Serial electrocardiographic changes in idiopathic dilated cardiomyopathy confirmed at necropsy

CARDIOMYOPATHY

Serial Electrocardiographic Dilated Cardiomyopathy

Changes in Idiopathic Confirmed at Necropsy

Robert L. Wilensky, MD, Paul Yudelman, MD, Andrew I. Cohen, MD, Ross D. Fletcher, MD, James Atkinson, MD, PhD, Renu Virmani, MD, and William C. Roberts, MD

Serial electrocardiographic changes in necropsyproven idiopathic dilated cardiomyopathy are evaluated and a method of predicting heart weight using QRS amplitudes is described. In 34 patients with multiple electrocardiograms (mean 3/patient) progressive prolongation of PR interval (0.18 f 0.03 to 0.21 f 0.03, p
From the Department of Medicine and Division of Cardiology, Veterans Administration Medical Center and the Armed Forces Institute of Pathology, Washington, DC, Department of Pathology, Vanderbilt University, Nashville, Tennessee, and the Pathology Branch, National Heart, Lung, and Blood Institute, National Institues of Health, Bethesda, Maryland. Manuscript received March 3, 1988; revised manuscript received and accepted April 4, 1988. Address for reprints: Robert L. Wilensky, MD, Krannert Institute of Cardiology, 1001 West 10th Street, Indianapolis, Indiana 46202.

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lthough electrocardiographic abnormalities are common in patients with idiopathic dilated cardiomyopathy (IDC),*-4 no studies have looked at serial changes. In the present study we describe electrocardiographic findings in 56 patients with necropsyproven IDC; 34 had multiple electrocardiograms. The progressive electrocardiographic changes are evaluated and a method of predicting heart weight in IDC using QRS amplitudes is described.

A

METHODS

The following criteria for diagnosis of IDC had to be met4,5: (1) increased heart weight (>350 g in women and >400 g in men), (2) increased size of both right and left ventricular cavities, (3) absence of significant (>75% cross-sectional area) narrowing of an epicardial coronary artery, (4) absence of significant valvular and pericardial abnormalities, (5) absence of a major congenital cardiac malformation, (6) absence of obstructive pulmonary disease, (7) absence of infiltrative and inflammatory diseases affecting the heart and (8) absence of renal lesions consistent with systemic hypertension. Pathology reports of 197 patients with IDC were reviewed. Electrocardiograms or clinical records could not be retrieved in 89 cases. Of the remaining 108 cases, 23 did not die of their cardiomyopathy, 11 had acute dilated cardiomyopathy and 18 did not have an electrocardiogram in the last 60 days of life or multiple electrocardiograms spanning >50% of their illness or the last year of their life. The 56 patients remaining (138 electrocardiograms) make up the study population. Death resulted from complications of IDC (i.e., low cardiac output failure, arrhythmias or thromboembolism). No patient had another concomitant life-threatening disease or systemic hypertension at least in the last 3 months of life. The Pathology Branch of the National Heart, Lung, and Blood Institute, National Institutes of Health, provided 40 cases; Vanderbilt University Hospital, 7 cases; and the Nashville Veterans Administration Hospital, 9 cases. Each heart was examined by 1 of 3 investigators (WCR, RV or JA). Records were retrieved from the hospitals in which the patients had died. Duration of symptoms of cardiac dysfunction was the time from onset of symptoms of congestive heart failure or significant arrhythmias to death. The body surface area was calculated from height and weight. Serial electrocardiograms-spanning either >50% of the duration of the clinical illness with the last electro-

cardiogram within 180 days of death or the year before death-were available in 34 patients; 50 patients had electrocardiograms within 60 days of death. Electrocardiograms were reviewed by 2 investigators (RLW and AIC) independently and discrepencies in interpretation were resolved by consensus opinion. Results from 18 cases (21 electrocardiograms) have been published previously.4 Conduction abnormalities were defined according to previously defined standards.6 Any Q-wave >40 ms was considered abnormal. Poor R-wave progression was defined as an absence of progressively increasing R-wave amplitudes in leads Vi through V4. Left atria1 abnormality was defined as a wide, biphasic or downward directed P wave in leads Vi and V2 with an increased Pwave duration to PR-interval ratioe7 Right atria1 abnormality was the presence of peaked P waves in leads II, III and aVF with a voltage >2.5 mV.7 Left ventricular hypertrophy was determined by Estes and Romhilt criteria and by a method using QRS voltage criteria.8 Patients with bundle branch block were included in both determinations. The amplitude of QRS waves, defined as the number of millimeters between the point of maximum inflection (top of the R wave) and deflection (bottom of the Q or S wave, whichever was greater), was measured for each lead (Figure 1). Total Vi through V6 and total 1Zlead QRS amplitudes were obtained by adding the amplitudes of the individual leads. Amplitudes were standardized to 10 mm equaling 1 mV. Statistical analysis in the correlation of heart weight and cardiac mass index with electrocardiographic determinations of left ventricular hypertrophy used linear regression. The paired t test was used in determining change in PR intervals, QRS duration, QTc interval, QRS and T-wave axis between the initial and final electrocardiogram. In addition, paired t test evaluated change in voltages and Estes-Romhilt score between the initial and final electrocardiogram. RESULTS

