The Covid-19 pandemic has disrupted access to health services globally for patients with non-Covid-19 conditions. We consider the condition of heart failure and describe a discrete event simulation model built to describe the impact of the pandemic and associated societal lockdowns on access to diagnosis procedures. The number of patients diagnosed with heart failure fell during the pandemic and in the UK, the number of GP referrals for diagnostic tests in November 2020 were at 20% of their pre-pandemic levels. While the numbers in the system have fallen clinicians believe that this is not reflective of a change in need, suggesting that many patients are delaying accessing care during pandemic peaks. While the effect of this is uncertain, it is thought that this could have a significant impact on patient survival. Initial results reproduce the observed increase in the number of patients waiting.