diff --git a/CHANGELOG.md b/CHANGELOG.md
index b0af83b..8d0a917 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,11 @@
+## [1.7.1] - 27.06.2022.
+
+* Add raw keys for electrocardiogram classification and symptom status
+
+## [1.7.0] - 23.06.2022.
+
+* Make `averageHeartRate` optional as a `HKElectrocardiogram.Classification.inconclusivePoorReading` may not have a value for this field
+
 ## [1.6.9] - 27.05.2022.
 
 * Add copyWith methods to Correlation
diff --git a/HealthKitReporter.podspec b/HealthKitReporter.podspec
index 8f45bc9..0292190 100644
--- a/HealthKitReporter.podspec
+++ b/HealthKitReporter.podspec
@@ -8,7 +8,7 @@
 
 Pod::Spec.new do |s|
   s.name                  = 'HealthKitReporter'
-  s.version               = '1.6.9'
+  s.version               = '1.7.1'
   s.summary               = 'HealthKitReporter. A wrapper for HealthKit framework.'
   s.swift_versions        = '5.3'
   s.description           = 'Helps to write or read data from Apple Health via HealthKit framework.'
diff --git a/Package.swift b/Package.swift
index 83e9573..ccda14d 100644
--- a/Package.swift
+++ b/Package.swift
@@ -1,4 +1,4 @@
-// swift-tools-version:5.2
+// swift-tools-version:5.3
 // The swift-tools-version declares the minimum version of Swift required to build this package.
 
 import PackageDescription
diff --git a/Sources/Decorator/Extensions+HKElectrocardiogram.swift b/Sources/Decorator/Extensions+HKElectrocardiogram.swift
index fe30f4e..477002f 100644
--- a/Sources/Decorator/Extensions+HKElectrocardiogram.swift
+++ b/Sources/Decorator/Extensions+HKElectrocardiogram.swift
@@ -13,13 +13,8 @@ extension HKElectrocardiogram {
 
     func harmonize(voltageMeasurements: [Electrocardiogram.VoltageMeasurement]) throws -> Harmonized {
         let averageHeartRateUnit = HKUnit.count().unitDivided(by: HKUnit.minute())
-        guard
-            let averageHeartRate = averageHeartRate?.doubleValue(for: averageHeartRateUnit)
-        else {
-            throw HealthKitError.invalidValue(
-                "Invalid averageHeartRate value for HKElectrocardiogram"
-            )
-        }
+        let averageHeartRate = averageHeartRate?.doubleValue(for: averageHeartRateUnit)
+        
         let samplingFrequencyUnit = HKUnit.hertz()
         guard
             let samplingFrequency = samplingFrequency?.doubleValue(for: samplingFrequencyUnit)
@@ -34,7 +29,9 @@ extension HKElectrocardiogram {
             samplingFrequency: samplingFrequency,
             samplingFrequencyUnit: samplingFrequencyUnit.unitString,
             classification: classification.description,
+            classificationKey: classification.key,
             symptomsStatus: symptomsStatus.description,
+            symptomsStatusKey: symptomsStatus.key,
             count: numberOfVoltageMeasurements,
             voltageMeasurements: voltageMeasurements,
             metadata: metadata?.compactMapValues { String(describing: $0 )}
@@ -62,6 +59,29 @@ extension HKElectrocardiogram.VoltageMeasurement: Harmonizable {
 // MARK: - CustomStringConvertible
 @available(iOS 14.0, *)
 extension HKElectrocardiogram.Classification: CustomStringConvertible {
+    public var key: String {
+        switch self {
+        case .notSet:
+            return "notSet"
+        case .sinusRhythm:
+            return "sinusRhythm"
+        case .atrialFibrillation:
+            return "atrialFibrillation"
+        case .inconclusiveLowHeartRate:
+            return "inconclusiveLowHeartRate"
+        case .inconclusiveHighHeartRate:
+            return "inconclusiveHighHeartRate"
+        case .inconclusivePoorReading:
+            return "inconclusivePoorReading"
+        case .inconclusiveOther:
+            return "inconclusiveOther"
+        case .unrecognized:
+            return "unrecognized"
+        @unknown default:
+            fatalError()
+        }
+    }
+    
     public var description: String {
         switch self {
         case .notSet:
@@ -88,6 +108,18 @@ extension HKElectrocardiogram.Classification: CustomStringConvertible {
 // MARK: - CustomStringConvertible
 @available(iOS 14.0, *)
 extension HKElectrocardiogram.SymptomsStatus: CustomStringConvertible {
+    public var key: String {
+        switch self {
+        case .notSet:
+            return "notSet"
+        case .none:
+            return "none"
+        case .present:
+            return "present"
+        @unknown default:
+            fatalError()
+        }
+    }
     public var description: String {
         switch self {
         case .notSet:
diff --git a/Sources/Model/Payload/Electrocardiogram.swift b/Sources/Model/Payload/Electrocardiogram.swift
index f5ed6b9..b1ce324 100644
--- a/Sources/Model/Payload/Electrocardiogram.swift
+++ b/Sources/Model/Payload/Electrocardiogram.swift
@@ -10,23 +10,27 @@ import HealthKit
 @available(iOS 14.0, *)
 public struct Electrocardiogram: Identifiable, Sample {
     public struct Harmonized: Codable {
-        public let averageHeartRate: Double
+        public let averageHeartRate: Double?
         public let averageHeartRateUnit: String
         public let samplingFrequency: Double
         public let samplingFrequencyUnit: String
         public let classification: String
+        public let classificationKey: String
         public let symptomsStatus: String
+        public let symptomsStatusKey: String
         public let count: Int
         public let voltageMeasurements: [VoltageMeasurement]
         public let metadata: [String: String]?
 
