a total of 85 ( 30 women 55 men ) consecutive patients routinely referred to coronary angiography for stable angina pectoris were included in the study after the following exclusions : any kind of rhythm abnormailities that could have interfered with p- wave analysis ( af , freguent atrial and ventriculer beats , pacemaker rhythm ) , acute coronary syndromes , valvular heart disease , serum electrolyte disturbances , abnormal thyroid function , pulmonary hypertension , cardiomyopathies , use of any antiarrhythmic drug , history of myocardial infarction , percutaneus coronary intervention , and cardiac surgery .
entry criteria included chest pain or other symptoms suggestive of myocardial ischemia whc clinically indicated coronary angiography .
the clinical risk factors for the patients such as age , gender , hypertension ( ht ) , diabetes mellitus ( dm ) , history of hyperlipidemia , and smoking status were noted .
patients were divided into 4 groups based on their extent of angiographic coronary artery disease .
patients with normal coronary arteries were labeled as normal group ( 25 patients ) , 22 patients with signficant obstruction in 1 major epicardial artery were considered as having 1 vessel disease , 26 patients with significant obstruction in 2 major epicardial arteries were included in the 2 vessel disease group , finally 12 patients with significant obstruction in 3 major epicardial arteries were enrolled in the 3 vessel disease group .
hypertension was defined based on blood pressure 140/90 mm hg or greater , and a history of antihypertensive drug use .
dm was defined as fasting blood glucose126 mg / dl on two occasions or being on treatment .
all demographic and clinical data were collected prospectively . a 12- lead surface electrocardiogram ( ecg )
recordings were acquired at a paper speed of 50 mm / s , with 1 mv / cm standardization .
two in - vestigators without knowledge of the clinical status of the patients manually measured the maximum and minimum p - wave duration and pd . to improve accuracy we used calipers and magnifying lenses .
the onset of p - wave was defined as the junction between the end of the p - wave deflection and the ofset of the p - wave as the junction between the end of the p - wave deflection and the isoelectric line .
we calculated p maximum ( p max ) and p minimum ( p min ) and their diferences were defined as pd .
echocardiographic measurements were performed by using a 2.5 mhz probe with acuson sequa echocardiographic device ( siemens , usa ) .
lv dimensions were generally measured with 2d - guided m - mode from the parasternal projections , using a leading edge to leading edge convention . the left atrium and
the left ventricle diameters , left ventricular ejection fraction ( lvef ) , and the presence of mitral insufficiency were evaluated .
the angiographic characteristics , which included lesion location and percentage stenosis , of all coronary lesions in the index coronary angiogram were obtained by throughly reviewing the angiogram .
angiographic analysis was carried out by two experienced cardiologists who were blinded to the study protocol .
vessel score was the number of vessels with a significant stenosis ( > % 50 ) .
we also used gensini scoring system . according to this method we defined narrowing of the lumen of coronary arteries as 1 for 1 - 25% stenosis , 2 for 26 - 50% stenosis , 4 for 51 - 75% stenosis , 8 for 76 - 90% stenosis , 16 for 91 - 99% stenosis and 32 for total occlusion .
then the score is multiplied by a factor that shows the significance of the lesion s location .
it is 2.5 for proximal left anterior descending artery ( lad ) and proximal circumflex artery ( cx ) lesions , 1.5 for a mid - lad lesion , and 1 for distal lad , mid / distal cx and right coronary artery lesions .
baseline demographic data are presented as mean  sd for continuous variables and frequancies for discrete variables .
comparison of parametric values between the 2 groups was performed by means of an independent samples t - test .
correlation between p wave measurements and angiographic , clinical , and echocardiographic variables were assessed by pearson correlation coefficient . to ascertain the independent contribution to pd multiple linear regression analysis
a total of 85 ( 30 women 55 men ) consecutive patients routinely referred to coronary angiography for stable angina pectoris were included in the study after the following exclusions : any kind of rhythm abnormailities that could have interfered with p- wave analysis ( af , freguent atrial and ventriculer beats , pacemaker rhythm ) , acute coronary syndromes , valvular heart disease , serum electrolyte disturbances , abnormal thyroid function , pulmonary hypertension , cardiomyopathies , use of any antiarrhythmic drug , history of myocardial infarction , percutaneus coronary intervention , and cardiac surgery .
entry criteria included chest pain or other symptoms suggestive of myocardial ischemia whc clinically indicated coronary angiography .
