Comprehensive ECG Guide to Chamber Enlargement and Hypertrophy Diagnosis

Welcome all to the session on Chamber Enlargement.  By the end of this session, you will be able to   identify right atrial abnormality, left  atrial abnormality, left ventricular   hypertrophy and dilatation, and right ventricular  hypertrophy and dilatation, in the ECG. First,  

I would like to tell you the difference  between enlargement and hypertrophy. The term   enlargement is used when there is volume overload  of the ventricle, causing eccentric hypertrophy. That is, there is dilatation of the chamber  of the heart. The term hypertrophy is used  

when there is pressure overload of the  ventricle causing concentric hypertrophy.   That is, there is increase in the thickness  of the myocardial wall. So, we will be using   these terms throughout the session. So, first  we will see about right atrial abnormality.  

So, we all know that the impulses originate in the   SA node. From there, the depolarisation spreads  to the right atrium and to the left atrium. The net vector of this is in this direction  and the normal P wave axis is between  

+30 to +75 degrees. Now, let us see what  happens in a right atrial abnormality.   In right atrial abnormality, there is a stronger  right atrial vector and a normal left atrial   vector. This will cause the P wave axis to shift  clockwise. And in right atrial abnormality,  

the P wave axis will be more than +75 degrees.  In left atrial abnormality, there is a stronger   left atrial vector. This will cause  the P wave axis to shift anticlockwise. And in left atrial abnormality, the P wave access  is less than +30 degree. So, that is the first  

difference. In right atrial abnormality, the P  wave axis will be shifted clockwise, more than   +75 degrees. And in left atrial abnormality,  the P wave axis will be shifted anticlockwise,   that is less than +30 degrees. So, we will see the  morphology of P wave. So, if you remember, in lead  

2, the P wave is having 2 components, the right  atrial component and the left atrial component. The normal amplitude of P wave in lead 2 is  0.25 millivolt, and the duration is less than   0.12 second. In lead 1, the P wave is  having a biphasic shape; the positive  

component contributed by the right atrium,  and the negative component contributed by the   left atrium. The amplitude of each of this  complex is 0.1 millivolt, and the duration is 0.04   second. So, now, let us see what happens in  a right atrial abnormality. So, in lead 2,  

the initial component which is contributed by the  right atrium will be more, will be increased in   amplitude, and the latter component contributed  by the left atrium will remain the same. So, what happens? In lead 2, in right  atrial abnormality, the amplitude of  

the P wave increases; it will be more than 0.25  millivolt; whereas the duration remains the same,   less than 0.12 second. Now, let us see in V1. In  V1, the right atrium, the positive uh component   of the biphasic wave is contributed by the right  atrium. So, that will be increased in amplitude.  

The negative component will remain the same. So,  in V1, in right atrial abnormality, you will see   a tall, a positive deflection  and a small negative deflection. The duration will remain the same. So, to  summarise, in right atrial abnormality,  

we will see tall P wave in both  limb and right precordial leads.   A positive deflection of P wave is seen in lead  V1 or V2, more than 0.15 millivolt. There is   no increase in the total duration of P wave. And  the P wave axis in the frontal plane is more than  

+75 degrees. ECG-1: We will see lead 2 and  V1. We see P wave in lead 2 and V1 because   P wave axis is in the direction of lead  2 and V1 being the right precordial lead. So, here, if you see the lead 2 and V1,  what are we seeing? Here, we have a very  

tall P wave of amplitude more than 4 millimetre.  And in V1 if you see, there is a biphasic P wave   with the positive deflection more than 0.1  millivolt. So, this is an ECG suggestive of   right atrial ar abnormality. There are many  other changes in this ECG, but right now  

we will concentrate on lead 2 and V1. Now,  let us move on to left atrial abnormality. Left atrial abnormality, unlike right atrial  abnormality, it causes interatrial conduction   disturbance, in which the duration of  the middle and the terminal component  

of the P wave is prolonged, owing to delayed left  atrial activation. So, we already discussed about   the P wave axis. There is an anticlockwise shift  in the P wave axis, and the P wave axis will be   less than +30 degrees. Let us see the  morphology of P wave in left atrial abnormality.

