Abstract:

Objective To discuss the clinical characteristics of the patients with hypertrophic cardiomyopathy （HCM） complicated with microcirculatory dysfunction （CMD）， and to analyze the impact of concurrent CMD on the prognosis of the HCM patients. Methods A total of 211 patients diagnosed with HCM and having complete cardiac magnetic resonance imaging （CMR） examination results from January 1， 2019 to September 30， 2023 were collected. They were divided into HCM complicated with CMD group （68 cases） and HCM complicated without CMD group （143 cases） based on CMR assessment. The clinical data such as age， gender， admission symptoms， and past medical history， blood test data such as troponin， electrocardiogram， echocardiography， and CMR data including abnormal Q wave， ST segment depression， inverted T wave， PR interval， QRS wavelength， corrected QT interval， ejection fraction （EF）， left atrial diameter （LAD）， left and right ventricular end-diastolic diameters， cardiac output， E peak， A peak， and maximum wall thickness （MWT） of the patients were compared between two groups. Logistic regression was used to analyze the clinical characteristics of the HCM patients complicated with CMD； multivariate modified Poisson regression was used to analyze the risk factors for major adverse cardiovascular events （MACE） in the HCM patients. Results Compared with HCM complicated without CMD group， the percentage of palpitation patients in HCM complicated with CMD group was significantly increased （P<0.05）， the percentage of tachycardia episode patients was significantly increased （P<0.05）， the troponin level was significantly increased （P<0.05）， and the percentage with a history of hypertension patients was significantly decreased （P<0.05）. Compared with HCM complicated without CMD group， the percentage of abnormal Q wave on electrocardiogram in the patients in HCM complicated with CMD group were significantly increased （P<0.05）， the percentage of inverted T wave and the EF of the patients was significantly decreased （P<0.05）， the LAD was significantly increased （P<0.05）， and the MWT was significantly increased （P<0.05）. The multivariate Logistic regression analysis results showed that increased LAD （OR=1.05， 95%CI： 1.00-1.11， P=0.048） and increased MWT （OR=1.11， 95%CI： 1.03-1.19， P=0.007） were the risk factors for concurrent CMD in the HCM patients； history of hypertension （OR=0.40， 95%CI： 0.20-0.80， P=0.010） was a protective factor for concurrent CMD in the HCM patients. The average follow-up time in this study was 20.5 months. A total of 27 patients experienced MACE， with an overall incidence of 12.80%， including 12 patients in HCM complicated with CMD group and 15 patients in HCM complicated without CMD group. The multivariate modified Poisson regression analysis results showed that history of diabetes （RR=2.34， 95%CI： 1.09-5.06， P=0.030）， history of arrhythmia （RR）=4.00， 95%CI： 1.82-8.83， P=0.001）， and decreased ejection fraction （RR=0.96， 95%CI： 0.94-0.99， P=0.001） were risk factors for MACE in the HCM patients. Conclusion The HCM patients complicated with CMD have unique clinical characteristics， including higher symptom burden， left atrial enlargement， myocardial hypertrophy， and increased troponin levels. Concurrent CMD does not increase the short-term risk of adverse events； diabetes， arrhythmia， and decreased EF are key risk factors for prognosis； early intervention and complication management for HCM complicated with CMD patients may improve the long-term prognosis of the HCM patients.

Key words: Hypertrophic cardiomyopathy, Microcirculatory dysfunction, Clinical characteristics, Adverse cardiovascular events, Cardiac magnetic resonance imaging