zafar.ahmad

Zafar Ahmad

Cardiovascular signal processing & deep learning

I investigate cardiac timing and wearable sensing, and help research and engineering teams turn recordings into reproducible analysis.

Islamabad, PakistanMS Electrical Engineering · NUST

Open to PhD opportunities in cardiovascular digital health · Taking signal-processing projects

01At a glance

  • 2first-author conference papersICAI 2023 · EUSIPCO 2024
  • 2ESC Congress 2026 presentationsMunich · presenter
  • 3journal manuscriptsRevision / last-reported review · 9 Oct 2026
  • 5.0Fiverr rating6 reviews · Level 1 · 12 Oct 2026

02Who is Zafar?

I’m a cardiovascular signal-processing engineer and researcher. One question connects my work: how the heart’s electrical activity relates to its mechanical and acoustic consequences, and how that relationship can be read from ECG, heart-sound (PCG) and optical-pulse (PPG) recordings.

It began with paediatric heart-sound collection in hospitals and schools in Pakistan, where I learned what cardiologists need from a recording. Since then I have worked on deep-learning models for cross-modal ECG–PCG reconstruction and a wearable research prototype for time-aligned ECG, PPG and motion. I am also developing a probabilistic model of coupled cardiac events.

Alongside research I take on audio and biomedical signal-processing projects — spectral analysis, comparison reports, classifiers and analysis tools. For my PhD, I want to investigate whether signal-derived cardiac timing can constrain patient-specific physiological models, with uncertainty and device differences treated explicitly. My current modelling is statistical and data-driven; physiological modelling and prospective validation are skills I want to develop during a PhD. My doctoral question.

03Research focus

MS thesis · NUST

Cross-modal ECG–PCG reconstruction

A conditional GAN with multi-scale attention reconstructs an ECG-like timing reference from heart sounds; phase-aware features then target murmur presence, grade, timing and shape.

Current finding · Oct 2026 In a patient-grouped evaluation, expert-reviewed phase boundaries carried useful information; the tested synthetic-ECG timing route did not establish an advantage over equal-time windows.

Read the study

CAREON · NUST

Wearable ECG · PPG · motion

An ESP32 research prototype with AD8232 ECG, MAX30102 PPG and MPU6050 IMU sensors. I set 250 Hz ECG and 100 Hz PPG sampling targets and specified a 16-bit external ADC fallback for acquisition precision. Timing fidelity and motion sensitivity remain to be evaluated.

The ECG-to-pulse delay includes pre-ejection time, so it is not treated as isolated pulse transit time.

Project details

Qatar University · in development

Probabilistic electromechanical coupling

Copula-based coupled hidden Markov models: one chain for ECG waves (P, QRS, T), one for heart-sound phases (S1, systole, S2, diastole), and a copula for their non-linear dependence.

Approach

Published · ICAI 2023 · EUSIPCO 2024

Heart-sound classification

ICAI 2023: a time-domain 1D CNN with pitch-shift augmentation for binary paediatric congenital-heart-disease detection. EUSIPCO 2024: band-selective pitch augmentation and MFCC features for a separate five-class valvular/normal heart-sound benchmark.

Both papers
Zafar Ahmad presenting at Station 4 beside his poster at ESC Congress 2026 in Munich
ESC Congress 2026 · Munich · 28 Aug Presenting the murmur-gating poster. Its earlier results are softened in the photo because the later patient-grouped evaluation supersedes them.

04Tech stack

  • LanguagesPython (primary) · MATLAB / Simulink
  • Deep learningPyTorch · TensorFlow · Keras · conditional GANs · self-attention · 1D/2D CNNs · TensorFlow Lite export
  • Signal processingSTFT · CWT · Welch & multitaper PSD · MFCC · envelopes · R-peak & pulse detection · resampling
  • Modelling & statisticsCopulas · coupled HMMs · system identification · patient-grouped cross-validation · paired uncertainty
  • Hardware & dataESP32 · AD8232 · MAX30102 · MPU6050 · electronic-stethoscope field recording · PhysioNet corpora
  • ToolsGit · GitHub · Linux · GPU training · LaTeX · Matplotlib

05Freelancing

I help researchers, engineers and product teams get reliable answers from messy real-world signals — with clear methods, reproducible outputs and stated limits.

Hire me on Fiverr

5.0 from 6 reviews · Level 1 seller · profile snapshot, 12 October 2026

  • 01

    Spectral analysis of audio

    Digital spectra, level, noise-floor and channel comparisons across recording conditions, with a structured report and stated measurement limits.

  • 02

    Biomedical & audio DSP

    Filtering, segmentation, feature extraction and recording investigation for PCG, ECG and difficult audio.

  • 03

    Deep-learning signal classifiers

    ECG, heart-sound and acoustic classification projects, with data, evaluation and deliverables agreed before development.

  • 04

    Wearable monitoring prototypes

    Sensor integration and signal pipelines for wearable ECG and PPG prototypes.

Selected public Fiverr reviews

“He keeps timelines and even for a not so tech person made me understand the steps and the processes.”

Fiverr client · United States

“As always Zafar was receptive, involved and exceeded all expectations.”

Fiverr client · United States · ongoing collaboration

“Very Professional. Delivered on time. Highly recommend.”

