Our guest for this episode of Dr. Talks is a well known cardiologist Dr. Jagdish Hiremath. Dr. Jagdish serves as the Director Cath Lab, Ruby Hall Clinic, Pune, India.

Dr. Jagdish helps us understand the important role being played by Nuclear imaging in enabling medical experts make informed and objective clinical decisions.

He shares his own case experiences and highlights how imaging technology enabled doctors to make correct decisions in complex health scenarios.

Happy Listening!!!


Cardiac nuclear imaging is driving better clinical decisions. A review and illustration based on medical cases.

A talk with Dr. Jagdish Hiremath

Mr. Vivek
Hello, Welcome to Dr Talks. This is your host Vivek. Here we chat with the best doctors about diseases and conditions they treat. Our guest today is Dr. Jagdish Hiremath.

Dr. Jagdish Hiremath is a well known cardiologist based in Pune. Welcome Dr. Jagdish.

Dr. Jagdish
Hello Vivek. Thank you for inviting me to Dr. Talks.

Mr. Vivek
Dr. Jagdish, though you need no introduction, but for the benefit of our listeners, it would be great if you can share your journey in the field of medicine and specifically cardiology.

Dr. Jagdish
I am a product of Pune, educated here upto schooling, then medical college. I did my MD medicine from Sasoon Hospital BJ Medical College in 1983, went on to do my DM cardiology in Mumbai and then one year I spent in Melbourne, Australia, to learn the tricks of coronary angioplasty and that has been my expertise. I have been practicing that for almost thirty/thirty one years in Pune. I also went on to get some more degrees and fellowships from the US. So my practice has been interventional cardiology which involves angioplasties but I enjoy overall cardiology and it’s been an extremely pleasurable journey. Cardiology is a vibrant field, it gives you a lot of job satisfaction.

Mr. Vivek
Can you give us an overview of Cardiac Imaging and its role in heart treatment?

Dr. Jagdish
Cardiology deals with hearts. Easily the most important organ of the human body. When the heart stops, it is dust to dust. When dealing with heart, the treating doctor has to get excellent data/information about it so that right steps are taken. Cardiac imaging is one such field, which gives vital information to the treating cardiologist. In many cases the “imaging” becomes the turning point of the treatment, outcome and future of the individual. Fortunately imaging in the heart has improved leaps and bounds over the last few decades. Other investigations like some blood tests give selected information. ECG, Stress test, Holter give another set of information.

Technically echocardiography, coronary angiography are also imaging techniques. They are well established and have been around for many decades. Cardiac MR, CT scan of the heart have heralded on the scene but today we shall see cardiac imaging based on Nuclear Medicine and how it has enhanced precision of decision making.

Nuclear imaging of the heart involves radioactive nuclear tracer. It is injected in the body through a vein. As it travels with the blood and spreads in the heart, a special camera, Gamma camera, takes the pictures. Thus it is a non-invasive test where our body is not invaded by tubes or probes. The gamma camera can pick up areas that are highlighted by the nuclear substance. These images are interpreted by nuclear medicine experts, who are trained physicians, who have specialized postgraduate training. They handle the radioactive substances also. Nuclear imaging is used for all parts of the body but for the heart, it can bring on wonderful “Niche” information and help cardiologists plan precise therapy.

Mr. Vivek
Can you illustrate a case where nuclear imaging enabled a better informed treatment approach?

Dr. Jagdish
The first case that I would discuss is a fairly commonly discussed occurrence in heart patients. Mr. T. otherwise a normal individual, underwent routine checkup at the age of 40 as a part of his company checkup. The treadmill test was abnormal. An abnormal treadmill test indicates blockages in the coronary artery. Mr. T underwent coronary angiography and was found to have a 60% narrowing in an important artery. At a young age, there was a dilemma whether to provide preventive care or subject him to angioplasty and stent. In short the importance/significance of this narrowing/lesion was doubtful. A less than 50% lesion was a straightforward decision and > 75% lesion would have been clearly angioplasty. Such borderline blockages churn a lot of muddy water.

Nuclear imaging was used to solve this dilemma. Mr. T again underwent a treadmill test as before. At the peak of his walk on the treadmill when the highest heart rate is achieved, Thallium (Nuclear radioactive substance) was injected in this vein. The thallium reaches the heart and spreads along with blood flow in all 3 areas of the heart. At this stage, Gamma camera, which is like a scanner, took various images in various slices of the heart. Heart, the three dimensional structure is interrogated in a two dimensional modality. This done, Mr. T was made to come back to the Nuclear medicine department after 4 hours. By this time the Thallium gas stabilized in the heart and the Gamma camera repeats the series of images. (This takes a few minutes while the patient lies down quietly).

The nuclear physicist now compares the two sets of images and gives us Cardiologists the final impression. If the Thallium lights up an area, it is called hot and if it fails to reach that area, it is called cold. Mr. T. had all areas of the heart “hot” in both.

If Mr. T’s block was important /significant/causing flow restriction, the area supplied by that area would have remained “cold” in comparison to brisk blood flow in other arteries. After 4 hours, the blood would finally reach, get “redistributed” and would become “hot”. In technical terms “ischemic” area (area with less blood flow) will be cold at peak exercise because of high heart rate and work done by heart. It will slowly become hot in 4 hours.

In Mr. T’s case it never remained cold to start with. It was inferred that the 60% block was not important, it did not require any mechanical treatment like stent. Mr. T was advised only preventive treatment. The Thallium TMT was a game changer. He went on to become CEO of the company in the next 10 years. Repeated his Thallium test 3 times in 10 years.