the clinical risk factors for the patients such as age , gender , hypertension ( ht ) , diabetes mellitus ( dm ) , history of hyperlipidemia , and smoking status were noted .
patients were divided into 4 groups based on their extent of angiographic coronary artery disease .
patients with normal coronary arteries were labeled as normal group ( 25 patients ) , 22 patients with signficant obstruction in 1 major epicardial artery were considered as having 1 vessel disease , 26 patients with significant obstruction in 2 major epicardial arteries were included in the 2 vessel disease group , finally 12 patients with significant obstruction in 3 major epicardial arteries were enrolled in the 3 vessel disease group .
hypertension was defined based on blood pressure 140/90 mm hg or greater , and a history of antihypertensive drug use .
dm was defined as fasting blood glucose126 mg / dl on two occasions or being on treatment .
a 12- lead surface electrocardiogram ( ecg ) was obtained from each patient while in supine position .
recordings were acquired at a paper speed of 50 mm / s , with 1 mv / cm standardization .
two in - vestigators without knowledge of the clinical status of the patients manually measured the maximum and minimum p - wave duration and pd . to improve accuracy we used calipers and magnifying lenses .
the onset of p - wave was defined as the junction between the end of the p - wave deflection and the ofset of the p - wave as the junction between the end of the p - wave deflection and the isoelectric line .
we calculated p maximum ( p max ) and p minimum ( p min ) and their diferences were defined as pd .
echocardiographic measurements were performed by using a 2.5 mhz probe with acuson sequa echocardiographic device ( siemens , usa ) .
lv dimensions were generally measured with 2d - guided m - mode from the parasternal projections , using a leading edge to leading edge convention . the left atrium and
the left ventricle diameters , left ventricular ejection fraction ( lvef ) , and the presence of mitral insufficiency were evaluated .
the angiographic characteristics , which included lesion location and percentage stenosis , of all coronary lesions in the index coronary angiogram were obtained by throughly reviewing the angiogram .
angiographic analysis was carried out by two experienced cardiologists who were blinded to the study protocol .
vessel score was the number of vessels with a significant stenosis ( > % 50 ) .
we also used gensini scoring system . according to this method we defined narrowing of the lumen of coronary arteries as 1 for 1 - 25% stenosis , 2 for 26 - 50% stenosis , 4 for 51 - 75% stenosis , 8 for 76 - 90% stenosis , 16 for 91 - 99% stenosis and 32 for total occlusion .
then the score is multiplied by a factor that shows the significance of the lesion s location .
it is 2.5 for proximal left anterior descending artery ( lad ) and proximal circumflex artery ( cx ) lesions , 1.5 for a mid - lad lesion , and 1 for distal lad , mid / distal cx and right coronary artery lesions .
baseline demographic data are presented as mean  sd for continuous variables and frequancies for discrete variables .
comparison of parametric values between the 2 groups was performed by means of an independent samples t - test .
correlation between p wave measurements and angiographic , clinical , and echocardiographic variables were assessed by pearson correlation coefficient . to ascertain the independent contribution to pd multiple linear regression analysis
the clinical , echocardiographical and electrocardiographic characteristics of the cases in group 1 and group 2 are shown in table 1 .
there was no difference in comparison of groups with regard to age , hypertension , diabetes and smoking .
although p max was significantly higher in groups 2 , 3 and 4 , no difference was determined between groups 1 and 2 .
the relationship between pd , and clinical , and echocardiographic characteristics in patients with cad is shown in table 3 . in cad group ,
pd was related to diabetes , smoking and ef ( p=0.014 , p=0.006 , p=0.003 ) but not related to other clinical and echocardiographic characteristics ( table 3 ) .
pmax and pd were related to vessel and gensini scores in patients with cad ( table 4 ) . in multivariate
logistic regression analysis , increased pd was found to be independently associated with vessel ( =4.139 , p=0.002 ) and gensini score ( =0.132 , p=0.007 ) .
