Dear thanks for posting here.
The likely cause of your husband's palpitations seem
PSVT as you have not mentioned any associated symptoms like
loss of consciousness during the palpitations (and I presume these symptoms are not there). PSVT is basically short circuiting of the electrical system of the heart.
This is a benign condition that can be easily treated but before that we have to be sure about the diagnosis.
Now for diagnosis, we need an ECG done during palpitations but as the duration of your husband's palpitations is quite short so I donot feel that it can be done.
The other way is EPS (Electrophysiological studies) which is an invasive method where in we introduce catheters inside heart and then try to induce the palpitations.
When diagnosed, we can ablate the abnormal electrical pathways so that no short circuiting occur again. All of this procedure is done with catheters that can be passed from one of your groin just like the
angiography is done.
BUT before all this, I would like him to get his
thyroid function tests to rule out any thyroid abnormality and
echocardiography done to be sure that his heart is structurally normal.
Hope you get your answers and all the best.