So, the initial component in lead 2 which is  contributed by the right atrium remains the same,   whereas the one contributed by the left atrium is  now prolonged. So, how do we, how do we see it in   the ECG? We see a notched P wave in lead 2 with  amplitude remaining the same, but the duration  

more than 0.12 second. And in between these 2  humps, there should be at least one small square.   In lead V1, the positive deflection contributed  by the right atrium remains the same. Whereas, the negative deflection is now deeper and  broader; increases in both amplitude and duration.  

The amplitude will be more than 0.1 millivolt,  and the duration will be more than 0.04 second.   In left atrial abnormality, so, the P wave is  notched with a duration of 0.12 second or more;   this is called as P mitrale; in lead 2, and the 2  humps are separated by at least one small block.  

There is a leftward shift in the P wave axis  in the frontal plane to +15 degrees or beyond. A P terminal force in v lead V1 equal to or  more negative than 0.04 millivolt second. So,   what is P terminal force? It is nothing but  the product of the amplitude and duration of  

the negative component of P wave in V1. So,  we already told, this amplitude and duration,   both are increased in case of left atrial  abnormality. So, this P terminal force   will be more than 0.04 millivolt second in  left atrial abnormality. This is called as  

Morris index. Combined sensitivity of P terminal  force in V1, more than 0.04 millivolt second,   and P wave duration more than 100 millisecond is  much more in diagnosing left atrial abnormality. So, let us see this ECG. Lead 2 and V1,  we can see here. So, what do you see here?  

What do you see here? In lead 2, the P wave is  looking bifid or notched. And if you see carefully   between the 2 humps, there is one small square;  one small square between 2 humps. And in V1,   what are you seeing? There is a positive  component and a negative component which is  

increased in duration, prolonged more than 40  millisecond. So, if you calculate the P terminal   force, it will come more than 0.04 millivolt  second; so, satisfying the Morris index. So, this is an ECG suggestive  of left atrial abnormality.  

So, what happens in a biatrial enlargement?  In case of a biatrial enlargement, uh   both these findings, both the findings of  left atrial abnormality and right atrial   abnormality will be present. That is,  there will be a large diphasic P wave in  

V1, with an initial positive competent more  than 1.5 millimetre, and a terminal negative   component more than 1 millimetre in amplitude  and more than 0.04 second in duration, or both. Or, if there is a tall peaked P wave  in right precordial lead and a wide  

notched P wave in the limb lead or  left recording lead like V5, V6,   that is also suggestive of left biatrial  enlargement. It is called as P tricuspidale. Or,   there will be an increase in both amplitude  and duration of P wave in limb leads.  

So, a combination of findings of right atrial  abnormality and left atrial abnormality are seen   in ECG if there is a biatrial enlargement. So, let  us see this ECG; let us concentrate on lead V1. So, what do you see there? In lead V1, there is  a positive deflection which is well more than  

1 millimetre in amplitude and a negative  deflection of duration more than 40 milliseconds.   So, there are findings of suggestive of both  right atrium and left atrial abnormality. So,   this ECG is suggestive of biatrial enlargement.  So, how will you identify atrial enlargement  

in presence of atrial fibrillation? In atrial  fibrillation, you will not see a P wave; instead,   you will see something called as fibrillatory  waves, which are seen as baseline disturbances. So, you will see something called as  fibrillatory waves and not P waves. So,  

how will you identify atrial enlargement? So, you  see the fibrillatory waves. If there are coarse   fibrillatory waves, that means, the fibrillatory  waves with amplitude more than 1 millimetre,   it is suggestive of an atrial enlargement,  even in presence of atrial fibrillation.  

So, to summarise, in right atrial enlargement,  the amplitude of the P wave is more in lead 2,   and the positive deflection  will be of more amplitude in V1. In left atrial enlargement, there is a notched P  wave in with increased duration in la lead 2 and a  

normal positive deflection and a broader and   deeper negative deflection P wave in V1. A  combination of these findings are seen in   biatrial enlargement. So, now let us move on  to left ventricular hypertrophy and dilatation.  

So, we already told, the impulses originate  from the sinoatrial node. They spread to   the AV node. And from there, right ventricle is  depolarised, then left ventricle is depolarised. The net vector of this will be  in the direction, this direction  

of lead 2, and the normal QRS axis is between  -30 degree to +90 degree. So, what happens in   left ventricular enlargement?  In left ventricular enlargement,   there is a stronger left ventricular vector which  shifts the P QRS axis anticlockwise or leftward.  

