Inclusion Criteria:  Age 18-80 years. Provision of signed informed consent prior to any study-specific procedure Selected for Hybrid Rhythm ablation surgery (ISNT, VT, AF) American Society of Anesthesiologist physical Status I to III Dutch, French or English speaking Ability to follow the study protocol  BMI > 35 kg/m2 . BMI or Body mass index will be obtained from body weight in kg divided by the square of the length in meter and is expressed in kg/m2  -  Exclusion Criteria:  a. History of chronic pain or drug treatment abuse b. Depression, psychiatric morbidity or mal-adaptive coping behaviour c. Neuropathy d. Severe anxiety or other mental ailment, taking drugs affecting their capacity to assess pain (gabapentin, pregabalin, opiod use) e. Chronic or acute skin infection of the back or the lateral thorax f. Hypersensitivity to ropivacaine g. Severe hepatic, renal , pulmonary or cardiac (EF < 30%) disease or refuse to participate to the study..