The various embodiments of the present invention disclose a stand-alone, scalable cardiac health monitoring device for 1-6-12 lead ECG data acquisition and a method of working thereof. The method of monitoring cardiac health condition of a patient comprises of receiving, by a cardiac monitoring device, an electrocardiograph (ECG) input data signals from at least two electrodes attached to the patient, performing, a quality check on acquiring the ECG input data signals, processing the acquired ECG input data signals, encrypting the processed ECG input data signals and transmitting the encrypted ECG signals to one or more external user devices over a wireless communication interface. The acquiring the ECG input data signals comprises of integrating a closed loop Right Leg Drive (RLD) as a shield drive and a cable/electrode shield to reduce noise coupling to the ECG input data signals.