The 56 patients ranged in age from 17 to 73 years (mean 49); 33 were white (27 men and 6 women) and 23 were black (19 men and 4 women). Duration of symptoms of cardiac dysfunction ranged from 180 to 7,660 days (mean 1,755). In 3 cases the exact disease duration could not be discerned but was >I year. Heart weight ranged from 400 to 1,050 g (mean 675) in men and from 400 to 860 g (mean 650) in women. Heart weight did not correlate with disease duration. Ventricular wall thickness was obtained in 31 cases. The left ventricular free wall thickness was 0.9 to 2.5 cm (mean 1.6). The right ventricular free wall thickness was 0.2 to 1.0 cm (mean 0.8). In 13 patients grossly visible left ventricular scars were present. In the 34 patients (28 men and 6 women) with multiple electrocardiograms (Table I) the last electrocardiogram was recorded within 60 days of death in 28 patients and within 180 days in the remaining 6 (average 32). Duration of symptoms of cardiac dysfunction aver-

aged 1,601 days (1,507 days in men and 2,391 days in women) and ranged from 365 to 4,015 days in men and from 1,065 to 7,665 days in women. Available electrocardiograms spanned 865 days in men (57% of disease duration) and 1,924 days in women (80%). For men and women combined electrocardiograms spanned an average of 1,057 days, representing the latter 65% of the disease. Digoxin was prescribed in 27 patients, procainamide in 5 (1 patient had both procainamide and mexiletine), quinidine in 3 and phenytoin in 1. Heart weight averaged 681 g in men (range 400 to 940) and 623 g in women (range 400 to 800). Of 34 patients, 24 (71%) remained in sinus rhythm throughout their illness; 4 patients had atria1 fibrillation on all electrocardiograms, 4 other patients developed atria1 fibrillation and 2 additional patients developed other atria1 tachyarrhythmias. Heart rate averaged 94 beats/min on the initial electrocardiogram and remained constant. Of the 24 patients in sinus rhythm, the PR interval lengthened in 16 patients (67%), decreased in 4 (17%) and did not change in 4 (17%). Mean PR interval (Table II) increased from 0.18 second on the initial electrocardiogram to 0.21 second on the final electrocardiogram (p
T

TOtd Wivolts

R JL

;:”

R

P

P

RR : 4-v -I P

T

1

T

+

1

0

S

T

P

R

R

P

P

L

T

Q

I

4

Q L

S

FIGURE l.The method of QRS amplitude mm). From Siegel and Robert@ reproduced from C.V. Mosby.

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measurement (in with permission

AUGUST 1,1988

277

IA

2,190

699

1.035

2.980

2,355

2.190

1,825

2,190

1,825

1.460

600

47. w

48, B

48, B

48,W

49, w

50, B

50, B

50, w

51, B

56. B

56, B

?

QW

4,015

?

39, w

ww

1,095

35, w

600

540

28, W

448

365

84

1,095 530 350 28 1,023 684 399 180 2,130 1,400 1,030 330 95 1,625 913 180 430 1 395 9 380 74 19 1,660 4Do 1 556 56 1 500 230 1

ii 80 73 65 70 95 67 90 74 105

98 96 102 75 102 98 112 89 74 60 62 66 70 105 90 90 ml 105 124 100 59

115 95 96 102 74 85 120 110

2,m

580 265 55 591 44-o 120 917 54

loo 115 82 88 loo 125 77 110 80 76 88

HR Own)