baseline clinical , echocardiographical and electrocardiographic characteristics of the study population cad : coronary artery disease ; lv : left ventricle ; edd : end - diastolic dimension ; esd : end - systolic dimension ; ef : ejection fraction ; lad : left atrial diameter ; p max : p maximum ; p min : p minimum ; pd : p dispersion ; ns : non - significant . comparison of p wave measurements of the groups according to vessel score p1 : comparision of variables between group 1 and 2 ; p2 : comparision of variables between group 2 and 3 ; p3 : comparision of variables between group 2 and 4 ; p max : p maximum ; p min : p minimum ; pd : p dispersion . the relationship between p wave dispersion , and clinical and echocardiographic characteristics in patients with coronary artery disease lv : left ventricle ; edd : end - diastolic dimension ; esd : end - systolic dimension ; ef : ejection fraction ; lad : left atrial diameter ; mr : mitral regurgitation the relationship between p wave measurements and gensini and vessel scores in patients with coronary artery disease p max : p maximum ; p min : p minimum ; pd : p wave dispersion
our study showed , increased p wave duration and pd was related to the extent and severity of cad in stable coronary artery disease patients . similarly , increased pd has been observed to be associated with coronary artery disease severity .
af is the most common cardiac rhythm abnormality and its incidence was 0.6% in the coronary artery surgery study ( cass ) registry .
interatrial conduction delays have been shown to be implicated in initiating and maintaining af [ 13 - 15 ] .
another mechanism for increased pd may be the increase in collagen fiber deposition in the cardiac interstitium .
it was reported that pd was associated with inhomogeneus and discontinuous propogation of sinus impulses .
electrocardiographic markers of abnormal atrial conduction , such as pd , p maximum , and p minumum , may be influenced by myocardial ischemia .
previous studies have demonstrated that atrial ischemia is implicated in the pathogenesis of af [ 21 , 22 ] .
dilaveris et al . reported that myocardial ischemia prolongs pd in 95 patients with documented cad and zmen et al .
in addition , it has been shown that p - wave dispersion is increased in coronary slow- flow phenomenon .
ischemia- induced inhomogeneous and discontinuous atrial conduction may be related to increased p maximum and pd .
reduced blood flow due to coronary atherosclerosis may contribute to the development of tissue injury and fibrosis .
another explanation for this is that ischemia causes renin angiotensin system activation [ 28 , 29 ]
. the regional fibrosis in the atrial wall , due to chronic ischemia could cause different atrial conductions leading to increased pd in surface ecgs .
another pathophysiological explanation for increased p - wave duration and dispersion in cad may be autonomic tone associated with cad .
ischemic left ventriculer dysfunction may increase left atrial pressure , and might another fundamental causes of increased p wave duration and pd in patients with cad compared to control subjects .
atrial strain , which is a sugnificant factor in the pathophysiology of af together with ischemia- induced hetergeneous atrial conduction , may results an increase in p wave duration and pd .
similarly , in our study there was no significant association between p min and gensini and vessel scores .
the major limitation of our study is the small number of patients included in the study . for evaluation of ecg results we did not use the high - resolution computer software program .
previous studies have found a low error of the measurement of pd on paper printed ecgs , contrarily other studies reported that manual pd measurement on paper printed ecgs obtained at a standard signal size may effect the accuracy and reproducibility of the results . in conclusion ,
our results suggest that there is a considerable association between increased pd and the severity of cad .
 objective : p- wave dispersion ( pd ) is an indicator of inhomogeneous and discontinuous propagation of sinus impulses . in the present study we aimed to investigate the pd and its association with the severity of the disease . in patients with stable coronary artery disease.methods:we prospectively analyzed 60 subjects with coronary artery disease ( cad ) and 25 subjects with nor - mal coronary angiograms ( control group ) . 
 the maximum and minimum p - wave duration and pd were measured from the 12-lead surface electrocardiograms . 
 the cad severity was assessed by the severity score ( gensini score ) and the number of vessels involved ( vessel score).results : p max was longer in cad group compared with the control group ( p<0.001 ) . 
 pd was greater in the cad group , compared with the control group ( p<0.001 ) . 
 however , p min did not differ between the two groups . 
 in bi - variate correlation , increased pd was correlated with presence of diabetes mellitus ( r=0.316 , p=0.014 ) , smoking ( r=0.348 , p=0.006 ) , left ventricular ejection fraction ( r=-0.372 , p=0.003 ) , vessel score ( r=0.848 , p=0.001 ) , and gensini score ( r=0.825 , p=0.001 ) . 
 multiple linear regression analysis showed that pd was independently associated with vessel score ( ( 3=0.139 , p=0.002 ) and gensini score ( ( 3=0.132 , p=0.007).conclusion : pd was greater in patients with cad than in controls and it was associated with cad severity . 
MATERIALS AND METHODS
Study population
Electrocardiography
Echocardiographic measurement
Coronary Angiography
Statistical analyses
RESULTS
DISCUSSION