And the left axis deviation will be there of more  than -30 degrees in left ventricular enlargement. So, the ECG, the sensitivity of ECG to diagnose  left ventricular hypertrophy is limited. So,   many criteria are being proposed to diagnose left  ventricular hypertrophy in ECG. Most of these  

criteria rely on increased QRS voltage. That is  because, when the left ventricle is hypertrophy,   that means, the thickness of the left ventricular  myocardium is more. So, the amplitude of the QRS   complex will also be more. So, let us see in  the frontal plane, I am concentrating 2 leads,  

V1 and V6; V1 being the right precordial  lead and V6 being the left precordial lead. So, this is the normal uh ECG in a V1, lead  V1. So, here we can see a small R wave and a   deep S wave. This R is contributed to by the  right ventricle, and S is contributed by the  

left ventricle. In left ventricular hypertrophy,  this S will be deepened. The S which co which   is contributed by the left ventricle will be  deepened and you get a small R, deep S in V1.   This, if there is a small r, deep S  like this in V1, it is suggestive of  

left ventricular hypertrophy. What happens in V6? Normally, V6 will have a; because  it is a left precordial lead,   so, the V6 will have a tall R wave contributed  by the left ventricle and a small S wave which is  

contributed by the right ventricle.  So, in left ventricular hypertrophy,   there is an increase in the amplitude of this  R wave contributed by the left ventricle.   So, there are some pointers for a left  ventricular hypertrophy uh in the ECG.  

One I already told you, increased QRS voltage.  The second one is a left atrial abnormality. During diastole, when the mitral valve is open,  the left ventricle and left atrium behaves like a   common chamber. And any pressure or volume  differences in the left ventricle is reflected  

to the left atrium also. So, the presence of an  associated left atrial abnormality is a pointer   for left ventricular hypertrophy. And ventricular  activation time is the time taken for the impulse   to travel through the myocardium to reach the  recording electrode. In case of a left ventricular  

hypertrophy, since the thickness of the myocardium  is more, this ventricular activation time which is   measured from the beginning of the QRS complex  to the peak of the R wave, it is prolonged. Usually, it will be less than 0.05 second.  Here it will be prolonged to more than 0.05  

second. The intrinsicoid deflection is the  point from which this uh impulse reaches the   recording electrode. And so, because the  ventricular activation time is prolonged,   the intrinsicoid de deflection is also  delayed. It is evidently seen in the  

left precordial leads, that is, V5 and  V6. If the amplitude of R in V6 is more   than or equal to the R in V5, that is also  suggestive of left ventricular hypertrophy. Because in left ventricular hypertrophy there is  some abnormality in depolarisation, especially in  

a concentric hypertrophy, it is associated with  abnormalities in repolarisation, abnormalities   in ST-T segments. The 2 most commonly used  repolarisation criteria for diagnosis of   LVH are QRS T angle more than 100 degree and the  T wave which is upright in V2 and more negative  

than 0.1 millivolt in V6. So, in addition to the  findings which we mentioned above, if you see   abnormalities in ST segment and T wave, that is  also suggestive of left ventricular hypertrophy. The reciprocal changes are also present in  the right precordial leads with ST elevation  

and a tall T wave. There are a few criteria  which are used commonly in clinical practice   to diagnose left ventricular hypertrophy in the  ECG. The most commonly used one is Sokolow-Lyon   index. So, it says that uh ah amplitude of  R in V5 or V6 plus the amplitude of S in V1,  

if it is more than or equal to 35 millimetre, it  is suggestive of left ventricular hypertrophy. If the amplitude of R wave in aVL is more than  11 millimetre, that is also suggestive of left   ventricular hypertrophy. Then, another commonly  used criteria is Cornell voltage criteria.  

So, it says that the sum of the amplitude  of R in aVL with S in V3, if it is more than   28 millimetre in men or 20 millimetre in women,  it is suggestive of left ventricular hypertrophy.   Cornell product is the Cornell voltage  multiplied by QRS duration in milliseconds.

And if it is more than or equal to 2440  milliseconds, it is also suggestive of   left ventricular hypertrophy. Then we have  Romhilt and Estes criteria. They assign points   to certain parameters, like 3 points are given  if there is evidence of left atrial abnormality  

or any increase in the voltage of QRS complex  as evidenced by an R or S in limb lead more   than or equal to 20 millimetre; S in V1  or V2 more than or equal to 30 millimetre,   R in V5 or V6 more than or equal to 30 millimetre;  or any ST-T abnormalities without digoxin.

