Cath Lab Digest - May 2008 - (Page 42)

42 ASK THE CLINICAL INSTRUCTOR MAY 2008 Figure 3a. In this figure, we see that the waveforms have been transitioned to match up, in order to take into account the delay in the pressure reading being read from the pulmonary capillary wedge (PCW). Once properly matched up, the computer can analyze the data. Figure 4. In this figure, a transseptal catheter has been placed in the right atrium (RA) and the septum between the RA and the left atrium (LA) has been punctured. Contrast is being delivered via the catheter to assure placement in the LA. You can also see a multi-purpose catheter that will soon be placed into the LV to obtain the pressure readings from both sides of the valve. If nothing else, remember that Pulmonary Capillary Wedge Pressure = Left Atrial (mean) = Left Ventricular End-Diastolic Pressure, or PCW=LAm=LVEDP. Figure 3b. In many systems, the default analysis of the mitral valve gradient includes increasing the sweep speed and decreasing the scale so that a more accurate measurement can be taken. Before computers were available to analyze the gradients, physicians or staff would use a planimeter (a cartography tool) to measure the highlighted area. We can all thank technology that we don’t have to do this! A catheter is again placed in the ventricle and another one in the LA. This is possible with an understanding of the anatomy of the heart. A special catheter set is inserted through the femoral vein and eventually into the right atrium (RA) (Figure 4). Under fluoroscopy, and possibly with the aid of transesophageal echo (TEE), the foramen ovale is identified and punctured, with the catheter being inserted over the device until it is in the LA. At this point, Principle #1 is met, and direct readings of the LA and LV are obtained and processed to provide the gradient reading. If your facility performs mitral valvuloplasty, then likely you complete this assessment numerous times during the overall procedure to evaluate the valve initially, as well as after each balloon inflation. (We will cover this in greater detail next month.) The transeptal procedure is not without risks, and should be reserved only for situations where the PCW pressure will not be reliable. It should also be performed by only the most skilled of physicians. It is a common procedure performed by electrophysiologists to complete certain ablation procedures. Both of these methods can provide information concerning the status of the mitral valve. ■ Next month, we’ll talk about the interventions that may be undertaken in the cath lab when we find these gradients in the aortic and mitral valves. “The only foolish question is one left unasked.” New Staff: Your suggested topics and questions are needed! (You are welcome to remain anonymous.) Email us at: tginapp@rcisreview.com

Table of Contents Feed for the Digital Edition of Cath Lab Digest - May 2008

Cath Lab Digest - May 2008 The King Faisal Specialist Hospital and Research Centre Cell Therapy in the Cath Lab for Heart Failure: A Look at MyoCell® Therapy and the SEISMIC Trial Performance Improvement Strategies Speed Up Treatment Times in the Management of ST-Elevation Myocardial Infarction (STEMI) Patients Contents Clinical Editor’s Corner Commentary: Performance Improvement Strategies Speed Up Treatment Times in the Management of ST-Elevation Myocardial Infarction (STEMI) Patients Ask the STEMI Expert Comparing Drug-Eluting Stents and Bare-Metal Stents SICP: The Ten-Minute Interview with… Christopher Kambak, RT(R) Cardiac Cath Lab Economics in a Public Hospital of a Developing Country Keeping Your Heart & Vascular Employees: Proven Ideas for an Effective Retention Plan Unspoken Words Ask the Clinical Instructor Society of Invasive Cardiovascular Professionals Meetings Calendar Education Center What Do You Think? Clinical & Industry News Classifieds Advertisers Index

Cath Lab Digest - May 2008

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