New guidelines for the management of hypertrophic cardiomyopathy have emphasised the importance of shared decision making to improve confidence in clinical decisions and improve health outcomes.

Leading the top 10 take-home messages in the 2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy is advice for discussion between patients and their care team “that includes full disclosure of all testing and treatment options, discussion of the risks and benefits of those options and, importantly, engagement of the patient to express their own goals”.

Co-author on the guidelines Professor Christopher Semsarian told the limbic decisions around competitive sport was an example where discussions could be better informed by shared decision making involving the patient and their family, and including their values and preferences.

“For decades, if you had hypertrophic cardiomyopathy you were told not to play competitive sports and not to compete at a high level, and to avoid high level athletic sports. But over recent years there has been a lot of evidence that the risk/benefit ratio … the chance of dying on a football field is extremely low.”

“What was happening is we were telling people not to play competitive sports and then they weren’t doing any exercise and ending up with obesity and diabetes and coronary artery disease and all sorts of complications from not exercising.”

“And so getting the patient involved in the decision making is important, rather than us just saying you can’t play sports.”

Professor Semsarian said there had been a lot of change in many areas since the last guidelines document in 2011.

“Over the last nine years since the last guidelines, the knowledge and understanding of genetic causes of hypertrophic cardiomyopathy have improved dramatically. That, coupled with the fact you can do genetic testing much cheaper and it’s much more accessible to the general population, means it is having a much bigger impact on diagnosis and the management of patients as well.”

He said while there were still some people happy to just have yearly echocardiograms – the gold standard for decades – genetic testing was now more mainstream.

“The recommendation is that everyone with hypertrophic cardiomyopathy should at least have the discussion about doing a blood test to find the genetic cause. Firstly because if you find a genetic cause, you might help manage the patient in front of you better. Secondly, it can help screen other family members to see if they do or don’t carry the gene change. And thirdly, it can help in reproductive decisions as well – IVF processes where you can actually select [out] embryos that have the genetic change and not implant them.”

He said uptake of genetic testing at the Royal Prince Alfred Hospital HCM clinic was more than 90%.

Professor Semsarian said the new guidelines also emphasised the importance of such specialised clinics.

“Because hypertrophic cardiomyopathy is a quite a complex disease, the preference is for all patients to be seen in specialised, multidisciplinary centres.”

He said while the general cardiologist can manage much of the patient’s care, where possible it was important to at least link the patient and family to a specialised clinic that could encompass clinical care, research, genetic evaluation and counseling, psychological care, etc.

The correction application of septal reduction therapies, such as medication, myectomy or alcohol ablation, was one example where a specialised team was warranted.

Other key messages from the 74 page set of guidelines include:

• Counselling patients with HCM regarding the potential for genetic transition of HCM is a cornerstone of care.
• Echocardiography remains the foundational imaging modality however, cardiovascular MRI is also helpful where there is diagnostic uncertainty, poor echocardiographic imaging windows, or uncertainty regarding ICD placement.
• Assessment of an individual patient’s risk for sudden cardiac death (SCD) continues to evolve as new markers emerge e.g. apical aneurysm, decreased left ventricular systolic function, and extensive gadolinium enhancement.
• Risk factors for SCD and thresholds for ICD implantation differ in children and adults.
• Anticoagulation is the default strategy for patients with HCM and persistent or paroxysmal AF – independent of CHA₂DS₂VASc score.