The average length of time heart bypass patients have waited for surgery has nearly doubled across Wales.
Official statistics show patients waited an average of 79 days between April 2016 and March 2017, compared to 43 days in 2015-16.
Wales is lagging significantly behind the English NHS in six out of 11 of the main categories for procedures and diagnoses, other figures have shown.
The Welsh Government said it was working to cut bypass surgery waits.
England's average wait for a heart bypass was 51 days in 2016-17, 28 days fewer than in Wales.
The biggest difference between Wales and England was for hip operations, where the average was 215 days and 82 days respectively in 2016-17.
'It does make you a bit angry'
Meurig Williams from Llanrwst in Gwynedd has been waiting more than 18 months for a hip replacement.
He told BBC Radio Wales: "It will be nearly two years by the time I get it, I'm sure.
"I can walk. It is painful – I can walk on the flats but I can't go up a hill. It starts to get hot and it starts to burn and then it seizes up and I can't go any further."
Mr Williams said he was "ok" if he sat down, drove or lay down, adding: "So probably I'm lucky in a way compared to some people. I hear they're in terrible pain all the time.
"It does make you feel a bit angry that if you were in England you'd get it straight away."
Waiting times in Wales for the treatment of cataracts, hernias and the diagnosis of heart disease were also significantly longer than in England.
The Welsh NHS had shorter waits for kidney transplants and treatment for head injuries while both systems recorded the same results for the diagnosis of cancer.
The results were drawn from the headline figures measured in the hospital episode statistics from the English NHS and Patient Episode Database for Wales (PEDW).
Dr David Bailey, chairman of the British Medical Association's Welsh Council said: "The fact that Wales again lags behind England in the majority of waiting and diagnostic times is disappointing.
"The problem is quite straight forward, there are not enough doctors working in the Welsh NHS to cope with the ever-increasing workload and those that are working within the service are working at capacity to provide patients with the care they deserve."
Analysis by Nick Servini, BBC Wales political editor
These figures provide one of the very few opportunities to compare the performance of some parts of the Welsh NHS with the system in England.
It is the third time we have run the statistics and the broad picture has remained unchanged with far longer average waits in Wales in scheduled treatment for cataracts, hernias and for nearly 6,000 people who had a hip replacement last year.
The inevitable question is whether this is now the norm, and if so whether that is acceptable politically for a Labour Welsh Government which has been highly critical of the way the UK Government has run the system in England.
A Welsh Government spokesman said the PEDW data was "more than a year old and we do not use this data to measure performance".
He added: "There has been improvement in the length of time patients in Wales wait for treatment, with March 2017 showing a 57% improvement on the high of August 2015 in terms of the 36-week numbers.
"We invested a further £50m in August last year to reduce waiting times and we expect to see further improvement when the statistics for March 2018 are published.
"We are working to improve cardiac bypass surgery waiting times and speed up diagnosis for patients."
Welsh Conservative health spokeswoman Angela Burns said increasing waits for heart bypass procedures were "deeply concerning".
"We need an innovative and unashamedly target driven strategy to reducing waiting times – but there needs to be the will at Welsh Government level to accept that there is a serious crisis of management at the heart of the Welsh NHS,"she added.
Plaid Cymru health spokesman Rhun ap Iorwerth said his party had "consistently highlighted the unacceptably long waiting times in the NHS".
"It's why we've been calling for the Labour government to adopt a more rigorous approach to managing health board performance, drawing on the Scottish experience that successfully reduced waiting times in 2011," he added.
UKIP Wales health spokeswoman Caroline Jones said: "Yet again Wales is lagging behind England with Welsh patients having to wait longer for vital operations despite us spending more per head on health than England.
"This clearly shows it's not about how much money we spend, but how incompetently Welsh Labour has been running the NHS for almost 20 years."