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CRITICAL CARE CARDIOLOGY ISSUES ARRYTHMIAS. Yatish B. Merchant, MD, FACC Cardiology, New Jersey USA. Perioperative arrythmias. Q. Commonest arrythmia seen PAT Atrial Flutter Atrial fibrillation Ventricular tachycardia. Atrial Fibrillation. Most common arrythmia seen post op.
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CRITICAL CARE CARDIOLOGY ISSUESARRYTHMIAS Yatish B. Merchant, MD, FACC Cardiology, New Jersey USA
Perioperative arrythmias • Q. Commonest arrythmia seen • PAT • Atrial Flutter • Atrial fibrillation • Ventricular tachycardia
Atrial Fibrillation • Most common arrythmia seen post op. • Incidence 20 to 50 % after open-heart surgery. • Increased morbidity & prolonged ICU stay & hospitalization with increased cost
Patterns of Atrial Fibrillation First detected >7 days <7 days May be recurrent Paroxysmal (self-terminating) Persistent (not self-terminating) Cardioversion failed or not attempted Cardioversion failed or not attempted Permanent (accepted) Fuster V, et al. J Am Coll Cardiol 2006;48:854.
Atrial Fibrillation • Post op AF is multifactorial. • Many predictors have been identified.
Atrial Fibrillation Predictors • Age (>65 yrs) • Sex (male) • High BMI • Hypertension (LVH) • COPD • Hypoxia • Atrial ischemia • P wave duration • Atrial pacing • Net fluid balance • Reduced LV EF (CHF) • Mg level • Amiodarone prophylaxis • Use of B-Blocker • Post op catecholamine use • Duration of C-P bypass • Off pump surgery • Duration of cross clamp
Stress State Inflammatory State Hypoxic State • Surgical Trauma • Anesthesia/analgesia • Intubation/extubation • Pain • Hypothermia • Bleeding/anemia • Fasting Triggers • Anesthesia/analgesia • Hypothermia • Bleeding/anemia • Surgical Trauma • Anesthesia/analgesia ↑TNF-α ↑IL-1 ↑IL-6 ↑CRP ↓oxygen delivery ↑ catecholamine and cortisol levels ↑ BP ↑ HR ↑ FFAs ↑ relative insulin deficiency ↑ Oxygen demand Atrial Fibrillation
Atrial Fibrillation • Statins for prevention of AF after Cardiac surgery (anti-inflammatory effect). Oliver J Liakopoulos,: The Journal of Thoracic and Cardiovascular Surgery Sept 2009
Atrial Fibrillation • Literature search : Influence of preop statin therapy on the incidence of post op AF • Total 17,643 pts having heart surgery. • 58.4 % with preop. statin Rx • 41.6 % without Oliver J Liakopoulos,: The Journal of Thoracic and Cardiovascular Surgery Sept 2009
Atrial Fibrillation • Total AF incidence 24.6 % • Pre op statin group 22.3 % • Without 27.8 % (P<0.001) • Absolute reduction 5.5% • Relative risk reduction 19.9 % Oliver J Liakopoulos,: The Journal of Thoracic and Cardiovascular Surgery Sept 2009
Atrial Fibrillation • AF is associated with increase long term risk of stroke , all cause mortality, especially in women • Mortality rate of AF patients is 2X that of patients in NSR with similar heart disease • In the Framingham study, the annual risk of stroke secondary to AF was 1.5% in participants 50 to 59 Y old and 23.5% in those aged 80 to 89 Y
Autonomic Influences in A fib • Vagal A-Fib: secondary to increased parasympathetic tone is the more common form. (Adrenergic blockers or digitalis sometimes worsen symptoms). • Adrenergic A- Fib: beta-blockers are initial treatment of choice. • Digitalis is more effective in controlling HR at rest in AF but less effective during activity • .
