Objective To investigate the application of nursing intervention based on root cause analysis in patients with hypertension and left heart failure. Methods A total of 80 patients with hypertension and left heart failure who were treated in Qilu Hospital of Shandong University from January 2020 to June 2022 were enrolled and divided into control group and observation group using a random number table, with 40 patients in each group. The patients in the control group were given routine nursing, and those in the observation group were given nursing for protection against cardiogenic stress in addition to the routine nursing in the control group. The two groups were compared in terms of myocardial function, stress response, and recovery time. Results Compared with the control group, the observation group had significantly lower levels of myocardial injury markers after nursing, as well as significantly lower systolic blood pressureand heart rate and a significantly higher arterial oxygen saturation at 60 minutes after nursing started (P<0.05). After nursing, the observation group had significantly lower anxiety and depression scores than the control group (P<0.05). Conclusion In patients with hypertension and left heart failure, nursing intervention based on root cause analysis can reduce the degree of myocardial injury and stress response.