The electrocardiogram (EKG) is one of the major Para-clinic exams for evaluating patients suspected to cardiac or non-cardiac disease which could be very informative especially when assessed by experienced clinicians. To improve and accelerate the approach to EKG interpretation, simple and accurate criteria are useful and save the physician's time especially in emergent situations. In this article, we introduce our criteria which determine whether the electrical axis of heart is normal or not and if abnormal, what kind of deviation it has. These criteria say that "if the mean QRS complex in leads I and II are positive, the axis will be accu-rately in the normal range (-30 to +90); unless, the axis is abnormal necessitating a more complex evaluation". These criteria could simplify the first step of the approach to EKG interpretation especially in emergent situations. They can also be proper substitute for current methods of heart axis determination in clinical practice and for educational goals. Â© 2010 Motaharsadat Hosseini et al

Hoseini, S.S.

Hosseini, M.

Shoar, N.

Shoar, S.

kashan university of medical sciences

Iranian Journal of 
Medical Hypotheses and Ideas 
                                  
 
 
 
 
ONE-TWO Criteria: Improving the Approach to Electrocardiogram 
 
Motaharsadat Hosseini1, Sayed Shahabuddin Hoseini2, Nasrin Shoar3 and Saeed Shoar4 
 
1Department of pharmacology, School of medicine, Isfahan University of medical sciences, Isfahan, Iran 
2Department of pharmacology, Tehran University of medical sciences,Tehran, Iran 
3Department of cardiology, Kashan university of medical sciences, Kashan, Iran 
4Department of pharmacology, Tehran University of medical sciences, Tehran, Iran 
 
 
Corresponding author: 
Saeed Shoar  
Department of pharmacology /Tehran University of medical sciences/Tehran/ Iran 
Address: Number 54-Qods dormitory- Qods street- Tehran- Iran 
Phone: +98-913-362-0932 
E-mail: ssht84@yahoo.com  
 
 
Received:  30 Aug 2009 
Accepted:  20 Dec 2009 
Published: 13 Jan 2010 
Irn J  Med Hypotheses Ideas, 2010, 4:1 
 
© 2010 Motaharsadat Hosseini et al.; licensee Tehran Univ. Med. Sci. 
 
 
Abstract 
The electrocardiogram (EKG) is one of the major Para-clinic exams for evaluating 
patients suspected to cardiac or non-cardiac disease which could be very informative 
especially when assessed by experienced clinicians. To improve and accelerate the 
approach to EKG interpretation, simple and accurate criteria are useful and save the 
physician’s time especially in emergent situations. 
In this article, we introduce our criteria which determine whether the electrical axis of 
heart is normal or not and if abnormal, what kind of deviation it has. These criteria 
say that "if the mean QRS complex in leads I and II are positive, the axis will be accu-
rately in the normal range (-30 to +90); unless, the axis is abnormal necessitating a 
more complex evaluation". These criteria could simplify the first step of the approach 
to EKG interpretation especially in emergent situations. They can also be proper 
substitute for current methods of heart axis determination in clinical practice and for 
educational goals. 
 
Keywords 
Heat axis, Electrocardiogram, Criteria, Heart leads 
 
 
 
Introduction 
 
Recording electrical activity of heart as EKG and 
its interpretation is one of the first    approaches to a 
patient with cardiovascular disorder.  Interpretation 
of EKG can begin with determination of heart axis. 
This action not only makes an image of the heart 
anatomical structure, but also helps to detect some 
of the cardiac functional abnormality (1). Available 
methods of heart axis determination help to calcu-
late the heart axis and make a differentiation be-
tween normal and abnormal ones. But these methods 
 Original article 
 
 
  
Motaharsadat Hosseini et al. Irn J Med Hypotheses Ideas 2010, 4:1 
 
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are not definitely accurate, leading to false results in 
some cases. 
 The normal range of heart axis is between -30 to 
+90 degree and an axis more negative than -30 
degree is referred to as left axis deviation(2).The 
current methods (using I and aVF(3) or I and III) 
can only determine that the axis is between 0 and 
+90 or not; But in some cases that the axis is be-
tween 0 and -30 degree, a more complete attention is 
needed, because the axis is normal but is not 
matched with the normal range of these methods. 
An example of such cases is shown in figure 1. In 
this figure, the mean QRS complex is positive in I 
and negative in aVF, suggesting a left axis devia-
tion; but in fact, the axis is normal locating between 
0 and -30 degree. 
     In this article, we developed novel ONE-TWO 
criteria, which solve this problem and determine the 
normal axis (between -30 to +90 degree) that is 
accurately matched with the normal range men-
tioned in related text books. 
 
