Heart rate calculator with reduced overcounting

A wearable cardioverter defibrillator (WCD) system, comprising:

• a support structure configured to be worn by a patient;
• an energy storage module configured to store an electrical charge;
• a discharge circuit coupled to the energy storage module;
• one or more sensors configured to sense an Electrocardiogram (ECG) signal of the patient while the patient is wearing the support structure;
• and
• a processor having a memory, wherein the memory is configured with:
• classification criteria to classify the ECG signal into one of a plurality of ECG rhythm types, and
• for each of the plurality of ECG rhythm types, a corresponding set of operations to determine a heart rate of the patient, wherein each set of the corresponding sets of operations is different from every other set of the corresponding sets of operations,
• wherein the processor is configured to:
• receive the ECG signal from the one or more sensors,
• analyze the received ECG signal, using the classification criteria, to identify an ECG rhythm type of the plurality of ECG rhythm types into which the received ECG signal is classified, wherein, to identify the ECG rhythm type, the processor is configured to:
• apply a first margin of one or more margins to a combination of even measured intervals using a first operator, and a second margin of the one or more margins to a combination of odd measured intervals using a second operator, wherein the combination of even measured intervals and the combination of odd measured intervals are obtained from the received ECG signal, and
• after the application, compare the combination of even measured intervals to the combination of odd measured intervals to identify the ECG rhythm type, and
• determine the heart rate of the patient using the set of operations corresponding to the identified ECG rhythm type.