Quick EKG Reference Guide
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• Rate:
   SA: 60-100 	Atrial: 75		
   AV: 40-60 	Ventricular: 30-40

   1 square= 0.04 s; 1 block= 0.20 s
   Rate= 60/[(0.04)(# of squares)]

   Rate:  300 150 100 75 60 50
   Blocks:    1     2      3   4    5    6

   Rate= 6*[# of cardiac cycles] 
		(in a 10 sec strip)

• Rhythm:
   Check for P waves 
	(up in I, II; down in aVR)
   are Ps followed by QRS?
   PR interval 	(normal 0.12-0.20 s)
   QTc = (QT)/(RR)^0.5  
		(normal 0.34-0.42 s)

   Heart Blocks:
	Sinus: missed beats
	1° AV: PR>0.2 s
	2° AV: Type I (Wenckebach)
	   PR progrssively increases
	   culminates in missed beat
	2° AV: Type II (Mobitz)
	   normal P, no QRS response
	3° AV: AV dissociation
	Bundle branch blocks- below

   Premature beats:
	atrial: early, abnormal P
	junctional: normal P or
	   inverted P' (retrograde)
	ventricular: wide QRS >0.12 s
	   no P wave, large T wave
	   may be multifocal

   Tachy-arrhythmias:
 	Paroxysmal atrial tachy.: 
 	   150-250/min. P, narrow QRS
	Atrial flutter: 240-350/min 
	   AV block commonly 2:1 
 	   sawtooth pattern
 	Atrial fib.: 160-200/min
 	   No P waves. irreg.-irreg. QRS
	Supraventricular tachy.: 
	   150-250/min
	   atrial and/or junctional.
	   usually normal QRS
	   may be 2° to: re-entry
	      (nodal or atrial)
	   may see retrograde P'
	Ventricular tach. 100-250/min
	   >=3 PVCs
 	   cardiac arrest, BP=0 
 	Torsades des Pointes: 
	   160-280/min
 	   "twisting of points" 
 	   prolonged QT
	Ventricular fib. 350-450/min
	   irreg. ventricular firing

   Hyperkalemia: 
 	peaked T; flat, wide P. 
	wide QRS, wide QT
	increased PR interval
	sinusoidal at high K+
 
   Hypokalemia: 
 	flat or inverted T waves; 
	U wave, increased PR
	premature beats and tach.

   Hypercalcemia: short QT 
 
   Hypocalcemia: prolonged QT
 
   Digoxin: 
     in therapeutic doses: 
	short QT, flat T,
	curved ST depression
     toxic dose: premature beats,
	heart blocks

   Quinidine: wide P and QRS
 	ST depression 
	prolonged QT, U wave

• Axis:
   Left or Right axis deviation
	LAD:    0 > axis > -90 
	normal: 90 > axis > 0
	RAD:		axis > 90

	      -90 deg

			     [LAD]

180 deg	    -->	      0 deg

			     [normal axis]
 [RAD]
	        90 deg

1.  Left Axis Deviation
     -Normal variant
     -LBBB
     -LAFB
     -LVH
     -WPW
     -Inferior MI
     -Mechanical shifts
     -congenital defect

2.  Right Deviation
     -RBBB
     -LPFB
     -RVH
     -Dextrocardia
     -WPW
     -Infarct of L lateral wall
     -left pneumothorax
     -congenital

   Left or Right rotation 
      (late or early transition in 
       precordial leads respectively)

• Ischemia/Infarction:
   Large T wave, Inverted T wave
	(normal T wave inversion
	 in V1,2 and II, III)

   ST changes:
	Inferior: II,III,AVF
	Lateral: I,AVL
	Anterior: V1,2  (elevation)
	Posterior: V1,2 (depression)

   ST Depression:
	posterior infarct
	subendocardial infarct
	strain
	digitalis
	hypoK+; hypoMq++

   ST Elevation:
	anterior transmural infarct
		(arching ST segment)
	pericarditis (most/all leads)
	Ventricular Aneurysm
	     (persistent elevation 
	       following MI)
	normal variant

   Q waves: (>25% of height, >0.04 s)
	Inferior: II, III, aVF
	Lateral: I, aVL, V6
	Anterior: V1,2,3,4
	Posterior: V6 (also increased
	  R waves and R>S in V1 and V2)
	Not pathologic in aVL, III, V1
	Benign or septal (q - 1-2mm)
	   (in I, II, aVF, aVL, V4,5,6)

   BBB: QRS > 0.12 s

   Left bundle branch block (L BBB):
	RSR' in V5,6; QS in V1
	loss of q in I, aVL, V5, V6
	(superior branch)

   Right bundle branch block (R BBB):
	RR' in V1,2; broad S in V6  	
	(right infero-posterior branch)
 
   L. Anterior hemiblock:
	QISIII; Axis<-30° (LAD)
	2° R in aVR    
	small Q, big R: I, aVL
	small R, big S: II, III, aVF
	(antero-superior fascicle)

   L. Posterior hemiblock:
	SIQIII; Axis>110° (RAD)
	(posterio-inferior fascicle)

• Coronary Vessels:
      vessel: region   [leads ST elevated]
   LAD:
	anteroseptal		[V1-V3]
	anterosuperior	[I, aVL]
	antero-lateral	   [I,aVL,V5,V6]
	posterolateral-
	   apical			[V4-V6]
   Circumflex:
	posterolateral-
	  basal, middle		[R in V1-V3
				and ST depress]
   Diagonal/Circumflex:
	antero-lateral	    [I,AVL,V5-V6]
   RCA:
	posterior			[R in V1-V3
			 	and ST depress]
   Posterior descending (RCA or LCA):
	inferior			[II,III,aVF]

• Pulmonary disease pattern: 
	vertical P, RAD, low voltage, 
	poor R progression

• PE: SIQIIITinvIII
        
• Hypertrophy:
   Left atrial 
	diphasic in V1 
 	    terminal component in V1
	    is >= 1 mm and >= 0.04 s
	wide P >0.12 s

   Right atrial 
	tall diphasic P, 
	P > 2.5mm in II

   Left ventricular 
	SIII+RI >26 mm, RaVL > 15mm
	SV1+RV5 or RV6 >35 mm
	RV5 or RV6 >26 mm
	2° ST-T changes (ST depression
                      and T inversion)
	LV strain: ST segment, T wave
	   in opposite direction to QRS

   Right ventricular
	RV1 > SV1 > 5 mm 
	RV1 + SV5 or SV6 >= 11 mm

   Low Voltage: 5 mm limb; 
		10 mm precordial
______________________________________
by Michael T. Milano, MD PhD
MTMilano@yahoo.com
www.geocities.com/MTMilano/palm/