The normal TMT raised a suspicion, coronary angiography gave a borderline verdict but Thallium provided direction. We commonly say TMT is sessions court, Thallium is High court, coronary angiography is Supreme court.

Mr. Vivek
Very interesting and insightful case. I am tempted to request you for another scenario which you can share.

Dr. Jagdish
Another use of Thallium like radioactive agent is to check “viability” of heart muscle. The heart muscle cell – myocardium – is an active living cell. It produces glucose, energy and this is known as metabolism. If the myocardium is metabolizing, it is living/viable.

If it is dead it will not metabolize. When a specific radioactive substance reaches the myocardium through blood. The cell actively “takes it up” by metabolism. Thus the cell becomes radioactive, hot and is captured as a “lit” area on a gamma camera. If it is dead, Thallium will not enter the cell and that area of the heart will be cold – unlit for the camera.

A fantastic life saving use of this “viability” test took place a few years ago in Diwali. A 10 year old over enthusiast decided to light up his home by coloured bulbs. Mishandled electricity and got a massive electric shock. He got flung about 6 feet and became unconscious.

His pulse was feeble and his heart was racing. His echocardiography showed an electrocuted heart. It was hardly moving and about to “give up”. Doctors proclaimed a near death situation. On the insistence of the mother, almost a corpse of the boy was brought to a bigger hospital. It was quickly realized that time was running out. The first test was a “viability” study with nuclear medicine. In an hour report was obtained – the heart was “viable” not dead. It was only stunned by the electric shock and was in a state of weakness. This prompted us to place advanced life support despite the poor finances of the family because there was now hope! All that needed was prolonged rest to the heart to let it recover. There are no magic medicines for such a condition. We installed Balloon pump in this 10 year old child to support the heart. Within 48 hours everything started improving and after 7 days a corpse like boy walked home with an ecstatic mother. All Diwalis, now our team gets home made mithai from this family. The nuclear imaging helped us employ this expensive treatment because it gave us hope that if supported, the heart will recover.

Mr. Vivek
I am amazed to hear this case. It shows the power and potential of technology coupled with medical expertise. It will be interesting to know more about other possibilities/scenarios where you have used imaging to manage complex health cases.

Dr. Jagdish
The Thallium, PET, Cardiac MR, Stress echo are tests that can ascertain whether heart is alive or dead, viable or non-viable. All have their merits and de-merits but when used judiciously they provide this vital information especially when the heart has become weak.

We have had instances when patient with multiple blockages and weak heart was sent for bypass surgery. Turns out on PET scan that the heart is non-viable – dead. Bypass surgery will be of no use. This person underwent heart transplant instead and now well for the last 2 years.
Other way round, a poorly pumping heart was relegated to “end of life” treatment was found to be “viable”. One single crucial angioplasty turned the tables of this person and he now runs half Marathon.

From viability and ischemia detection let’s move to some unusual utilities of nuclear imaging. It is a highly specialized field but now getting used after.

A 24 year old lady came to us with a blood pressure of 200/110 alarmingly high. She and doctors had been struggling with it for the past 6 months.

Career, marriage, pregnancy were on hold because of a volatile blood pressure. We subjected her to a PET scan. To our pleasant surprise a tumor “Pheochromocytoma” was detected at one spot in her body near the right kidney. She underwent this tricky but effective surgery. The blood pressure vanished and she now is a happy mum of two kids and a stable job in a bank.

This reminds me of another high-profile lady in her late forties. She had a pacemaker implanted for a slow pulse rate. After a few months of the implantation she started running low grade fever and mild pain in the site of the pacemaker.

As Cardiologists, one is very weary of Pacemaker infection because the wires are in direct connection with the heart and if the infecting germs travel along the wire electrodes it becomes a major life-threatening medical condition. Here in this lady, we had to be sure of infection at the site of the pacemaker and whether it had travelled in the heart.

PET Scan effectively showed us that a minor spot was noted at the pacemaker site below the collar bone. Not a speck of infection was noted inside the body. This made us confidently treat her with a short course of oral antibiotic. If PET scan has shown us infection along the electrode or on heart valves, we would have to resort to 4 weeks of intra-venous heavy antibiotics, removal and re- implantation of the Pacemaker. This was all avoided due to precise test to detect infection : Nuclear imaging by PET.

Thus nuclear imaging has come of age. It forms a turning point in decision making in Cardiology in above 15% to 20% of all cases. It is a non- invasive safe modality and for the information offered, it is highly cost effective.

I as a Cardiologist feel privileged to be practicing in today’s era of this advanced technology. I have seen the transition of practice. Without nuclear imaging, the clinical decisions were made on gut feeling and experience would be well intended but had a subjective element of error. Nuclear imaging has added remarkable objectivity in decision making of these cases. And this transition of using and not using nuclear imaging leaves me twitter pated, absolutely excited about management of patients.

Mr. Vivek
Dr. Jagdish, thank you for taking us through various kinds of imaging techniques and helping us understand their importance by sharing your case experiences which leveraged imaging technology. It was a pleasure to have you as our guest on Dr. Talks. Thank you.

Dr. Jagdish
Thank you Vivek. It was my pleasure to be on Dr. Talks.

Mr. Vivek
Dear listeners. Hope you enjoyed our insightful session on Cardiac imaging and the important role it plays in today’s era. Kindly share the podcast with your friends and spread the awareness in the community.
Cheers, till we meet next time.

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