For the hypertensive patient, various ECG/EKG diagnotic criteria exist (e.g., the scoring or identifying system recommended by Romhilt- Estes score the criteria of Dr. McPhie), sum of tallest precordial R and S waves > 45 mm). ⁹ʹ¹⁰ In a 12 lead ECG recording, evidence of ‘left atrial abnormality’ may occur in the early stages of HTN, and may be associated with LV diastolic dysfunction which could precede abnormalities in the QRS complex. 

          Regard to the QRS amplitude, makeable overlapping exists in normal and hypertensive patients.  Factors such as age, sex, race, and body mass affect the QRS amplitude and may influence the predictive value of the QRS criteria for the diagnosis of LVH.  The ECG/EKG diagnosis of LVH is considerably strengthened in the presence of increased QRS voltages combined with typical repolarization abnormalities (e.g., LV strain pattern). 

     The QRS duration has been documented to widen with increasing severity of hypertension, and the finding of ventricular conduction delay. ¹¹ Also, apparent on the ECG/EKG has been correlated with certain histological abnormalities (e.g., myocardial fibrosis or targeted scar tissue).  In some cases the ECG abnormalities may improve or even revert back to normal with successful anti-hypertensive therapy (decreased QRS voltage and resolution of the ST-T- wave abnormalities). ¹²

     Patients with hypertensive heart disease will typically show signs of LVH and almost always are seen on the ECG recording.  Therefore, when a patient presents with heart failure that is attributed to HTN and other target organ involvement,  he and/or she almost always will have some evidence of LVH on their ECG strip; if not, then other causes for heart failure must be considered. 

Importance of Hyperkalemia –

     The trained technical eye of a nurse and/or nurse practitioner can see an acute (Ac₃) hyperkalemia as it appears on an ECG/EKG recording in peaked T-waves with a narrow base.  The diagnosis of hyperkalemia is almost certain when the duration of the base is 0.20 mm or less (with a rate between 60 and 110 beats per minute). ¹³ As the degree of hyperkalemia increases (K₊ or potassium intoxication), the QRS complex widens, and the electrical axis usually being deviated abnormally to the left and only rarely to the right.  In addition, notice the PR interval prolongation, and the P-wave flattening until it disappears.  If this condition is not detected and assessed by the clinician (RN and/or Physician), and treated in a timely matter, death will ensue either due to “ventricular standstill “or “coarse”, slow ventricular fibrillation.¹⁴  Patient death can also result if the widening QRS complexes occurring at a fast rate are diagnosed as ventricular tachycardia and the patient is not treated with anti-arrhythmic drugs. 

Importance of Hypokalemia -

     Again, in the trained eye of the professional treating clinician, on an ECG recording the abnormality and delayed repolarization that occurs in hypokalemia is best expressed as Q-U- wave rather than through the QT prolongation.  At times on an ECG you will see notching of the T-wave and T- U-wave fusion. ¹⁵  As the serum potassium level falls, the ST segment becomes progressively more depressed and there may be a gradual blending of the T-wave into what appears to be a tall U-wave. 

     Note:  An ECG pattern similar to that of hypokalemia can be produced by some anti-arrhythmic meds, especially quinidine.  Also you should be aware when repolarization is greatly prolonged, ventricular arrhymias, including torsades de pointes (i.e., twisting of the points, a form of ventricular tachycardia nearly always due to medications over-load).  The QRS complexes tend to show a series of complexes, points up followed by complexes, points down.   

24-Hour Ambulatory ECG Holter Monitoring –

     In many academic teaching hospitals and cardiac clinics across the U.S. specially trained registered nurses and nurse practitioner are scanning the results and sending the preliminary reports to the requesting and treating physicians.  It is very important for the clinical investigations using this 24-hour ambulatory ECG monitoring device to be aware of the electrical pathophysiology signs during the scanning period.  In the hypertensive patient it has been shown a greater incidence of ventricular arrhythmias combined with LVH criteria.¹⁶   Ventricular arrhythmias appear to worsen as the hypertrophy (i.e., an increase in size of the heart muscle or any  organ), progresses. 

     Note: For many patients with the added risk factors of HTN + VEN. ARRHYMIAS + HYP. = an increased risk of sudden cardiac death syndrome.  Atrial fibrillation and other supraventricular tachycardias are more common now in patients with hypertension than in the general population findings.¹⁷ 

     As for the general population, that has not been pre-diagnosed for ‘essential hypertension’  the 24-hour ambulatory ECG Holter monitoring device can prove useful in assessing atrial and ventricular arrhythmias in patients with palpitations, near syncope, or syncope episodes. 

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