Changes

190 9 280 88 1 990 5 425 60 400 3

Interval (days) ECGto Death

Electrocardtographic

Durabon (days) Symptoms ofCD

Serial

22, w

4ge at Death :yrs), Race

rABLE

S S s S s S s S s S S s s s s s s AT AF AF s S s S s S s S S s s s

s S S AF AF AF s s

s

s s S s s S s AF AF S s

Rhythm

0.24 0.28 0.29 0.18 0.22 021 0.14 0 19 0.28 0.16 0.17 0.21

0.16 0.24 0.24 0.28 0 16 0.17 0.19 0.20 0.21 0.20 0.21 0.20 0.21 0.16 0.17 0.20 0.18 -

0.21 0.21 0.16 0.19 0.19 0.20 0.19 0.22 0.25 0.16 0 16 0.16 0.16 0.21 0.20

PR

Interval(s)

0.41 0.48 042 0.45 0.45 0.47 0.48 0.48 0.48 0.45 0.45 0.50 0.48 042 0.41 0.44 0.44 0.44 0.45 0.50 0.41 0.46 0.43 0.43 044 0.41 0.44 0.49 0.48 0.42 0.43 0.47 0.49 043 0.44 0.44 0.49 0.47 0.46 0.45 0.44 0.55 0.42 0.45 0.40 0.45 0.48 0.44 0.45 046 0.52 0.46

0.08 0.10 0.12 0.12 0.06 0.08 0.10 0.11 0.09 0.10 0.12 0.16 0.14 0.11 0.11 0.12 0.10 0 10 0.12 0.12 0.10 0.12 0.13 0.11 0.12 0.14 0.12 0.16 0.16 0.11 0 10 0.12

QTc

0.08 0.08 0.08 0.12 0.12 0.09 0.08 0.10 0.16 0.12 0.14 0.05 0.08 0.08 0.09 0.10 0.11 0.12 0.14 0.16

QRS

in 28 Men with Autopsy-Proven

0 -30 -40 -45 -10 -5 0 5 45 10 -15 -45 -90 -30 -15 -15 -60 -60 100 90 -5 -5 5 -120 -120 -120 -90 -120 -130 0 -10 90

15 -45 -30 -75 60 -30 -45 -30 -15 -45 10 -30 -45 -70 45 -15 -15 -130 -120

I

QRS

Axis(o)

idiopathic

-120 -130 -90 90 I I I I 90 90 90 90 90 90 90 90 I I 1 I 170 170 175 I 90 I I I I 65 -30 35

0 0 LAFB LAFB LAFB 0 0 IVCD, LAFB IVCD,LAFB 0 IVCD, tAFB 0 LAFB LAFB LAFB 0 Left BBB Left BBB Right B8B Right BBB, LAFB 0 LAFB IVCD. LAFB Left BBB 0 0 Inc Left BBB Inc Left BBB 0 Left BBB Left BBB Left BBB Left BBB Right IVCD Right IVCD Right IVCD LAFB tAF8 0 IVCD 0 0 IVCD LAFB LAFB IVCD, LAFB Rgght BBB Rrght BBB Rrght BBB IVCD IVCD IVCD

Conductron Abnormal@

Cardiomyopathy

I I -120 I 75 I I 135 120 90 90 80 I 130 50 90 I I 90 I

T

Dilated

241 206 225 313 144 174 151 140 160 196 159 111 117 190 163 166 78 86 114 92 191 192 219 61 93 70 75 45 43 218 218 151

73 99 191 190 147 92 138 84 75 164 194 124 140 146 125 135 116 113 116 145

Total

192 152 158 242 110 145 135 125 120 158 124 70 80 158 148 148 61 65 loo 76 141 150 165 51 76 56 55 37 35 178 175 137

56 77 143 145 110 82 115 58 52 136 154 80 96 107 100 108 95 95 86 115

V14

QRS Voltage (mm)

49 54 67 71 34 29 16 15 40 39 35 41 37 32 15 18 17 21 14 16 50 42 54 10 17 14 20 8 8 40 43 14