Two points are given if there is a left axis  deviation of more than -30 degrees, and 1 point is   given if there is a slight widening of QRS complex  more than 0.09 seconds. An intrinsicoid deflection   in V5, V6 more than or equal to 0.05 second, and  ST segment or T abnormalities with digoxin. So,  

intrinsicoid deflection, I hope you understood.  It is calculated from the beginning of the QRS   complex to the peak of the R wave, the duration of  that. If it is more than 0.05 second, we say that   there is a prolonged ventricular activation  time or delay in intrinsicoid deflection.

So, if the total score is more than or equal to 5  points, then it is diagnostic of LVH in the ECG.   A score of 4 points is suggestive of probable  LVH. Other ECG changes which are seen in LVH   are a total QRS voltage, that is, the sum  of the amplitude of all the QRS voltage in  

the ECG more than 175 millimetre; presence  of an incomplete left bundle branch block;   attenuation of a small initial  q in the left oriented leads;   abnormal large Q in the inferior leads;  a small equiphasic rs complex in aVF;  

or a U wave amplitude which is increased  in right leads or inverted in left leads. These are also pointers to left ventricular  hypertrophy. So, we have seen like,   all the criterias we have discussed so far uses  the amplitude or the QRS voltage to diagnose  

LVH. But there are some condition in which  there will be left ventricular hypertrophy   without increased voltage in the QRS  complex, like obesity, peripheral oedema,   anasarca, lung diseases like emphysema, patients  with large breasts, biventricular hypertrophy,  

pericardial effusion, pleural effusion, etcetera. So, in all these condition, you will get a ECG  without increased voltage, but the patient will   be having left ventricular hypertrophy. There are  some conditions in which there is increased QRS  

voltage not resulting from LVH, like adolescent  boys, patients with anemia, patients who underwent   left mastectomy, or thin individuals. So, these  conditions have to be kept in mind whenever you   are reading the ECG of any patient. So, this  is ECG number 4. So, what are we seeing here?

Let us concentrate on the V1 to V6 chest leads.  So, let us apply Sokolow-Lyon index here. So,   we will calculate the amplitude of S in V1;  it is coming around 20 millimetre. And we   are calculating the amplitude of R in V6; it is  coming 25. So, the sum of these two is more than  

35 millimetre; so, satisfying the Sokolow-Lyon  index. Let us see the aVL. The amplitude of R   in aVL, it is more than 11 millimetre. So,  that is also suggestive of left ventricular   hypertrophy. If you apply the Cornell voltage  criteria, we can see that R in aVL plus S in V3.

So, R itself here is 15; S is coming around   25; 15+25, it is well more than 28 millimetre. So,  according to Cornell voltage criteria also, this   is suggestive of left ventricular hypertrophy.  If you apply the Romhilt and Estes criteria,  

there is evidence of left at left ventricular  hypertrophy as evidenced by increase QRS voltage;   yes, well beyond 30 millimetre in the leads.  So, yes, that is giving 3 points. And there   are ST-T abnormalities; that is also giving  3 points. So, the score is well beyond 5.

So, according to Romhilt and Estes criteria also,  this ECG is having left ventricular hypertrophy.   Now, let us see right ventricular hypertrophy and  dilatation. So, in right ventricular hypertrophy,   there is a stronger right ventricular  vector which shifts the net QRS axis  

rightward or clockwise, and there is a right  axis deviation of more than or equal to   90 degree. But here you have to  understand that normally itself,   left ventricular muscle mass is much more  than the right ventricle; so, unless the right  

ventricle is severely hypertrophied, this kind  of axis deviation will not be there in the ECG. So, in the frontal plane, in right ventricular  hypertrophy, there will be a tall R wave and   a small S wave, because I already told you, the  initial R is contributed by the right ventricle.  

