A major teaching hospital of Harvard Medical School Role of Echocardiography in Atrial Fibrillation Kyle K. Pond December 15th, 2004

A major teaching hospital of Harvard Medical School Outline 1. Prevalence and epidemiology of atrial fibrillation 2. Use of transthoracic echocardiography -chamber sizes and function -valvular function 3. Use of transesophaeal echocardiography -detection of atrial thrombi -detection of other high risk factors -role timing of cardioversion -assessment of return of atrial mechanical function

A major teaching hospital of Harvard Medical School Atrial Fibrillation Common arrhythmia -estimated 2.3 million adults in US -approaching 200,000 hospital admissions/yr Disease of the elderly -4% of the population over the age of 60 -5/122,000 healthy Air Force recruits found to have atrial fibrillation on screening EKG (Hiss et al Circulation 1962) 20-26/100,000 deaths in Massachusetts in 1999 listed AF as contributing cause

A major teaching hospital of Harvard Medical School Epidemiology (cont) Atrial Fibrillation is BAD -Data from the FHS suggests that chronic AF confers an almost 2X increase in both overall and cardiovascular mortality (women>men). (Vaziri et al, Circ 1994).

My algorithm for treating atrial fibrillation A major teaching hospital of Harvard Medical School My algorithm for treating atrial fibrillation

A major teaching hospital of Harvard Medical School Potential Clinical Consequences 1. Thromboembolism 2. Tachycardia mediated cardiomyopathy 3. Hemodynamic deterioration 4. Symptoms

A major teaching hospital of Harvard Medical School

A major teaching hospital of Harvard Medical School Role of TTE in atrial fibrillation -Provides useful/prognostic information about cardiac anatomy, structure, and function

A major teaching hospital of Harvard Medical School Left Atrium -normal is <4.0cm -size of left atrium is important in helping to determine prognosis -increased size decreases the probability of maintaining sinus rhythm -increased LA size among the strongest predictors of development of new AF (HR 1.39 in previously mentioned FHS paper) -chronic AF, rheumatic MV dz, and severe LA enlargement (>6cm) have highest risk of recurrence (9) -ACC/AHA guidelines for anticoagulation in severe rheumatic MS in absence of AF-> LA size > 5.5 cm

A major teaching hospital of Harvard Medical School (cont) -LA size increases with progressive duration of AF -suggests AF “promotes” LAE -DCCV and maintenance of sinus rhythm are thought to possibly reverse LAE

A major teaching hospital of Harvard Medical School

A major teaching hospital of Harvard Medical School Summary -Evaluation of the LA size provides important prognostic information -ability to maintain sinus rhythm -likelihood of recurrence of AF or initial development of AF in someone without a prior hx -presence of significant LAE should not be an exclusion criteria for CV

A major teaching hospital of Harvard Medical School Left Ventricle -LVH, focal WMA, AS, pericarditis, or other causes of AF -LV dysfunction independently predicts stroke risk -based on meta-analysis of 1066 patients -in control groups-incidence of CVA -9.3%/yr in patients with mod/severe LV dysfxn -4.4%/yr in patients with no/mild LV dysfxn

A major teaching hospital of Harvard Medical School

A major teaching hospital of Harvard Medical School Mitral Valve TTE evaluates the degree of mitral valve disease -Gives prognostic information -Pts can initially present in afib,->can detect mitral stenosis -can affect duration of tx

A major teaching hospital of Harvard Medical School Mitral Regurgitation -evaluated by TTE -? protective against atrial fibrillation due to minimization of stasis in the LA and appendage Goldsmith et al, AJC 2000)

A major teaching hospital of Harvard Medical School TTE can help risk-stratify patients with atrial fibrillation -specifically low risk clinical patients may be at increased risk when TTE performed -SPAF data -low clinical, low echocardiographic risk (<1%/yr CVA) -low clinical, high echocardiographic risk (>5%/yr CVA)

A major teaching hospital of Harvard Medical School Bottom line: “The routine performance of transthoracic echocardiography is suggested for all patients presenting with their first episode of AF to obtain information regarding cardiac structure and function.” -WJM “UpToDate--2/04”

A major teaching hospital of Harvard Medical School

A major teaching hospital of Harvard Medical School Left Atrial Thrombi -In general poorly visualized by TTE (39-63% sensitive) -lower in LAA (<20% visualization of LAA on TTE). -TEE much better ->200 patients prior to MV repair/replacement -56% with H/O afib -sensitivity/specificity for left atrial thrombi were 100%/99% as compared with direct surgical visualization (Manning WJ et al, Arch Int Med 1995)

