Association of New Left Anterior Fascicular Block with Structural Heart Disease in U.S. Air Force Military Aircrew Talib Y. Ali, MD, MPH Lt Col, USAF, MC, FS USAF School of Aerospace Medicine WPAFB, OH RAM 2013 Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW-2013-2294, 13 May 2013 1
Disclosure Information 84th Annual Scientific Meeting Dr. Talib Y. Ali I have no financial relationships to disclose. I will not discuss off-label use and/or investigational use in my presentation. Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW-2013-2294, 13 May 2013 2
Introduction Left anterior fascicular block (LAFB) may be a marker of underlying structural heart disease Coronary artery disease LAD coronary artery Arterial hypertension Aortic heart disease Certain cardiomyopathies Varies in prevalence from 0.9% to 6.2% in the general population 1 and 0.01% to 0.9% in the military aviator 2,3 Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW-2013-2294, 13 May 2013 3
Introduction Military aircrew are healthier than the general population Current USAF policy requires further evaluation in aircrew with LAFB 4 Age > 35 years Exercise treadmill testing and echocardiogram Age 35 years Echocardiogram Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW-2013-2294, 13 May 2013 4
Introduction 1.2 million ECGs in the USAF School of Aerospace Medicine (USAFSAM) ECG Library dating back to 1950 281,737 unique aviators (current as April 2013) Expand upon research by Yoosefian, Lopez, and Kruyer 5 Review LAFB evaluation results to assess the usefulness of the current USAF policy Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW-2013-2294, 13 May 2013 5
Methods LAFB Displacement of the mean QRS axis in the frontal plane to between -45 and -90, and A qr complex in leads I and AVL, an rs complex in leads II, III and AVF, and Normal or only slightly prolonged QRS duration Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW-2013-2294, 13 May 2013 6
Methods Reviewed the records of 702 unique military aircrew with new LAFB contained in the USAFSAM ECG Library with demographics (BP, Age, Ht, Wt) Testing data available limited to diagnostics performed at USAFSAM only Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW-2013-2294, 13 May 2013 7
Methods Echocardiogram classification Normal Normal Variant Abnormal Exercise treadmill testing classification Normal Borderline Abnormal Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW-2013-2294, 13 May 2013 8
Demographics (561 unique aircrew) Average Age: 36 yr (19 to 63 yr) Average Height: 71" (62 to 79") Average Weight: 180 lb (114 to 260 lb) BMI 25.1 Results Demographics (359 unique aircrew) Average BP: 121/77 mmhg Systolic 96 to 172 mmhg Diastolic 60 to 116 mmhg Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW-2013-2294, 13 May 2013 9
Results 41 underwent echocardiography 7 (17%) were interpreted as Normal 23 (56%) were interpreted as Normal Variant 11 (27%) were interpreted as Abnormal 56 underwent exercise treadmill testing 52 (93%) were interpreted as Normal 1 (2%) were interpreted as Borderline 3 (5%) were interpreted as Abnormal Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW-2013-2294, 13 May 2013 10
Results 11 (27%) with Abnormal Echocardiography 2 - Bicuspid AV 2 - Mild LAE 2 Septal motion abnormalities 1 Mild RV hypertrophy 1 - Mild AI 1 AV thickening 1 MVP 1 Mild PI Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW-2013-2294, 13 May 2013 11
3 (5%) with Abnormal Exercise Treadmill Testing 1 with ST Segment Depression 1 with LBBB/AV Block Results 1 with PVCs and Ventricular Tachycardia Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW-2013-2294, 13 May 2013 12
Results Transient LAFB 31 aviators - NSR LAFB 9 aviators - NSR LAFB NSR 4 aviators - NSR LAFB NSR LAFB 4 aviators - LAFB NSR 4 aviators - LAFB NSR LAFB LAFB Prevalence = 0.249% (702/281737) Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW-2013-2294, 13 May 2013 13
Conclusion Inconclusive if isolated LAFB in USAF aircrew appears to be predictive of underlying heart disease Stress testing is likely warranted over age 35 in the setting of LAFB Echocardiography is likely warranted in the setting of LAFB ECG Library has limitations, particularly if studies performed locally Further investigation required Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW-2013-2294, 13 May 2013 14
References 1. Elizari MV, Acunzo RS. Hemiblocks Revisited. Circulation. 2007;115(8):1154-63. 2. Hiss RG, Lamb LE. Electrocardiographic findings in 122,043 individuals. Circulation. 1962;25(6):947-961. 3. Rotman M, Triebwasser JH. A clinical and follow up study of right and left bundle branch block. Circulation. 1975;51(3):477-484. 4. Yoosefian F, Lopez FM, Kruyer W. Association of new left anterior or posterior fascicular block with structural heart disease in military aircrew. Aviat Space Environ Med 2010;81(3):291. 5. US Air Force Aeromedical Consultation Service Central Electrocardiographic Library. Disposition of ECG findings in USAF Aircrew. Oct 2009:4. Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW-2013-2294, 13 May 2013 15
Questions? Distribution A: Approved for public release; distribution is unlimited. Case Number: 88ABW-2013-2294, 13 May 2013 16