17 22 48 45 37 10 23 26 23 28 40 44 44 39 25 27 21 18 30 30

I, II, Ill R, L. F

4 7 10 11 6 5 6 6 0 5 3 4 5 4 6 7 4 1 0 0 1 1 4 4 2 4 3 6 6 8 8 4

3 3 3 3 6 0 5 5 5 6 7 1 6 6 6 2 2 2 3 3

EstesRomhilt Score

0’ 0 0 t t t

: 0 + +

0’ 0

;: 0 0 t

0 0 0 0 0 0 t 0 + t t +

i -It

0’ 0 0 0 + 0 t

0’ t

0 0 + 0 0

VPC

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 +

0 0 0 0 0 0 0 --4000 0 0 0 0 0 O 0

Rght

Atnal Abnormality

0’ + + t + +

i 0 0 0 0 t t t + + 0 0 0 0 0 0 t

+ t t t t t +

0 0

0’ t t t -

0

0 0 0 0 0 0 t

Left

0

0

670

0

+

+

0

+

475

650

790

710

650

705

t

0

660

650

0

0

t

+

0

t

0

0

900

620

750

700

500

940

540

700

LV Scar

IA

(continued)

1,065

1,065

1,095

7

7,665

1,065

Age at Death (yrs), Race

33, B

53, w

55, w

56, W

63, W

67, B

90 136

105 96 72 94 92

1

5

118

86

980

85

7,600 3,650 700 2

900

90 68 120 105 120 112 127 90 80

HR @Pm)

910 590 4 520 399 30 6 635 180

Interval (days) ECGto Death

0.48 0.50 0.43 0.47 0.45 043

043 I 0.44 044 0.45 0.41 0.43 049 0.55 0.49 0.44 045 0.49 049 0.40 0.74 0.48 050 055

QTc

S AF

s S S s s

s S

s s s S s S

AF AF AF

Rhythm

-

0 16

0 18 0 18 0.20 0.20 0 18 0.20 0.24 0.20 020 0.16 0.19 0.12 020

-

PR

Interval(s)

0.12

0.12

0.06 008 0.10 0 13 0.11 0.12 0.16 012 0.12 0.13 0.20 0 16 020

0.14

0.11

0.09

QRS 0.44 0.49 0.53 0.45 0.51 0.54 043 0.44 049 058 048 0.43 050 045 052 0.54 0.47 0.47

QTc

90 I I 90 90 90

I I 90 I I I

195

I I I -30 I -30 -30 I I 115 130

110

T Left BBB Left BBB Left BBB Left BBB Left BBB 0 Left BBB 0 IVCD IVCD 0 0 IVCD, LAFB IVCD, LAFB 0 0 IVCD IVCD, LAFB Rrght BBB, LAFB Left BBB Left BBB 0 0 0 0

Conduction Abnormalrty

-30 -60 -60 -60 -130 -120 -45 30 -30 -30 -15 -30 -40 30 30

I

75 120

QRS

AXIS(O)

I

90 90 90 90 90 90 30

90 90 90 90

90

90 -90

T

0

0

IVCD, LAFB IVCD Left BBB Left BBB Left BBB Left BBB Left BBB

0 0

IVCD IVCD LAFB LAFB IVCD, LAFB Left BBB

0

Conduction Abnormality

Idiopathic Dilated Cardiomyopathy

-15 -30 -15 30 80 90

-45 -90 -90 -90 -85 30 -60 30 70 90 -15 -15 -75 -60 80 90 -30 -30 -45

QRS

AXIS(o)

31 91 36 23

17 13 46

110 94 116 78

163 131 103 90 69

101 78 111

188 171 130 104 82

118 91

95 95

203 177 136

264 225 195

89

163

210

120

114 66

59 142

63 81

68 60 67 76

58 76 26

Vi4

144 98

84 164

80 93

117 108 114 143

63 98 47

Total

31

39 48 59

47

30 32

25 22

17 12

49 48 47 65

5 22 21

I, II, Ill R, L, F

(mm)

38 30

39

28 41

120

68

124 112

94 75 42

181 176 134

100

21

40 27 14 13

91

QRS Amplitude

133 125

159

168 152 153

157 112 275 251 176

28 17 49

102 123 148

130 141 197 141 185 152 101

25

I, II, Ill R, L, F

Vl-6

Total

QRS Voltage (mm)

AF = amal f~bnllat~on.AT = at& tachyarrhythm~a, B = black. BBB = bundle branch block, bpm = beats/mln, CD = cardiac dysfunctw. HR = heart r&e. HW = heart weight, I = ndetwnnate. an~or iasclcular oiock. LV = left ventricular, S = sws, VPC = ventricular premature complex: W = white, + = present. 0 = absent, - = unknown.