Hemodynamic consequences of A Fib • Loss of atrial contraction • Variation of R-R intervals • Decrease coronary blood flow • Increase coronary vascular resistance • Increase mean LA volume • Tachycardia induced Ventricular cardiomyopathy
ANTITHROMBOTIC THERAPY AFib Management Treatment Options VENTRICULAR RATE CONTROL Pharmacologic Nonpharmacologic ACHIEVEMENT AND MAINTENANCE OF SINUS RHYTHM Pharmacologic Nonpharmacologic
Rhythm vs Rate Control Trials: AFFIRM • Randomized, multicenter trial with 4060 patients • Elderly (mean age 69.7 years) • 71% HTN, 65% enlarged LA, 38% CAD, 26% reduced LVEF • 90% AFib within 6 weeks of trial, 69% AFib duration >2 days; 35% first episode • Treatments compared were heart rate control (BB, CCBs, digoxin) vs sinus rhythm control (cardioversion and AADs) • Initial warfarin anticoagulation in both groups • Mean follow-up 3.5 years The AFFIRM Investigators. N Engl J Med. 2002;347:1825-1833.
Primary Endpoint of All-Cause Mortality: AFFIRM 30 Rate (n=2027) 25 Rhythm (n=2033) 20 P= .08 unadjusted P= .07 adjusted 15 Cumulative Mortality, % 10 5 0 3 2 5 0 1 4 Time (years) No. Deaths Rhythm: 0 80 175 257 314 352 Rate: 0 78 148 210 275 306 The AFFIRM Investigators. N Engl J Med. 2002;347:1825-1833.
When do you decide to give Warfarin? • A – Fib for • >7 days • >4 days • >2 days • >1 day.
Nonvalvular Atrial Fibrillation Stroke Rates Without Anticoagulation According to Isolated Risk Factors Stroke Rate (%/year) Heart Failure LVEF Female Diabetes Prior Stroke/TIA Hypertension Age > 75 years Hart RG et al. Neurology 2007; 69: 546.
The CHADS2 IndexStroke Risk Score for Atrial Fibrillation Score Points • Congestive Heart Failure 1 • Hypertension 1 • Age > 75 yrs 1 • Diabetes 1 • Stroke (Previous TIA/CVA) 2
The CHADS2 Index Stroke Risk Score for Atrial Fibrillation Score (points) Risk of Stroke (%/year) 01.9 1 2.8 2 4.0 3 5.9 4 8.5 5 12.5 6 18.2 Van Walraven C, et al. Arch Intern Med 2003; 163:936. Go A, et al. JAMA 2003; 290: 2685. Gage BF, et al. Circulation 2004; 110: 2287.
The CHADS2 Index Stroke Risk Score for Atrial Fibrillation Score (points) Risk of Stroke (%/year) 01.9 1 2.8 2 4.0 3 5.9 4 8.5 5 12.5 6 18.2 Approximate Risk threshold for Anticoagulation 3%/year Van Walraven C, et al. Arch Intern Med 2003; 163:936. Go A, et al. JAMA 2003; 290: 2685. Gage BF, et al. Circulation 2004; 110: 2287.
Atrial Fibrillation • Current guidelines : Anticoagulation if A-Fib > 48 hrs. • Post op Thromboembolism occurs in <12 hrs • Case report of AF 9 days after CABG converted to sinus with amio & lopressor without anticoagulation in 12 hrs had CVA. • TEE showed clot in LAA with normal. • Dr David Verhaert, Cleveland clinic, ohio • Cleveland clinic, ohio
INR at the Time of Stroke or BleedingEfficacy and Safety of Warfarin 20 15 Ischemic Stroke Intracranial bleeding Odds Ratio 10 5 1 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 International Normalized Ratio Fang MC, et al. Ann Intern Med 2004; 141:745. Hylek EM, et al. N Engl J Med 1996; 335:540.
Warfarin for Atrial FibrillationLimitations Lead to Inadequate Treatment Adequacy of Anticoagulation inPatients with AF in Primary Care Practice INR above target6% No warfarin65% INR intarget range15% Subtherapeutic INR 13% Samsa GP, et al. Arch Intern Med 2000;160:967.