Hypotheses 
 
   The electrocardiogram is a recording of cardiac 
electrical activity by skin electrodes. Although the 
technique is easy and fast, its pattern should be 
interpreted to solve many problems and clarify lots 
of important clinical conditions. The EKG is indi-
cated for detection of cardiac arrhythmias, myocar-
dial infarction, hyperkalemia, hypokalemia, bundle 
branch block, ischemic heart disease, stress test, 
pulmonary embolism and hypothermia (4). When 
being read and interpreted by a highly skilled and 
experienced physician, an EKG is considered one of 
the most useful records of heart function. The first 
approach to EKG is determination of the heart axis.     
   The normal heart axis ranges from -30 to +90 
degree. An axis more negative than -30 degree is 
defined as left axis deviation and an axis more 
positive than +90 degree is referred to as right axis 
deviation (5). Some of the most common cases that 
may be associated with the axis deviation are sum-
marized in table 1 (6). 
   The heart axis is determined using the mean 
QRS in two heart leads, mostly I and aVF (7, 8) or I 
and III (4, 7). To determine the axis of total QRS, 
we draw perpendicular lines from the apices of two 
leads (e.g. I and III). The point of intersection of 
these two perpendicular lines represents the apex of 
the mean QRS axis in ventricles. The point of 
intersection of two leads is the negative end of the 
QRS axis. Therefore, the mean QRS axis is drawn 
between these two points. 
 The aforementioned method is summarized as 
following: 
1) Plot the net deflection of QRS complex (mean 
QRS) for both leads I and aVF along each lead. 
According to the sum of deflection, plot toward the 
positive or negative pole of  the relevant lead; 
 
 2) Run perpendicular lines from each of the plot-
ted points for these two leads; 
 3) The point of intersection of perpendicular 
lines represents the apex of the mean QRS axis in 
ventricles; 
 4) Draw a vector from the intersection of leads I 
and II and the intersection of the perpendicular lines 
(vector tip). The angel between the vector and the 
lead I is heart  
 
Electrical axis angel 
 
  The average electrical potential generated by the 
ventricles during depolarization is represented by 
the length of this axis (7). Positive QRS complexes 
in leads I and aVF suggest an axis between 0 and 90 
degree(4), but if the QRS complex is negative in 
aVF and positive in I, then determining the normal 
axis will face a problem because it is not clear that 
the axis is less or more than -30 degrees. 
 For example, figure 1 shows an EKG in which 
the mean QRS complexes in leads aVF and I are 
negative and positive, respectively. In this case, 
determination of this fact that the heart axis is in the 
normal range or there is a left deviation is difficult 
and even impossible without using exact geometric 
methods, and here is where a need for exact and fast 
criteria is sensed. 
  We have developed novel criteria that not only 
solve the aforementioned problem, but also have 
other benefits. The criteria which are called ONE-
TWO, uses the mean QRS complex in leads I and II 
which is defined as below: " if the mean QRS 
complexes in leads I and II are positive, the axis will 
be accurately in the normal range (-30 to 90 de-
grees); unless, the axis is abnormal necessitating a 
more complete evaluation. 
  In abnormal cases, we have two conditions: 
 If QRSI> QRSII, then it is left axis deviation 
 If QRSII> QRSI, then it is right axis deviation.” 
The criteria are originated from these two facts: 
If the mean QRS complex is positive in lead I, the 
axis ranges between -90 to +90 degrees. 
If the mean QRS complex is positive in lead II, the 
axis rang is between -30 to +120 degrees. 
    Merging these two points conclude axis range 
between -30 to +90 which is matched with the 
normal axis of heart (figure 2). 
   Each electrocardiogram that fulfills these crite-
ria has normal axis and each one that has normal 
axis fulfills these criteria. We think that using these 
criteria is easy and fast (important especially in 
emergent conditions) and could be an appropriate 
substitute for current methods of heart axis determi-
nation (I and aVF or I and III) for educational goals. 
                                                        
Evaluation of the hypotheses 
 
 This method can be assessed clinically by com-
paring the EKG of patients in normal and abnormal 
ranges of heart axis with other practical tests like 
Motaharsadat Hosseini et al. Irn J Med Hypotheses Ideas 2010, 4:1 
 
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echocardiography, exercise test, and if indicated 
angiography. We should choose two groups of 
individuals; the first group consists of persons with 
abnormal cardiac electrical axis (less than -30 or 
more than +90) and the second one contains persons 
with normal axis. These two groups should be 
matched for age, sex, ethnicity, etc. Then, they 
should be evaluated for cardiac and non-cardiac 
diseases, performing more exact paraclinical studies 
such as angiography of heart vessels, exercise test, 
heart perfusion scan, echocardiography and nuclear 
imaging.  By analyzing the data using ANOVA and 
Student t-test, it will be evident that how a normal 
range of EKG can conclude the absence of cardiac 
disorders, and how an abnormal one can predict the 
presence of such diseases in the heart. 
  Results of such study, if confirms efficacy of 
these criteria will be useful in fields of emergency 
medicine, education, and following up of patients 
for heart disease. 
 