         init(
-            averageHeartRate: Double,
+            averageHeartRate: Double?,
             averageHeartRateUnit: String,
             samplingFrequency: Double,
             samplingFrequencyUnit: String,
             classification: String,
+            classificationKey: String,
             symptomsStatus: String,
+            symptomsStatusKey: String,
             count: Int,
             voltageMeasurements: [VoltageMeasurement],
             metadata: [String: String]?
@@ -36,7 +40,9 @@ public struct Electrocardiogram: Identifiable, Sample {
             self.samplingFrequency = samplingFrequency
             self.samplingFrequencyUnit = samplingFrequencyUnit
             self.classification = classification
+            self.classificationKey = classificationKey
             self.symptomsStatus = symptomsStatus
+            self.symptomsStatusKey = symptomsStatusKey
             self.count = count
             self.voltageMeasurements = voltageMeasurements
             self.metadata = metadata
@@ -117,7 +123,9 @@ extension Electrocardiogram.Harmonized: Payload {
             let samplingFrequency = dictionary["samplingFrequency"] as? NSNumber,
             let samplingFrequencyUnit = dictionary["samplingFrequencyUnit"] as? String,
             let classification = dictionary["classification"] as? String,
+            let classificationKey = dictionary["classificationKey"] as? String,
             let symptomsStatus = dictionary["symptomsStatus"] as? String,
+            let symptomsStatusKey = dictionary["symptomsStatusKey"] as? String,
             let count = dictionary["count"] as? Int
         else {
             throw HealthKitError.invalidValue("Invalid dictionary: \(dictionary)")
@@ -130,7 +138,9 @@ extension Electrocardiogram.Harmonized: Payload {
             samplingFrequency: Double(truncating: samplingFrequency),
             samplingFrequencyUnit: samplingFrequencyUnit,
             classification: classification,
+            classificationKey: classificationKey,
             symptomsStatus: symptomsStatus,
+            symptomsStatusKey: symptomsStatusKey,
             count: count,
             voltageMeasurements: voltageMeasurements != nil
                 ? try Electrocardiogram.VoltageMeasurement.collect(from: voltageMeasurements!)