Logic would dictate that since a left-handed individual with the heart on the left-side uses his right hand, so too an individual with situs inversus would use the left hand. I have not looked at any literature on the matter though.

And what about the Doctor?

I think I saw this discussed in one of Raabi J DavId Bleich's books.

No sources but since the reason that we bang on our hearts is because it is "the heart that led us astray to sin" what would be the purpose of banging over an area where the person's heart is clearly not there (not that you need a direct hit, but you should be in the at least in the ballpark ) So in your case he should bang on the right side using his right hand.

There is no halocho to pound your chest anywhere during tafillo. On the contrary the halocho states that you should hand your right hand over your left over your heart. No reason to find a way to do something which is already not a halocho or even a clear cut minhagh yisroeil

@MoriDoweedhYaa3qob It says in the Chabad siddur (in the footnotes) yake al halev, yake means hit (like make bepatish), but you're right, you don't need to do it hard, you can do it very gently, but whatever it is, my question still stands

@user3949142 the chabad siddur is not a seifar for halochoth. you dont quote a siddur for halocho you quote a seifar of halochoth like the jamoro or meeshnei toro. therefore your question doesnt stand for there is no reason for doing this

@MoriDoweedhYaa3qob fine, so which side does he put his hand over (and I'm not sure where it says he puts his hand over)

@user3949142 on his chest right over left hand

@MoriDoweedhYaa3qob On which side of the heart? And if you're saying you use both hands, where does it say sucha thing?

@user3949142 i said place your right hand over your left on your chest. i didnt say strike your hand on your chest. it says so in the jamoro in masachath shabboth 10a and brought down again by the rambam zl in heelchotch beerkath kohaneem chpt 5 halocho 4. i recomend tou read the entire chapter there for proper way of prayer. especially bout the bowing properly during tafeello

I think I remember seeing the answer somewhere. If you give me some time I can try to check

@Bochur613 You have as long as you need. This question is unlikely to get deleted.

It's only a custom, and not a particularly important one. The actual heart muscle doesn't control emotions. "Heart" is a metaphor, used in both Jewish and secular Western writings, to refer to the emotions. Since the actual heart muscle has nothing to do with the emotions that led a person to sin, and this isn't a chiuv in any case, this whole question is moot.

@Jake Every minhag is important. The talmud yerushalmi (and some minhagim follow this) puts matbilim (which is a minhag) as the first question in the ma nishtana to teach us the importance of a minhag.

@Jake And btw, minhagim ARE chiyuvim.

@user3949142 so every male Jew is required to wear Rabbeinu Tam tefillin every morning? Every male Jew is required to wear a shtreimel on shabbat? Apparently, minhagim are not chiyuvim. There are some minhagim that great rabbinical leaders have decreed should be observed as if they are binding law (e.g. wearing a kipah) , but this particular minhag has never been elevated to a takanah d'rabannan.

@Jake Being that it's not OUR minhag to wear a streimel, so we don't need to. It's my minhag to put in rabeinu tam, so i have to

@user3949142 a chiyuv is an obligation. Sectarian customs among certain groups of Jews are not obligations. You personally may have an obligation to follow the customs of your father, but that doesn't make every minhag ever invented a binding obligation on all of klal yisrael. Furthermore, a chiyuv can't be removed, but a minhag can be. If you moved to a place where no one wore rabbeinu tam tefillin, and doing so in shul would make you look haughty, you would be allowed to do hataras nedarim, and stop wearing them. Not so with a chiyuv, even one that a community is lax on keeping.

@Jake possibly you're right (although I don't agree about mechezei k'yehura-appearing haughty applying to r"t b/c i don't think you can be matir neder for doing a mitzva, and shulchan aruch says a yirei shamayim should put on r"t) but still, my question is still a question, you can't just make up that this is not an important minhag and thus we don't need to worry about the technicalities

@user3949142 you can't make up that this is an important minhag , that deserves to be darshened and paskened on. If you have a source which highlights the extreme importance of tapping the part of the chest which directly hovers over the heart muscle, then please add it to your question.

@MoriDoweedhYaa3qob In the Chabad siddur, it says that banging the heart was the minhag of the Rebbe. I assume it's the minhag of many other people, so don't just write it off.

@Jake So don't answer this question. This question is for people who care about minhogei yisroel and prefer not to spell minhag (in Hebrew) backwards but do it properly. As i said, the point of matbilim being first is to teach us not to treat minhagim lightly (i can give you a lot of sources where it makes that connection).

@user I just did write it off. Like I said a siddur if habas is not halocho. Bring me a jamoro or rambam and then we will talk. His or anyone else's minhagh means nothing to me

@user a minhagh of yisroeil means ALL yisroeil accepted this minhagh such as maa3reebh. The habad sect is bit ALL if yeesroeil, hassidim are not all of yisroeil, ashkanazim are not all of yisroeil

@user like jake said, it is a thing which was created as a metaphorical gesture. It has nothing to do with the halichoth of tafillo. Standing and praying and holding your hands on your chest right over left like a 3abadh is also metaphorical so it bowing down and prostrating. For this is how a person acts before a king. However, these metaphorical gestures are written in the tanach as well as 7azal, pounding your chest doesn't