So, in comparison, I have given the left  ventricular hypertrophy ECG also. So,   in right ventricular hypertrophy,  you get a tall R, small S. Whereas,   in left ventricular hypertrophy, you get  a small R, deep S, in lead V1. In lead V6,  

in right ventricular hypertrophy, you are  getting an R wave which is contributed   by the left ventricle and a deeper S wave  which is contributed by the right ventricle. Whereas, in left ventricular hypertrophy, you are  getting a tall R wave in V6. So, the pointers for  

right ventricular hypertrophy in the ECG are,  right axis deviation of more than or equal to 90   degree; qR complex, a small q, tall R in V1, or an  R wave of amplitude more than 7 millimetre in V1,   or an R S ratio of more than or equal to 1, in  V1. Similar to left ventricular hypertrophy,  

in right ventricular hypertrophy also, because  the right ventricular muscle mass is increased,   there is a delayed onset of intrinsicoid  deflection in V1 more than 0.03 second. We will see a small r deep S complex in the left  oriented leads and an equiphasic RS complex in the  

mid precordial leads. In adults, sometimes  we see an S1, S2, S3 pattern. That is,   a deep S is seen in lead 1, 2, 3, which is also  suggestive of right ventricular hypertrophy.   Presence of the right atrial abnormality  or right bundle branch block may also be  

seen. Similar to left ventricular hypertrophy,  we can see ST segment and T wave changes   in the form ST depression and T inversion  in right precordial leads like V1 and V2. 3 types of right ventricular  hypertrophy are identified. Type A:  

It is the typical RVH pattern with anterior and  rightward displacement of the main QRS vector.   Type B is the one in which we will see an  incomplete bundle branch block. And type C,   there is posterior and rightward displacement  of the main QRS axis. It is seen predominantly  

in patients with chronic lung disease like  emphysema. In that, the lead V1 may look normal,   but we will see a deep S wave in the left  precordial leads with right axis deviation. So, I like to mention about the uh ECG  in chronic pulmonary disease. In chronic  

pulmonary disease like emphysema, there is  over inflation of the lung, which will push   diaphragm downward. So, the heart is now  aligned vertically. P, QRS, T wave axis,   everything is shifted rightward and  inferiorly towards lead aVF. Since lead  

1 is perpendicular to lead aVF, lead 1 will  show very small deflection. This is called as   lead 1 sign in COPD. In addition, there will  be poor R wave progression in the ECG also. So, this is ECG number 5. So, what are we seeing  here? So, in V1, we are seeing a tall R and small  

S. The R is definitely more than 7 millimetre  in amplitude. The R S ratio is definitely more   than 1. And there are, we can see the ST-T changes  also. Can you see the ST-T changes in V1, V2, V3?   So, that is also suggestive of a right  ventricular hypertrophy. This looks like  

a type A right ventricular hypertrophy  pattern. So, let us see this ECG. In this, in V1, we are seeing a QR  pattern; a small Q, tall R, and there is,   in V2 and V3 we can see a right bundle branch  block pattern also. So, this may be type B  

right ventricular hypertrophy. Here, if you  see, here we have a uh ECG suggestive of a right   atrial abnormality also. In combined ventricular  hypertrophy, a combination of these findings are   seen; combination of left ventricular and right  ventricular hypertrophy findings will be seen.  

There is increased voltage of QRS complex,  especially over the transition zones. That is, lead V3 and V4, we will see  a tall R, deep S. Or, there will be   left ventricular hypertrophy with  right axis deviation or right atrial  

abnormality. Or a left atrial enlargement with an  R S ratio in V5, V6 less than or equal to 1, or S   in V5, V6 more than or equal to 7 millimetre, or a  right axis deviation of more than plus 90 degrees.   Or if there is a voltage discordance between  limb and precordial leads. If you see tall R  

in ri left precordial leads, tall R in left  precordial right precordial leads and large   equiphasic QRS in the mid precordial leads,  then this is called as Katz-Wachtel phenomenon. That is also suggestive of combined ventricular  hypertrophy. So, I will show you an ECG. Here,  

we are seeing tall R in right precordial, that is  V1; tall R is seen in left precordial lead, that   is V6; and in the mid precordial lead, we  have kind of a equiphasic RS complex. So,   this is called as Katz-Wachtel phenomenon,  and this is indicative of combined ventricular  

hypertrophy. In heart failure, you will  see a combination of these findings. There may be findings suggestive of left  ventricular enlargement, right ventricular   enlargement, left atrial abnormality, right  atrial abnormality; any combination is possible.  

In addition, we will see arrhythmias, like atrial  fibrillation, premature ventricular complex,   atrial ectopics. So, those kind of  arrhythmias may be present. In addition,   the patient may have complete left bundle  branch block or right bundle branch block  

in the ECG. When these findings are present,  we suspect heart failure. We have to do an   echo to confirm systolic or diastolic dysfunction  of the heart. These are my references. Thank you.