But, you can't exclude the combined folks. Those people are planning on an academic career or maybe, a top Private practice doing Cardiac if the pay is $600K plus.
The combo fellowship of CCM/Cardiac is a good investment in your academic career which for many is 30+ years. At my age you begin to realize that health matters more to your income productivity over 30 years than the 1-2 years lost in fellowship. So, if those fellowships get you a sweet gig with lots of perks, time off, time to exercise daily, etc. the odds favor that individual over the others who went straight into a grueling private practice (no fellowship) working 60 hours per week or more.
https://smartasset.com/taxes/income-taxes