Cardiac Stress Test: Nuclear Myocardial Perfusion Imaging

Dr. Rody Sy is one of the top cardiologists in the country. When I called his secretary requesting for an appointment not more than 2 weeks ago, I was informed that due to the huge number of patients under the doctor’s care, he does not accept new patients anymore. I was insistent and tried to convince her. After all, our late grandma was Rody Sy’s patient for several years. Also, i dropped the name of the company/organization where I work for just for good measure. Luckily, I got a call back from the secretary. I was ordered to submit my latest labs as well as undergo a 2-Dimensional Echocardiogram(2D Echo) with Doppler. The procedure uses ultrasound to picture out the heart. It provides a cross sectional image of the beating heart including its chambers, valves and blood vessels. Doppler assesses blood flow in and out of the heart.

I went to my appointment at the Cardinal Santos Medical Center(CSMC) with results in hand. Also, Electrocardiogram(ECG) was performed in his clinic. As his initial findings, Dr. Sy told me that it appears that I, for my age, still had a strong heart. He asked me what physical/athletic activities I engaged in before because he guessed that I did. It’s just that my pulse rate was a little bit on the high side. So he ordered another procedure and to see him in 2 weeks or when I have the new results in hand. he was so nice he even gave me discount cards and several free samples of my maintenance medication.

2 days ago, I underwent the Myocardial Perfusion Imaging with Technetium-99m Sestamibi at the National Kidney and Transplant Institute. NKTI Diagnostic Center is the newest building the the sprawling compound with modern equipment and facilities. The courteous and efficient staff made this long and difficult procedure seem pleasant. 2 days before the test, I was given a list of instructions that included a 4-hour fast before my scheduled procedure. The instructions also indicated that any and all medication that pertains to cardiac function be on hold for 24 hours before the procedure as well, and to be in comfortable clothing especially rubber shoes as the test involves running on a treadmill. There is a choice of which agent to use, either Thallium or Sestamibi. Dr. Sy did not specify. He wrote Thallium ‘or’ Sestamibi in his order. I was told Thallium is the ideal one since the image during the scan is easier to produce and you spend less time in the ‘bed’, and because of the shorter period, is actually cheaper. But the hospital’s Thallium supply was delayed overseas as this is imported from some other country. Therefore I was left with the other alternative, Sestamibi. I was told that I needed to set aside half a day to complete the test. It was really expensive too. They asked me to bring water and soda crackers. Which is the only food I can take after the exercise phase of the test.

Upon arriving, I was interviewed by a medical intern. It was a 4-page questionnaire covering family history of illnesses to present pain felt and current medication. They then asked me to change into a hospital gown. I was in shorts and running shoes. I should’ve asked someone to take my picture. I guess I looked ridiculous. Then an intravenous line was started by the technologist. This will be where the agent will be introduced before I lie down on the scanner. After half an hour, I was called into a room where the imaging equipment was located. It consisted of a flat, narrow bed and sort of a hollow sphere similar to the picture above. I was told to lie down with arms raised overhead and told not to move for 20 minutes.The bed started moving and in a few seconds the bed was halfway inside the spherical machine. A moving object came whirring very close to my chest. Moving laterally as if taking pictures from all angles.

It was so uncomfortable that I couldn’t hold my arms in that position any longer and they began to stray from its original position. I tried adjusting my arms back slowly thinking that it might not affect the scanning. After that episode, I was told to wait for about half an hour. Water was allowed and they encouraged walking around the corridors. I did that, unmindful of the stares I got because of my ridiculous outfit. Then it was time to repeat the scan. The technologist said that because of the small movement of my arms, the scanner failed to get a clear, isolated image. So into the tube I went again. Another uncomfortable 20 minutes. It helped that the staff, doctors and technologists were positive and encouraging. An hour’s wait  and more walking up and down the corridors, and I was called to the treadmill room. 

A harness of electrodes similar to an ECG was hooked up and we started to see the blipping image of my heart rate on the monitor. Baseline blood pressure(BP) was taken and it was at 140/80. Baseline resting heart rate was around 70 beats per minute(BPM). We waited a while for the cardiology fellow to arrive before the treadmill started to turn. I was told to take long steps. It really wasn’t running but more of a brisk walk. Also I was told that the target heart rate to reach is 145 BPM. After a few minutes in a comfortable pace, I heard a beep to indicate that it was time to take my BP. Same at 140/80. Then the treadmill shifted gears to a faster pace as well as raising the incline. The beep came, 90 BPM and 150/80. After each minute the angle and speed of the treadmill changed into a more challenging pace. When I reached the target 145 BPM, they gave me a choice to stop or to continue on. I opted to continue since the discomfort I felt was minimal. When I finally quit, I think it was 153 BPM, BP 190/100. The staff were all praises and told me that I have tolerated and finished the exercise phase well. After a minute or 2, BP was back to 140/80.

Now that surprised me because about 10 years ago, i did not finish a similar stress test. Utilizing the Bruce Protocol(the gradual increasing of pace and incline on a treadmill) then, my heart rate was still moderate but my BP was already high. I did not get to finish that test and I did not undergo that again until now.

After the ‘run’ I was told I can already eat my soda crackers and drink water. An hour of waiting and it was time to take the scan again. So back to the disagreeable position for another 20 minutes. Then again for the last time. Results will be released between 3 - 5 days. Hopefully, they are positive. But that little sequence of brisk walking made me realize how I miss regular physical activity. Again hopefully, I can get back to it.