Discussion 
 
The main investigatory techniques in cardiovas-
cular disorders are EKG, chest x ray, echocardio-
graphy, etc (9). Interpretation of signs and symp-
toms of patients, making differential diagnosis and 
thus treating them should be fast and without any 
time wasting. This fact is more evident in the emer-
gent condition especially in old patients with cardi-
ovascular disorders. So, the clinicians should do 
their best to avoid time wasting to improve the 
patient's conditions. Every minute that heart contin-
ues to fibrillate (for example, after a heart attack), 
the chance of heart rhythm recovery decreases by 
about 10% (10, 11).  
  Because ONE-TWO criteria are exact, fast and 
easy in axis determination and differentiation 
between the normal axis and the abnormal ones, 
they could simplify the approach to EKG in emer-
gent conditions. Besides, these criteria are easy to be 
used by the health care staffs who may not be expert 
in interpreting EKG. Because these criteria could 
simply determine whether the axis is normal or not, 
they could be used as useful and practical general 
screening criteria for some cardiac and non-cardiac 
diseases. Avoiding of time wasting in advanced 
cardiac life support(ACLS) and having appropriate 
features to be included in heart axis issues in related 
textbooks are some other benefits. 
 
Conclusion 
 
 Eventually, we recommend using these criteria 
as faster, easier, and more accurate approach in the 
first step of going to the EKG interpretation. It can 
be used in emergency settings and for rapid initial 
evaluation of one's EKG; being abnormal, other 
accurate diagnostic tests should be performed to 
detect or confirm exact diagnosis. For example, a 55 
years old lady who is admitted to the orthopedic 
surgery ward with femoral neck fracture 7 days ago 
is now complaining of sudden onset dyspnea. The 
night shift resident visits the patient and after order-
ing the EKG, he finds positive QRS in leads aVF 
and negative one in lead I; the right axis deviation is 
confirmed. Being suggested for acute pulmonary 
emboli, chest CT angiography is ordered. Consider-
ing this hypothesis in educational fields can have 
important application for training electrophysiology, 
because it is easy and reliable.  
 
Acknowledgment 
 
  We wish to thank Professor A. Dehpour from 
department of pharmacology/ Tehran University of 
medical sciences for reviewing the manuscript. 
 
 
 
Overview Box 
 
 
 
What do we already know about the subject?  
Determination of heart electrical axis was always limited to methods which ignored some errors, and we 
just bring out a concept as new criteria.  
 
What does your proposed theory add to the current knowledge available, and what benefits does it 
have?  
This hypothetic paper expresses a new approach to heart axis determination using another leads among the 
previous ones. We discovered accurate criteria which is easy and fast for determination of heart electrical 
axis. 
  
Among numerous available studies, what special further study do you propose for testing the idea?  
We recommend performing a case-control study to assess the hypotheses. Two groups of individuals 
(having normal versus abnormal heart axis according to new criteria) should be evaluated for cardiac and 
non-cardiac diseases. The results should be assessed statistically. This will verify the efficacy of the 
criteria. 
Motaharsadat Hosseini et al. Irn J Med Hypotheses Ideas 2010, 4:1 
 
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Table 1. The major causes for deviation of heart axis 
 
Right axis deviation Left axis deviation 
Right ventricular overload 
Left posterior fascicular block 
Lateral wall MI 
Left ventricular dextrocrdia 
Left side pneumothorax 
Left ventricular hypertrophy  
Block in the anterior fascicle of The left bundle system 
Inferior wall MI 
 
 
 
Figure 1. An example of a little complicated EKG in heart axis determination (1) 
 
 
 
 
 
 
 
Figure 2. Determination of normal range of Heart axis 
↓ 
Motaharsadat Hosseini et al. Irn J Med Hypotheses Ideas 2010, 4:1 
 
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4. Litwin SH. Diagnostic Tests and Procedures in the Patient with Cardiovascular Disease. In Carpenter CCJ (ed): Andreoli 
and Carpenter’s Cecil Essentials of Medicine, 7th ed. Philadelphia, Saunders Elsevier, 2007, pp 52,53. 
5. Mirvis DM, Goldberger AL. Electrocardiography. In Braunwald E (ed): Heart disease, 6th ed. Philadelphia, W.B.Saunders 
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6. Braunwald E. Disorders of the cardiovascular system: In Kasper ennis L. (ed): Harrison's principles of internal medicine, 
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7. The normal electrocardiogram. In Guyton AC, Hall JE (ed) Textbook of medical physiology, 11th ed. Philadelphia, Elsevier 
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ONE-TWO criteria: Improving the approach to electrocardiogram

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ONE-TWO criteria: Improving the approach to electrocardiogram

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