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ASRT CME is not available.
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The echo exam shows spontaneous echo contrast in the LA and a hockey-stick formation and hypomobility of the mitral valve. The mitral valve is thickened. The LAA is without thrombus. The left and right atrium are enlarged. The mitral valve has a PISA formation. The PHT of the MV is 318-164 msec for a MVA of 0.60 - 0.68 cm2.
The left atrial appendage peak velocity is 0.28 m/sec.
The aortic vale is hypomobile, thickened, and shows fibrosis at the commissures. The CFD shows severe AR with a wide jet that extends into the apex of the LV. The PISA formation of the AV during diastole has a radius of 0.79 cm (although this looks larger than that to me :). The LOVTd is 2.22 cm. The AV has stenosis but no Doppler studies are available to assess the severity.
The tricuspid valve has severe MR by jet area on CFD and by hepatic vein Doppler. The IVC is enlarged.
The anterior and inferior walls have normal motion. The septal wall exhibits a septal bounce at the beginning of diastole - presumably from the severe AR.
The patient has severe aortic regurgitation, severe tricuspid regurgitation, aortic stenosis of unknown severity and severe mitral stenosis from rheumatic heart disease. The pulmonary valve was spared.
The recommended therapy is MV and AV replacement and TV annuloplasty.
After the operative therapy the valves were interrogated. The TV had a very small gradient. The MV peak gradient was 9 mmHg which should put the mean gradient around 5-6 mmHg. The AV peak gradient was in the low 20's mmHg.
Also after the operative therapy a new onset LBBB was present that simulated an anterior wall motion abnormality.
Biventricular pacing is indicated in heart failure. In the operating room it is indicated for patients with a wide-QRS with hypotension due to cardiac dissynchrony. The specific indication according to the ACC/AHA/HRS 2008 pacing guidelines are:
Biventricular pacing is indicated if the LVEF is less than 35% or a QRS that is wider than 0.12 msec and cardiac failure is present despite optimal medical therapy as a Class I/Evidence A recommendation.
Wang showd an increase in cardiac output of 10% when Bi-V pacing was initiated. Dzemali showed that 59% of patients responded to Bi-V pacing with improved hemodynamics. 40% did not show any improvement.
Luzi tried different locations on the RV to find the best site for BiV pacing. The sites were the interventricular septum, the pulmonary trunk, the AV junction and the acute margin. The best site that provided optimal BiV pacing was the interventricular septum.
Other authors showed that biventricular pacing did not improve the hemodynamics of the patient. It appears that about 30% of patients will not respond to BiV pacing. Using the newer 3D TEE machines you can view the septal to lateral delay before and after BiV pacing and optimize the delay in the operating room.
The advantages of biventricular pacing are to:
Decreased Systolic Time -> Increased Diastolic Filling Time
Improved Stroke Volume/Ejection Fraction
Earlier Closure of the Mitral valve
The MUSTIC and MIRACLE trials showed hemodynamic improvement in patients with heart failure who underwent biventricular pacing. Ventricular remodeling can also occur. The mitral regurgitation that was present had decreased.
Biventricular pacing requires 2 dipoles (one lead on the heart and one lead for a ground) that are 180 degrees apart in the heart. Therefore, you should have 4 wires - two attached to the heart 180 degrees apart and a ground for each cardiac lead. Usually, the atrium is paced also. To pace the atria a similar arrangement should be present. The inferoseptal wall and anterolateral wall or the anteroseptal wall and inferolateral wall are 180 degrees apart.
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ACC/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities
Optimized temporary biventricular pacing acutely improves intraoperative cardiac output after weaning from cardiopulmonary bypass: A substudy of a randomized clinical trial
Optimized perioperative biventricular pacing in setting of right heart failure.
The effect of biventricular pacing after coronary artery bypass grafting: A prospective randomized trial of different pacing modes in patients with reduced left ventricular function
Best Site on Right Ventricle for Open-Chest Biventricular Pacing
Intraoperative Biventricular Pacing - PCCVS
Benefit of cardiac resynchronization in elderly patients: results from the Multicenter InSync Randomized Clinical Evaluation (MIRACLE) and Multicenter InSync ICD Randomized Clinical Evaluation (MIRACLE-ICD) trials.
Long-term benefits of biventricular pacing in congestive heart failure: results from the MUltisite STimulation in cardiomyopathy (MUSTIC) study.