, diltiazem May result in hypotension Afib: Rate control Amiodarone Digoxin Good choice for heart Increases parasympathetic failure, HD instability Monitor for ADRs: stimulation to heart Good choice in heart failure Sinus brady AV block Respiratory dysfunction hypotension Afib: Rhythm control Re-synchronizes atrium with ventricle Pharmacologic or electrical (DC) Afib: Rhythm control Pharmacological: Single dose flecanide or propafenone Risk of VT, sinus brady; contraindicated in CAD Prolongs QT Ibutilide Use in unstable hemodynamics, adr: nausea Prolongs QT, don’t use in hypokalemia Amiodarone Good choice in heart failure, structural heart dz ADR: thyroid, optic, pulm toxicity Afib: Rhythm control Electrical: Direct Current cardioversion Use for: ongoing stable Afib >48h refractory Afib, unstable/ischemic Don’t use: asymptomatic arrhythmia 120- 200 joule biphasic or 200 joule monophasic shock in synchrony w QRS complex Exclude intracardiac thrombus w/ TEE Maintain w amiodarone, sotalol Afib: Rhythm control Prospective study Primary success rate of DC cardioversion in postop ICU pts w new-onset supraventricular tachyarrhythmias N= 37 pts NSR restored in 35% after 1 shock, with 100% converted after 4 shocks At 48 hours, only 13.5% remained in sinus rhythm ?different pathophysiologic mechanisms in surgical pts, making them less responsive to DC cardioversion Crit Care Med 2003; 31:401-405 Multicenter RCT 4060 pts w Afib: rate control vs. rhythm control Primary endpoint: mortality Inclusion age>65 At least 1 risk factor for stroke or death (LA enlargement, HTN, DM, CHF, prior TIA, LV dysfunction) Results: rhythm control offers no mortality benefit over rate control Potential benefits in rate control in less toxic drugs Systematic review, 1966- 2006 4 trials, 143 pts w/ supraventricular arrhythmia Crit Care Med 2008; 36:1620–1624 “Using published literature, we cannot recommend a standard treatment for atrial fibrillation in non-cardiac ICU patients” Crit Care Med 2008; 36:1620–1624 Atrial Fibrillation: Anticoagulation When to anticoagulate? J Am Coll Cardiology, 2014; 64: 2246-80 Nonvalvular: CHA2DS2-VaSc Anticoag for CHADS 2 or higher, prior stroke Bridge depending on risk:benefit Valvular: warfarin, bridge prn CHEST 2010; 137(2):263–272 SVA: Atrial Flutter (AF) Reentrant arrhythmia Alternate circuit rotates around tricuspid valve annulus Saw-tooth pattern of P waves Usual rate 240-320 bpm A rate of 150 bpm could be AF with 2:1 AV block SVA: Atrial Flutter Rate control Diltiazem, verapamil, beta-blockade Digoxin for CHF Rhythm control Ibutilide, dofetilide, sotalol to terminate rhythm May prolong QT and lead to torsades DC cardioversion: 50- 100 joule biphasic shock If recurrent: EP for ablation Supraventricular Tachycardia Narrow complex <120 msec P wave may be buried in QRS May see wide QRS if present with BBB or accessory pathway Sudden onset and termination Common subtypes include: AV nodal reentrant AV reciprocating Focal atrial tachycardia SVT: treatment Vagal maneuvers Carotid massage, Valsalva Stimulate baroreceptors, increase vagal activity, slows impulse conduction through AV node SVT: treatment Pharmacotherapy Adenosine AV nodal blocking agent, t1/2= 10 seconds 1st line tx SVT Diagnostic and tx for wide-complex SVT RCTs: 60-80% termination with 6mg adenosine, 9095% after 12mg. Use under cardiac monitoring with defibrillation pads in place (asystole or VF may result) Don’t use in heart transplant SVT: treatment Pharmacotherapy Verapamil or diltiazem Use for recurrent SVT after adenosine May cause vasodilation, bradycardia, heart block Esmolol Short half-life Preferred for use in pts at risk for B-bl complications Multicenter, retrospective, observational study 197 pts w wide-complex tachycardias Response to adenosine: 90% with SVT and 2% with v-tach No adverse events in either groups Response to adenosine increased odds of SVT by 36x, and nonresponse increased odds of ventricular tachycardia by 9x Adenosine is safe in wide-complex tachycardia as both diagnostic and therapeutic measure Crit Care Med 2009; 37:2512-2518. SVT: treatment If SVT still refractory to above therapies: Antiarrhythmics (watch for torsades) Procainamide Ibutilide For unstable SVT: R-wave synchronous DC cardioversion with 100- 200 joules Objectives: Review anatomy and physiology of cardiac conduction system. Define supraventricular arrhythmia. Describe the initial approach to a patient with an arrhythmia. Discuss diagnosis and treatment options for patients with atrial fibrillation, atrial flutter, and supraventricular tachycardia. SUMMARY Supraventricular arrhythmia : any arrhythmia initiated above the atrioventricular node Afib, a flutter, SVT Stable vs. Unstable… if unstable, ABCs, consider cardioversion If stable, obtain a 12 lead ECG… A Fib, A Flutter: rate vs. rhythm control SVT: vagal maneuvers, adenosine Remember risk factors and precipitating conditions in surgical pts Long term therapy depends on mechanism and can be conservative, pharmacologic or invasive Bibliography AHA/ACC task force members. “Guideline for the Management of Patients with Atrial Fibrillation.” J Am Coll Cardiol 2014; 64: 2246-80. Delacretaz, E. “Supraventricular Tachycardia.” N Engl J Med, 2006; 354:1039-51. Halonen J, Halonen P, Jarvinen O, et al: Corticosteroids for the prevention of atrial fibrillation after cardiac surgery: A randomized controlled trial. JAMA. 2007; 297: 1562–1567 Kanji S, Stewart R, Ferguson D, et al: Treatment of new-onset atrial fibrillation in noncardiac ICU patients: A systematic review of randomized controlled trials. Crit Care Med 2008; 36:1620–1624 Lip et al. “Refining clinical risk stratification for predicting stroke and thromboembolism in atrial fibrillation using a novel risk factor-based approach.” CHEST 2010; 137(2): 263-272. Marill, K. et al. “Adenosine for wide-complex tachycardia: Efficacy and safety.” Crit Care Med 2009; 37: 2512-2518. Bibliography Mayr, A. et al. “Effectiveness of direct-current cardioversion for treatment of supraventricular tachyarrhythmias, in particular atrial fibrillation, in surgical intensive care patients.” Crit Care Med 2003; 31: 401- 405. Seguin, P. et al. “Incidence and risk factors of atrial fibrillation in a surgical intensive care unit.” Crit Care Med 2004; 32: 722-726. Vaporciyan, A. et al. “Risk factors associated with atrial fibrillation after noncardiac thoracic surgery.” J Thorac Cardiovasc Surg 2004; 127: 779-86. Wyse et al. “A Comparison of rate control and rhythm control in patients with atrial fibrillation.” N Engl J Med, 2002; 347: 1825-33.