Background: Dynamic subaortic stenosis occurs in differing situations, commonly with hypertrophic cardiomyopathy. Regardless of the underlying cause, the resulting murmurs usually possess a characteristic sound spectr...Background: Dynamic subaortic stenosis occurs in differing situations, commonly with hypertrophic cardiomyopathy. Regardless of the underlying cause, the resulting murmurs usually possess a characteristic sound spectral pattern, manifesting a sharp and high frequency peak occurring late in systole, often bearing a striking resemblance to the subaortic Doppler flow pattern. Methods: Murmurs found in thirty one subjects with dynamic subaortic stenosis were analyzed after having been recorded with a novel portable device capable of spectral and waveform sound displays. Results: All subjects manifested characteristic frequency patterns, consisting of high and sharp peaks occurring in late systole. With significant subaortic stenosis (resting subaortic flow velocity > 2 m/sec) this pattern was evident at rest. In the presence of little or no resting subaortic obstruction (< 2 m/sec) this pattern was produced regularly by the Valsalva maneuver. Conclusions: Dynamic subaortic stenosis produces a specific sound spectral pattern that may provide a basis for clinical evaluation, especially in early detection of this disorder and in screening situations.展开更多
针对传统心音去噪算法对强噪声下心音信号去噪时,易将部分心音信号视为噪声成分去除,导致有用心音信号能量损失。利用奇异谱分析方法的主成分分析特性,提出多级奇异值分解(Multi-stage Singular Value Decomposition,MS-SVD)算法用于提...针对传统心音去噪算法对强噪声下心音信号去噪时,易将部分心音信号视为噪声成分去除,导致有用心音信号能量损失。利用奇异谱分析方法的主成分分析特性,提出多级奇异值分解(Multi-stage Singular Value Decomposition,MS-SVD)算法用于提取心音信号的主分量(Principal Components,PC)信息;采用小波包(Wavelet Packet,WP)分析算法对提取的心音信号进行分解,并对分解所得低频系数进行自适应阈值处理,去除低频噪声;利用小波包多分辨率特性提取高频心音。实验结果表明,该算法能明显改善心音去噪性能指标信噪比(SNR)、信噪比增益(SNRG)及根均方误差(RMSE),且在不同噪声水平下的去噪性能优于传统心音去噪算法。此改进算法既能有效去除心音中噪声成分,亦能保留心音信号细节特征。展开更多
文摘Background: Dynamic subaortic stenosis occurs in differing situations, commonly with hypertrophic cardiomyopathy. Regardless of the underlying cause, the resulting murmurs usually possess a characteristic sound spectral pattern, manifesting a sharp and high frequency peak occurring late in systole, often bearing a striking resemblance to the subaortic Doppler flow pattern. Methods: Murmurs found in thirty one subjects with dynamic subaortic stenosis were analyzed after having been recorded with a novel portable device capable of spectral and waveform sound displays. Results: All subjects manifested characteristic frequency patterns, consisting of high and sharp peaks occurring in late systole. With significant subaortic stenosis (resting subaortic flow velocity > 2 m/sec) this pattern was evident at rest. In the presence of little or no resting subaortic obstruction (< 2 m/sec) this pattern was produced regularly by the Valsalva maneuver. Conclusions: Dynamic subaortic stenosis produces a specific sound spectral pattern that may provide a basis for clinical evaluation, especially in early detection of this disorder and in screening situations.