Duration (days) Symptoms ofCD

008 009

0 10

0.19 0.30 -

0.16 0.16 0.08

0.19

012

0.10 0 10

0 12 009 0.12 0.12 006 008 012 0.12 0.09

0.10

0 13 0.12 0.12 0.14 0 15

QRS

0.18 0.20 0.16

020 -

0 18

024 0.22 0.17 0 16 0.18 0.16 0.22 020 0.20 021 0.17 0.16

PR

Interval(s)

ldiopathkz Dilated Cardiomyopathy

Changes in SIX Women with Autopsy-Proven

125

2,190

19

s AT

97 65

3 360

S

100

s s s S s AF

s s S s s s s S AF AF S s AF AF s s

Rhythm

98 130 98 92 115 84 102 125 115 90 82 75 82 100 105 90

HR (bw)

82 94 68 76 75

470 40

990 600 57 1 335 1 720 335 1

1

430 120

1

440 5 1,200 835 77 1,500

Serial Electrocardiographic

540

IB

2,300

65, W

70, w

TABLE

1,460

63, W

1,970

61, B

1,900

540

58, B

61, B

2,500

58, W

730

1,460

57, B

61,W

450

h's) ECG to Death

(days) Symptoms ofCD

57, B

Age at Death (yrs), Race

Interval

Changes in 28 Men with Autopsy-Proven

Duration

Serial Electrocardiographrc

TABLE

t 0 0

4 5

0’ 0 0 0 t t

t

0 0 0 0 0 0 0 0

0

0 0 0

0

0 0

-

Rrght

Atnal Abnormalrty

0

0 0

0 0 0

ix = 8ncomplete, I’JCD = lntravenhlcuiar

6 6 8 8 6 6 3 1

0

0

8

:

0’ 0 0

t

1 3 3 2 3

VPC

0

0

EstesRomhrlt Score

t 0

1 1

0' 0

6 6 4

-

0 0 0 0

0' t 0 0

t

0 0 0 0 0 0 -

0

t i t t 0 t 0

0 0 0 0 0

Rrght

Atrral Abnormalrty

0 0 0 0 0

VPC

a

6 7 5 2 3 3 2 1 4 4 7 7

1

8 8 7 7 8

EstesRomhilt Score

t t t t t t 0 0

0

t t t

t

t t

-

620

800

550

615

750

400

E

840

645

770

780

655

570

720

0

t

0

0

0

0

LV Scar

0

0

0

t

0

t

0

0

0

760

610

0

710

LV Scar

conducbon dew. IAFB = left

Left

0

t 0

0 t +

-

0' 0

t

0 t 0 0 t t -

0’

t t 0 t

Left

THE ECG IN IBC

TABLE II Electrocardiographic Cardiomyopathy

PR

Changes

in Chronic

TABLE Ill Abnormalities on the Last 12-Lead Electrocardiogram Recorded Within 60 Days of Death Adults with Idiopathic Dilated Cardiomyopathy

Dilated

No.

Initial Determrnation

Determination at Death

p Value

24

0.18

f 0.03

0.21

f 0.03

0.0007

34

0.10

f 0.02

0.13

f 0.03

<0.0001

33

0.45

f 0.03

0.49

f 0.06

NS

33

-15

f 60

-27f64

NS

Age (yrs): range (mean) Men/women Whrte/black Duration of symptoms of cardiac dysfunction (mos): range (mean) Interval KG to death (days): Range (mean) Heart weight(g): range (mean) Left ventricular scar (%) Heart rate (beats/min): range (mean) Rhythm Atrial fibrillation (%) Atnal flutter (%) Atrial tachyarrhythmia (“7) PR interval (s): range (mean) QRS interval (s): range (mean) QTc interval (s): range (mean) QRS axis (degrees): range (mean) T-wave axis (degrees): range (mean) Conduction abnormalities Left BBB only (%) Right BBB only (%) RBBB + left anterior fascicular block (%) IAFB only (%) IVCD only (%) lAFB + IVCD (%) Ventricular premature complexes (%) Atrial abnormality Right alone (%) Left alone (%) Both (%) Abnormal Q waves (%) Poor R-wave progression (%) QRS voltage (mm) Total: range (mean) I+II+III+R+L+F:range(mean) Vs to Vs: range (mean) Estes-Romhilt score: range (mean)

interval (s)

QRS interval

(s)

QTc interval QRS axis Ww=s) Total QRS amplitude Vl to vlj amplitude

(s)

34

142 f 53

133 f 54

NS

34

108 f 41

104f43

NS

(mm) (mm)

NS = not slgndcant.

