3 Nehb Precordial Leads Anterior, Dorsalis and Inferior Allow Accurate Diagnostics of Different Heart Conditions

The method of ECG recording with the use of three bipolar leads A (anterior), D dorsalis) and J (or I - inferior) was introduced in 1938 by German electrophysiologist W. Nehb. Being positioned on the chest in the immediate proximity to the heart, and being aligned to the anatomic position of the heart, these leads are very sensitive and allow accurate diagnostics of different heart conditions. All the active leads are placed on anterolateral plane of the chest wall requiring little anatomical window making this technique convenient for express diagnostics using compact electrocardiographic devices without any loss of valuable information.

Active electrodes are located on the chest in the following order: 1st- red standard electrode placed in the second intercostal space to the right from sternum corresponding to V1 for standard 12-lead ECG recording, 2nd- green standard lead placed in the position corresponding to V4; 3rd- yellow in the position V7. Then ECG recorded as if in the I standard lead would be defined as Nehb's D, which records the potential on the posterior left ventricle wall; II standard lead would produce Nehb's A which corresponds to the potential on the anterior wall of the left ventricle, and III standard lead would record Nehb's J, which reflects the potential on the diaphragmatic surface of heart.

Been simple and informative, this ECG recording modality may be applicable for usage with compact portable cardiographer devices for express diagnosis in different situations and may allow faster and more adequate outpatient response in the case of emergencies.

Nehb 3 leads ECG can provide the clinician with portable, reliable, comprehensive and constant ECG monitoring and by this facilitate rapid diagnosis and treatment of STEMI.

General Objective: to compare the diagnostic ability of Nehb 3 lead ECG and standard 12 lead ECG in patients presenting to EMS with STEMI.

Inclusion criteria:

Age ≥ 18 years ST elevation in more than 2 contiguous leads (\> 1 mV in limb leads \& V5-V6; more than 2 mm in V1-V4) Complains of chest, neck, jaw, arm, epigastric or back pain or dyspnea Patients directly transferred to the coronary care unit.

Exclusion criteria:

Unconscious patients Unwillingness to participate in the study Presence of LBBB

Protocol:

100 patients with STEMI will be included. After initial 12 leads ECG made by EMS personnel will show changes consistent with STEMI, a portable Nehb 3 leads (ECG MiniMonitor CG 5000 N) recorder will be connected to the patient. 12 leads ECG recording will be performed according to the EMS and the CCU practices, i.e: before transport, on admission, before and after reperfusion therapy (thrombolysis or PCI), during angina episodes, and every 24 hours since admission. Nehb tracing will be recorded in parallel with standard 12 leads ECG.

ECG findings of standard 12 leads ECG and Nehb 3 leads ECG will be compared for:

Presence of ST elevation (defined as presence of ST segment elevation in 2 or more contiguous leads in 12 leads ECG versus presence of ST segment elevation or depression in 1 or more leads in Nehb ECG).

Area at risk \[8\] (defined as sum of amplitudes of ST segment elevations of all leads that demonstrate this in 12 leads ECG versus sum of amplitudes of ST segment elevations of all leads in Nehb ECG)

Severity of ischemia \[8\] (defined as disappearance of S waves in leads with normally negative QRS or J point elevation over more than 50% of R wave height in leads with normally positive QRS in 12 leads versus Nehb ECG)

Time discrimination (defined as presence of ST segment elevation at any time of recording and total amount of such events by 12 leads ECG versus Nehb ECG).

Eligibility Criteria:
Inclusion criteria:

1. Age ≥ 18 years
2. ST elevation in more than 2 contiguous leads (\> 1 mV in limb leads \& V5-V6; more than 2 mm in V1-V4)
3. Complains of chest, neck, jaw, arm, epigastric or back pain or dyspnea
4. Patients directly transferred to the coronary care unit.

Exclusion criteria:

1. Unconscious patients
2. Unwillingness to participate in the study
3. Presence of LBBB