Rhythm Control for AFib:Commonly Used Oral Antiarrhythmic Drugs Class IA Class IC Class III Quinidine Procainamide* Disopyramide* Propafenone** Propafenone SR** Flecainide** Sotalol Amiodarone* Dofetilide *Procainamide, disopyramide, and amiodarone are not FDA-approved for treatment of AFib. **Only propafenone, propafenone SR, and flecainide are FDA-approved for out-patient initiation. Miller JM, Zipes DP. In: Zipes DP, et al, eds. Braunwald’s Heart Disease. 2005.
Antiarrhythmic Drug Selection Guidelines* for Sinus Rhythm Control in Patients with AFib Heart Disease No (or minimal) Yes HF CAD Hypertension Flecainide Propafenone Sotalol Amiodarone Dofetilide Dofetilide Sotalol Substantial LVH Amiodarone Yes No Amiodarone, Dofetilide Catheter Ablation Flecainide Propafenone Sotalol Amiodarone Amiodarone Dofetilide ACC/AHA/ESC Practice Guidelines, JACC Vol. 48 No. 4, Aug 2006. Catheter Ablation
Atrial Fibrillation • Lymphatic system of the heart • (1) Subendocardial, Myocardial & epicardial plexuses. • (2) Drainage of conduction tissue • (3)Main or principle lymphatic trunks (PLT) • 1 & 2 drain in to 3 then to mediastinal LN to thoracic duct to blood stream. Ryszard W. Lupinski : ANZ J Surgery 2009
Atrial Fibrillation • Role of lymphatics is to protect the interstitial space against tissue swelling, removal of debris from injured tissue. • Disruption >> Lymphostasis>>Interstitial pressure rises>> swelling. • ECG changes similar to coronary event.
Atrial Fibrillation • Regeneration & integrity of lymphatic vessels takes 2-20 wks depending on the damage.
Atrial Fibrillation • Studies have shown patients with post op A- Fib have higher heart rate & more frequent PAC’s. • Autonomic nervous system imbalance is one of the major factor for post op A-Fib. • Dr Melo: Journal of thoracic and cardiovascular surgery 2004
Atrial Fibrillation • Ventral cardiac denervation procedure with CABG. • Dr Melo: Journal of thoracic and cardiovascular surgery 2004
Atrial Fibrillation • Total 110 pts. (58 & 52) • Occurrence of AF was 7 % in Rx group & 27 % in control group (P < 0.001 ) • All 7% pts AF was less severe & cardioverted with medicines alone. • None of them had readmission for AF after discharge • Dr Melo: Journal of thoracic and cardiovascular surgery 2004
Atrial Fibrillation • Age : < 70 yrs + cardiac denervation procedure = Reduction in AF incidence • > 70 yrs No significant benefit • Same number of nerves but have less axons per nerve.
Atrial Fibrillation • Off-pump CABG reduces the incidence of A-Fib. • Less invasive • Less marked periop inflammatory response • No cross clamp. No lymphatic interruption • Dr Hosokawa British journal of anesthesia : feb 2, 2007
Atrial Fibrillation • What are the Predictors of AF after off-pump CABG • Dr Hosokawa British journal of anesthesia : feb 2, 2007
Atrial Fibrillation • 296 pts : • 32% developed AF • Most freq. on day 2. • Dr Hosokawa British journal of anesthesia : feb 2, 2007
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Atrial Fibrillation Advanced age : age related degenerative changes seen as P wave duration & PR interval Hypovolaemia Low cardiac output Higher intraoperative core temperature • Dr Hosokawa British journal of anesthesia : feb 2, 2007
Atrial Fibrillation • Does Minimal-Access AVR, compared to conventional AVR, reduce the incidence of Post-Op AF? Bari Murtuza : Tex Heart Institute J 2008
Atrial Fibrillation Bari Murtuza : Tex Heart Institute J 2008
Atrial Fibrillation • No difference in incidence of Post-op AF • Benefit : 1) Fewer respiratory complication and less blood transfusion required. 2) Cosmetically better. • Disadvantage: 1) Longer CPB time, Longer aortic cross clamp time. 2) More cost. 3) Increased incidence of pleural & pericardial effusions. Bari Murtuza : Tex Heart Institute J 2008