Of the 34 patients, 28 (82%) developed conduction abnormalities (Table I). Bundle branch block was seen in 13 patients (38%) with 10 having left and 3 having right bundle branch block. Six patients developed left bundle branch block within the period studied and 1 developed a right bundle branch block in his final year. Two of 3 patients with right bundle branch block also had left anterior fascicular block. Anterior Q waves were present on the last electrocardiogram in 19 of 56 patients. Poor R-wave progression was seen in 49 patients. Of the 13 patients with left ventricular scars, 4 had anterior Q waves (31%); of the 43 patients without left ventricular scars, 15 (35%) had Q waves. All 13 patients with left ventricular scars had

tI-

BBB = bundle branch block: IVCD = intraventmular antenor fasacular block.

in 50

17-73 (50) 41/9 30/20 8-256 (57) l-60 (18) 400-l ,050 (684) 9 (18) 58-l 50 (96) 7 (14) 2 (4) 2 (4) 0.14-0.29 (0.20) 0.0&-0.20 (0.12) 0.36-0.74 (0.48) -130 to +130 (-21) -90 to +195 (76) 41 18 (36) 2 (4)

w 7 (14)

8 (16) 5 (10)

22 N-4 l/39 (3) 20/39 (51) s/39 (8) 18 (36) 43 (86) 43-313 (138) 8-71(32) 26-242 (106) O-l 1 (4.7) conductm

delay: LAFB = left

poor R-wave progression (100%) and 36 of 43 (84%) patients without scars had poor R-wave progression. In the period examined, the latter 65% of the patient’s clinical disease, the Vt to V6 and total QRS amplitude remained constant (Table II, Figure 2). The Estes-Romhilt score increased insignificantly from 3.7 to 4.5. Table III lists results of 50 electrocardiograms obtained within 60 days of death. Vt to Vs (r = 0.55, p
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This is the first study analyzing more than one 12lead electrocardiogram in patients with autopsy-proven IDC. Our results show a progressive increase in PR in-

terval and QRS duration (Figure 5). Many electrocardiograms had ventricular premature complexes, anterior Q waves and poor R-wave progression (Table I and III). Anterior Q waves and poor R-wave progression appear unrelated to left ventricular scarring. Progressive conduction disturbances were common. Both 12-lead and Vr to Vg QRS amplitude correlated better with heart weight than did the Estes-Romhilt criteria for left ventricular hypertrophy. Significant increases in PR interval and QRS duration were seen during the disease process. While prolonged PR interval and QRS duration have been noted previously,1>4 our study is the first to show the progressive nature of the increase. While the administration of digitalis invariably increased PR interval the progressive nature of the increase argues for an underlying organic cause of PR prolongation. The increase in QRS duration was not due to medications as only 9 of 34 patients were prescribed medications that

prolong QRS intervals. Fibrotic infiltration of the conduction pathways could prolong the PR interval and librous tissue infiltration of the ventricular myocardium9J0 could prolong the QRS complex. Myocardial cell hypertrophy also may play a role in increasing the con-

600 550

-

t: s

500 -

ii

450 -

2

400 -

2 E

350 300 -

1100 1000

250 0

200 1::

p < 0.0001

J.

0-Q-

400300 / O&k&

0

0

0 0

0

50

a v ' n i ' I n n ' 75 100 125 150 175 200 225 250 275300

p 4 0.0001

A

c3 E

r = 0.51

0

TOTAL

r = 0.68

0

50

A

100 150 200 250 300 TOTAL

' 325

350

QRS VOLTAGE

600 1

QRS VOLTAGE

8001

500 o 400 1

oka

B

0

0

0

o

50

300 250

r = 0.55 pco.ooo1

m ’

75 100 Vl

’

r = 0.75 0

oq-

c 175’ 200’ 225’ 250n ’

pc 0.0001

50 100 150 200 250

B

QRS VOLTAGE

FtGURE 3. The relation between QRS amplitude criteria and heart weight at necropsy in 50 patients with chronic idiopathic dilated cardiomyopathy with electrocardiograms reeocded within SO days of death. A, correlation of total 12-lead QRS ampllls and heart weight; 8, correlation of Vi threugh Vs QRS amplitude and heart weight.