Fiverr client · United Kingdom
Engineering case studies and a reproducible output sample

06Experience

CAREON · NUSTResearch Assistant & Team Supervisor · IslamabadDec 2025 — Present
  • Lead technical work on a wearable research prototype that records time-aligned ECG and PPG with an inertial sensor for motion-artefact analysis.
  • Set sampling and synchronisation targets, identified the microcontroller ADC’s amplitude-resolution limits and specified a 16-bit external ADC fallback.
  • Supervise three research apprentices across embedded firmware, sensor integration, signal processing and the cloud data pipeline; coordinated pilot recordings with consenting volunteers.
  • Led the blind cross-device audit of the PCG-to-ECG reconstruction model on 338 record pairs; it did not establish successful transfer to the new hardware.
Qatar UniversityResearch Assistant · Multimodal Cardiac Signal Modelling · RemoteMay 2023 — Present
  • Designed band-selective pitch augmentation that keeps the diagnostic band intact, with an MFCC-based 1D CNN for five-class heart-sound classification (EUSIPCO 2024, first author).
  • Developing a copula-based coupled hidden Markov model for simultaneous ECG and PCG (since September 2024).
  • Exploratory ECG–PCG dependence analysis at rest and during exercise: pooled sample-level correlation was weak; the ongoing formulation examines event-level dependence and synchronisation.
  • Co-wrote a submitted grant proposal on simultaneous PCG and ECG analysis (Qatar University Office of Research Support, September 2025).
Freelance · FiverrAudio & biomedical signal-processing engineer · Remote2024 — Present
  • Recording investigation, repeated acoustic comparison reports and an offline audio-to-motion prototype for international clients. The engineering portfolio also documents a compact-model export workflow with scope stated in the case study.
  • A 5.0 rating across six reviews in the 12 October 2026 profile snapshot; clients highlight clear explanations and on-time delivery.
NCAI · UET PeshawarResearch Apprentice · AI in Healthcare LabJun 2021 — May 2022
  • Collected paediatric heart sounds with an electronic stethoscope at two tertiary hospitals and six schools, with cardiologist-supported, echocardiography-confirmed annotation.
  • Wrote the collection procedures, consent documents and clinical questionnaires used for institutional review; took part in school screening and referral.
  • Trained 1D convolutional networks with pitch-shift augmentation for paediatric congenital-heart-disease detection (ICAI 2023, first author).
  • Best Summer Intern Award, 2022.

Education

2023 — 2026

MS Electrical Engineering · NUST, SEECS

Thesis: Cross-Modal Reconstruction of Cardiac Signals: Decoding ECG-PCG Electromechanical Coupling Dynamics. Supervisor Dr. Nazia Perwaiz; co-supervisor Dr. Muhammad Salman Khan. CGPA 3.20/4.00, thesis grade A.

2018 — 2022

BS Electrical Engineering (Communication) · UET Peshawar

Final-year project on paediatric congenital-heart-disease detection from heart sounds (published at ICAI 2023). CGPA 3.21/4.00, project grade A.

07Publications & talks

Journal statuses below were last reported on 9 October 2026. These manuscripts are not accepted or published; conference papers and congress presentations are listed separately.

  1. Published

    Phonocardiogram Classification Based on 1D CNN with Pitch-Shifting and Signal Uniformity Techniques

    Z. Ahmad, M. S. Khan, M. E. H. Chowdhury, S. Zughaier, W. H. Ibrahim · EUSIPCO 2024, pp. 1536–1540 · DOI

  2. Published

    Automatic Detection of Paediatric Congenital Heart Diseases from Phonocardiogram Signals

    Z. Ahmad, M. Zeeshan, A. Sohail, Fazal-e-Haq, M. Haris, M. U. Khan, S. S. Hussain, M. S. Khan · ICAI 2023, pp. 188–195 · DOI

  3. Minor revision

    PCG-to-ECG Signal Reconstruction Using Conditional GAN with Multi-Scale Attention

    Z. Ahmad et al. · IEEE Journal of Biomedical and Health Informatics · revised July 2026; under review, not yet accepted

  4. Major revision

    Synthetic-ECG-gated phonocardiography for paediatric heart-murmur characterisation: a cross-modal deep-learning method

    Z. Ahmad et al. · European Heart Journal – Digital Health · revision requested September 2026; not yet accepted

  5. Last reported

    Parallel multi-scale analysis for paediatric heart disease classification from phonocardiograms

    M. S. Khan, Z. Ahmad, H. Nayab · IEEE Journal of Selected Topics in Signal Processing · submitted November 2025; last reported under review as of 9 October 2026

  6. ESC 2026

    Synthetic ECG-guided temporal gating improves paediatric murmur grading, timing, and shape classification on the CirCor DigiScope dataset

    First author & presenter · 28 Aug 2026 · abstract 83190 · ESC 365 · title as presented; superseded by the October evaluation

  7. ESC 2026

    An explainable calibrated concept bottleneck model with evidence-constrained large language model reporting for multi-label valvular heart disease screening from 12-lead ECGs

    Co-author & presenter · technical supervision · 31 Aug 2026 · abstract 86479 · ESC 365

Grant proposals co-written (submitted, not awarded): HEC Pakistan National Research Programme for Universities, and Qatar University Office of Research Support, both September 2025.

// next step

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