A major teaching hospital of Harvard Medical School LA thrombi in AF -seen in 10-15% of pts. with >72 hours of AF --much higher in pts with higher risk features --more likely if any of the following are visualized -dense LA smoke -low LAA velocity (usually <20cm/sec) -complex aortic plaque (SPAF-III TEE substudy)

A major teaching hospital of Harvard Medical School

A major teaching hospital of Harvard Medical School

A major teaching hospital of Harvard Medical School

A major teaching hospital of Harvard Medical School TEE for identifing LA thrombus in AF -facilitated early cardioversion -in patients with acute thromboembolism (TE) ->40% of patients with acute TE and newly recognized AF were found to have LA thrombus -Routine TEE in this population is controversial at best

A major teaching hospital of Harvard Medical School TEE for facilitated early cardioversion -cardioversion->improves symptoms, cardiac function, ? decrease the risk of thrombus formation -DCCV without antecedent anticoagulation -approx 6% incidence of clinical TE

A major teaching hospital of Harvard Medical School Transesophageal Echocardiographically Facilitated Early Cardioversion From Atrial Fibrillation Using Short-Term Anticoagulation (Manning WJ et al, JACC 1995) -230 consecutive patients with atrial fibrillation >2 days or unknown duration -all underwent TEE-identifying 40 atrial thrombi in 34 patients (15%). -186/196 (95%) without thrombi had successful DCCV to NSR—none had a thromboembolic event Bottom Line-1st large scale study to show that TEE facilitated early cardioversion with short-term anticoagulation is safe and effective.

A major teaching hospital of Harvard Medical School AF of <48 hours duration -appears to be little role for TEE -375 patients with AF < 48 hours duration; no TEE -conversion to NSR in 95% -clinical thromboembolic event in 3 (0.8%) -similar to rate when on coumadin X 4 weeks

A major teaching hospital of Harvard Medical School Left Atrial Appendage Function - blood flow velocity is a quantifiable measure of stasis - low velocity associated with higher risk of thrombus formation - also associated with dense spontaneous echo contrast - low blood flow velocity (<15mm/sec) associated with increased risk of CVA (Shivelly BK, et al JACC 1996; 27:1772)

A major teaching hospital of Harvard Medical School Velocity predicts long term maintenance of sinus rhythm in pts with nonvalvular AF (Antonielle E, JACC 2002:39) -186 pts eventually successfully cardioverted to NSR. All had AF>48 hours. -TEE/TTE/clinical parameters obtained -at one year F/U 91/186 patients were in NSR

A major teaching hospital of Harvard Medical School

wave and appendage filling following the QRS. A major teaching hospital of Harvard Medical School Normal Doppler flow pattern in the left atrial appendage. There is appendage emptying following the P wave and appendage filling following the QRS.

A major teaching hospital of Harvard Medical School

A major teaching hospital of Harvard Medical School Spontaneous Echo Contrast -can be seen on TTE or more commonly TEE -“likely due to blood stasis in a cavity or related to alterations in blood components such as RBCs, fibrinogen, or platelets” (Manning WJ in Otto). -Fc receptor on platelet binding to fibrinogen -spontaneous contrast increases likelihood of LAA clot (Black et al JACC 1991) -spontaneous contrast increases likelihood of CVA (Chimowitz MI et al 1993) -not a “treatable” finding->marker for increased risk -coumadin and ASA have no effect on smoke -does reduce risk of CVA

A major teaching hospital of Harvard Medical School Is the presence of spontaneous echo contrast in the absence of LAA thrombus a contraindication (relative or otherwise) for subsequent DCCV?

A major teaching hospital of Harvard Medical School

A major teaching hospital of Harvard Medical School Return of Atrial Mechanical Function -Pulsed doppler transmitral echo can assess LA function -DCCV of AF of short duration leads to earlier return of atrial fxn -Longer duration AF takes longer for atrial function to recover -Led to recommendation of longer term anticoagulation post-DCCV -clinical utility unclear

A major teaching hospital of Harvard Medical School

A major teaching hospital of Harvard Medical School Other controversies/future questions 1. TEE before DCCV in patients with prior TEE evidence of thrombus and then subsequent adequate anticoagulation 2. Better why to risk stratify patients to ASA or coumadin based on TEE findings 3. Is DCCV worse for the LA than pharmacologic cardioversion?

A major teaching hospital of Harvard Medical School