O

200

125 150 -V6

00 0

Vl - V6 QRS VOLTAGE

FIGURE 4. The correlation between QRS amplii criterk, on the last recorded electrocardiogram befure death, and cardiac mass index at necrapsy in 31 patients. A, total 12-lead QRS amplitude and cardiac mass index; 6, Vi through Vs QRS amplitude and cardiac mass index. THE AMERICAN

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THE ECG

IN DC

duction time. Progressive prolongation of the PR interval and QRS duration may indicate continued fibrous tissue infiltration. Conduction abnormalities were common (82%). Left bundle branch block, left anterior fascicular block and intraventricular conduction delay occurred often while few hearts had right intraventricular conduction disturbances. This finding is similar to results published earlier.3p4 Of our patients with conduction abnormalities, 68% had progressive disturbances in the time period studied. This observation supports evidence that conduction abnormalities in IDC are more common in patients with clinical courses > 1 year.ll The conduction abnormalities may be an electrocardiographic marker of increasing interstitial myocardial fibrosi@I4 or due to increasing left ventricular hypertrophy. Frontal plane and total 12-lead QRS amplitudes correlated with heart weight better than the Estes-Romhilt score did and they were unchanged during the period of study. Correlating Vi to V,j or total 1Zlead QRS amplitudes with the cardiac mass index yields a more accurate indication of heart weight at necropsy. Recent studies have shown that Estes-Romhilt criteria are inadequate in evaluating left ventricular hypertrophy in chronic aortic regurgitationi and in amyloidosis.16 A new method of using total 1%~lead QRS amplitude has been applied7 and correlated with heart weight in aortic regurgitation,15 amyloidosis16 and IDC.4 Odom et all7 established standards in normal hearts. Total QRS amplitude averaged 127 mm, ranging from 80 to 185 mm with values remaining constant the last 5 years of life. Roberts and Day15 suggested that 175 mm might be considered the upper limit of normal with values >175 mm representing left ventricular hypertrophy (93% specificity). Roberts et al4 have shown that total electrocardiogram amplitude in IDC ranges from 75 to 250 I

II

34 MoHlli5 FwOR’TO DENtI

FIGURE function

282

5. Serial ebcurred

Ill

AVR

electrocardiograms 34 months before

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idiopathic

62

mm (mean 153), similar to the results of the present study. No studies have looked at Vi through Vg amplitude as a marker of left ventricular hypertrophy but in 1 studyi the mean was 90 mm (range 54 to 134). In the present study total QRS amplitude in IDC was 138 mm and the Vi to Vg voltage was 106; these values are only slightly higher than the amplitude in normal patients. No studies have correlated 1Zlead QRS amplitude criteria with cardiac mass index. It would be difficult to diagnose IDC purely on amplitude criteria, but the criteria can be an indicator of heart weight. Although virtually all patients with IDC have biatria1 enlargement only 11% had right atria1 abnormality and 59% left atria1 abnormality on electrocardiogram. Previous studies have shown that P-wave amplitude does not correlate with either left or right atria1 weights at autopsy’* and only 53% with left atria1 abnormality on electrocardiogram had echocardiographic evidence of increased left atria1 dimension.19 Our results support the conclusion that the electrocardiogram is insensitive in diagnosing atria1 abnormalities. A limitation of this study is its retrospective nature. We were, therefore, unable to determine exactly when electrocardiographic changes occurred. In addition, criteria for entering this study included the presence of electrocardiograms recording >50% of the disease duration with the last electrocardiogram within 6 months of death or electrocardiograms spanning the last year of life. Thus, a number of patients dying suddenly may not have had an electrocardiogram in the time period necessary for inclusion. Because some investigators believe that left conduction delay and ventricular arrhythmias represent significant risk factors for early death,20 our results may underestimate the degree of conduction abnormalities or ventricular arrhythmias present in patients with IDC.

v1

dilated

v2

cardiomyopathy.

V3

V4

Onset

%

of symptoms

‘6

of cardiac

dys-

Our study did not correlate the degree of interstitial myocardial fibrosis with the PR interval, QRS duration or conduction abnormalities. It has been well documented, however, that interstitial fibrosis is a common tinding in IDC4>9Jo and the presence of interstitial myocardial fibrosis has been correlated previously with conduction abnormalities.‘*-l4 Acknowledgment: The authors gratefully acknowledge William Green, MD, for his assistance in obtaining patient records and Elisabeth Alcenius-W for her excellent graphic skills.

