ELECTROPHYSIOLOGY per minute and the atria and ventricles are not coordinating well , impairing the ability of the heart muscle to adequately supply blood to the brain and the rest of the body as a result of the rapid rate and weak contractions . VT is seen most commonly in patients with a weakened heart muscle from cardiomyopathy or from scar tissue as a result of a prior heart attack . Sudden cardiac death causes more than 450,000 mortalities each year in the U . S ., and most commonly caused by VT evolving into ventricular fibrillation ( VF ). VF can be fatal if not defibrillated into normal rhythm .
To perform the procedure , skilled electrophysiologists on the medical staff place a long , thin wire into the heart chambers femorally ( through veins in the leg ). Once the areas of the arrhythmia are identified , a localized burst of radiofrequency energy is applied , cauterizing the abnormal electric circuit of the VT .
Of particular note for VT ablation , the availability within the EP lab of sophisticated 3-D mapping technology decreases the need for fluoroscopy and improves efficiency for procedural time . The arrhythmia-locating technology combines magnetic and current-based technologies for real time display of the catheter locations , as well as intra-cardiac echocardiography images of the heart ’ s chambers . These maps contain anatomical , electrical voltage , electrical activation times , and ablation data .
Prior to the ablation , standard protocols include ordering special cardiac imaging with CT and / or echocardiography . A transesophageal echocardiogram may be performed to exclude the presence of blood clots in the heart and assess the pumping ability of the heart . Now , with the presence of the MRI in the Advanced Imaging Department at Baylor Scott & White Heart and Vascular Hospital - Dallas , patients with an ICD and under supervision , may be sent for cardiac MRI where the heart ’ s pumping ability can be readily identified in action .
Left Atrial Appendage Occlusions ( LAAO )*
* Baylor Scott & White Heart and Vascular Hospital - Dallas ( FY18 )
26
Left Atrial Appendage Occlusion ( LAAO )
A-Fib can decrease the heart ’ s pumping efficiency by as much as 30 percent . Poor pumping increases the risk of clots forming in the heart chambers , particularly the left atrial appendage ( LAA ). The LAA is pouch-shaped and about the size of your thumb . It is located on the top of the heart .
LAA occlusion generally eliminates the risk of stroke without the need for blood thinners . Electrophysiologists on the medical staff have been successful with bringing the WATCHMAN™ device through clinical trials and post FDA approval . Approved by the FDA in 2016 after years of research and clinical trials proving its effectiveness , this LAAO device is now a more commonly offered viable option for many patients .
The LAAO device is designed to prevent blood clots that frequently form in the LAA from traveling in the blood stream to the brain , lungs and other parts of the body . Clots that travel to the brain cause strokes , one of the leading causes of death and disability .
The interventional cardiologist uses fluoroscopic imaging to guide a sheath into the left atrial appendage . The sheath serves as a duct for the delivery of a catheter that is pre-loaded with the device , which is parachute-shaped and the size of a quarter . The device consists of a nitinol cage with a polytetrafluoroethylene membrane and includes a row of fixation barbs . With this device , patients are generally released from the hospital after 24 hours . Medical follow-up continues over the course of time as patients decrease their blood thinner medication under the supervision of a cardiologist .
LAAO device is suitable for patients with nonvalvular atrial fibrillation who :
• Are at increased risk for stroke and systemic embolism based on CHADS2 or CHADS2-VASc scores and are recommended for anticoagulation therapy
• Have an appropriate rationale to seek a non-pharmacologic alternative to oral anticoagulation , taking into account the safety and effectiveness of the device compared to warfarin
WATCHMAN™ image courtesy of Boston Scientific . The WATCHMAN device does not cure atrial fibrillation . A stroke can occur as a result of factors not related to a clot traveling to the brain from the left atrial appendage . Other causes of stroke can include high blood pressure and narrowing of the blood vessels to the brain .
35