QuPCG: Quantum Convolutional Neural Network for Detecting Abnormal Patterns in PCG Signals

Early identification of abnormal physiological patterns is essential for the timely detection of cardiac disease . This work introduces a hybrid quantum - classical convolutional neural network (QCNN) designed to classify S3 and murmur abnormalities in heart sound signals. The approach transforms one - dimensional phonocardiogram (PCG) signals into compact two - dimensional images through a combination of wavelet feature extraction and adaptive threshold compression methods . We compress the cardiac sound patterns into an 8 - pixel image so that only 8 qubits are needed for the quantum stage. Preliminary results on the HLS - CMDS dataset demonstrate 93.3 3 % classification accuracy on the test set, and 97.14% on the train set, suggesting that quantum models can effi-cientl y capture temporal - spectral correlations in biomedical signals. To our knowledge, this is the first application of a QCNN algorithm for bio acoustic signal processing . The proposed method represents an early step toward quantum - enhanced diagnostic systems f or resource - constrained healthcare environments.