REFERENCES

1. Hamby RI, Raia F. Electrocardiographic aspects of primary myocardial disease in 60 patients. Am Heart J 1968;76:316-328. 2. Stapleton JF, &gal JP, Harvey WP. The electrocardiogram of myourdiopathy. Prog Cardiovasc Dis 1970;13:217-239. 3. Segal JP, Stapleton JF, McClellan JR, Wailer BF, Harvey WP. Idiopathic cardiomyopathy. Clinical features, prognosis and therapy. Curr Probl Cardiol 1978;3:1&49. 4. Roberts WC, Siegel RJ, McManus BM. Idiopathic dilated cardiomyopathy: analysis of 152 necropsy patients. Am J Cardiol 1987~60:1340-1355. 5. Roberts WC, Ferrans VJ. Pathologic anatomy of the cardiomyopathies. Idiopathic dilated and hypertrophic types, infiltrative types, and endomyocardial disease with and without eosinophilia. Hum Pathol 197X6:287-342.

6. Willems JL, Roblcs de Medina EO, Bernard R, Coumel P, Fisch C, Krikler D, Mazur NA, Meijer FL, Morgensen L, Moret P, Piss Z, Rautaharju PM, Surawicz B, Watanabe Y, Wellens HJJ. Crrteriafor intraventricular conduction disturbances and pre-excitation. JACC 1985;5:1261-1275. 7. Surawicz B. Electrocardiographic diagnosis of chamber enlargement. JACC 1986;8:711-724. 6. Siegel RJ, Roberts WC. Electrocardiographic obsernationr in severe aortic

valve stenosis: correlative necropsy study to clinical, hemodynamic, and ECG variables demonstrating relation of 12-lead QRS amplitude to peak systolic transaortic pressure gradient. Am Heart J 1982:103:298-301. 9. Dick MR, Unverferth DV, Baba N. The pattern of myocardial degeneration in nonischemic congestive cardiomyopathy. Hum Pathol 1982;13:740-744. 10. Factor SM, Sonnenblick EH. Thepathogenesis of clinical and experimental congestive cardiomyopathies: recent concepts. Prog Cardiouasc Dis 1985;27:395420. 11. Benjamin IJ, Schuster EH, Buckley BH. Cardiac hypertrophy in idiopathic dilated congestive cardiomyopathy: a cliniropathic study. Circulation 1981; 64:442-447. i2. Unger PN, Greenblatt M, Lev M. The anatomic basis of the electrocardiographic abnormality in incomplete left bundle branch block. Am Heart J 1968;76:486-497. 13. Lev M, Unger PN, Rosen KM, Bharati S. The anatomic substrate of complete left bundle branch block. Circulation 1974;50:479-486. 14. Kulbcrtus HE, Demoulin JC. Pathological basis of concept of left hemibibck. IK Wellem HJJ, Lie LI, Janse MJ, eds. The Conduction System of the Heart. Structure, Function and Clinical Implications. Philadelphia: Lea and Febiger, 1976:287-296. 15. Roberts WC, Day PJ. Electrocardiographic observations in clinically isolated, pure, chronic, severe aortic regurgitation’ analysis of 30 necropsy patients aged 19 to 65 years. Am J Cardiol1985;55:431-438. 16. Roberts WC, Wailer BF. Cardiac amyloidosis causing cardiac dysfunction analysis of 54 necropsy patients. Am J Cardiol 1983:52:137-146.

17. Odom H II, Davis JL, Din H, Baker BJ, Roberts WC, Murphy

ML. QRS

voltage measurements in autopsied men free of cardiopulmonary disease: a basis for evaluating total QRS voltage as an index of left ventricular hypertrophy. Am J Cardiol 1986;58:801-804. 16. Mazzoleni A, Wolff R, Wolff L, Reiner L. Correlation between component cardiac weights and electrocardiographic patterns in I85 cases. Circulation 1964;30:808-829. 19. Josephson ME, Kastor JA, Morganroth J. Electrocardiographic left atria1 enlargement. Electrophysiologic, echocardiographic and hemodynamic correlates. Am J Cardiol 1977:39:967-971.

20. Unverferth DV, Magorien RD. Moeschberger Leier CV. Factors influencing the one-year mortality Am J Cardiol

THE AMERICAN

ML, Baker PB, Fetters JK, of dilated

cardiomyopathy.

1984;54:147-152.

JOURNAL

OF CARDIOLOGY

AUGUST

1,1988

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