Which non-invasive treatments can be used to treat abnormal heart rhythms?

Some, plus drugs: Depending on the cause & severity of the arrhythmia, relaxation techniques (medication, yoga, tai-chi) may be useful. Some anti-anxiety medications can be helpful as well. Beta-blockers are often used. Serious anti-arrhythmic agents are available, but some rhythm problems, especially in younger patients, may be amenable to electrophysiologic rx, like ablation, rather than lifelong drug therapy.

Cardioversion, meds: Use of anti-arrhythmic medications and shocking or resetting the heart (cardioversion) are non-invasive options.