journal of lnternal Medicine 199 1 : 229 : 2 5 3-2 5 6
ADONIS
09 5468209 100044 7
Atrial fibrillation and left atrial enlargement : cause or effect? J. S. ANDERSEN, H. EGEBLAD, U. ABILDGAARD, J. ALDERSHVILE & J. GODTFREDSEN From the Division of Cardiology. Medical Department F . Herlev Hospital. University Hospital of Copenhagen. Denmark
Abstract. Andersen IS, Egeblad H.Abildgaard U, Aldershvile J, Godtfredsen J (Division of Cardiology, Medical Department F. Herlev Hospital, University Hospital of Copenhagen. Denmark). Atrial fibrillation and left atrial enlargement: cause or effect Z Journal oJlnterna1 Medicine 1991; 229: 253-256. In a blinded controlled study, 58 consecutive patients with definite left atrial enlargement (M-mode dimension of at least 45 mm) were followed up after 1-2 years. The aim of the study was to examine the following: (a) the prospective risk of developing atrial fibrillation (AF); and (b) the effect of the heart rhythm on the left atrial size. Of 36 patients in sinus rhythm, one developed paroxysmal AF and one developed persistent AF during a median follow-up period of 20 months. Thus the incidence of new AF was 5 % per year. Eighteen patients died before scheduled echocardiographic follow-up. but in the remaining subjects the left atrial dimension did not change significantly : the median increment was 1 mm in 20 patients who sustained sinus rhythm vs. 2 mm in 16 patients with chronic AF (P > 0.05). Although left atrial dilation may cause AF and vice versa, this study demonstrated that the incidence of new AF is low, despite the fact that the left atrial dimension is substantially increased. Similarly, AF per se does not appear to have any major impact on the left atrial dimension. K e y w o r d s : atrial dilation, atrial fibrillation, echocardiography.
Introduction The association between atrial fibrillation (AF) and dilation of the left atrium (LA) is well recognized, although the causal relationship between AF and LA dilation remains controversial [l-51. In this study, the risk of developing AF was examined prospectively in patients with LA dilation and sinus rhythm. In addition, an analysis of the effect of the heart rhythm on LA size was performed.
Patients and methods The study was based on 739 consecutive echocardiographic examinations performed on patients who had been admitted to a district hospital over a period of 18 months. The examinations were carried out by four senior cardiologists who were experienced in echocardiography. All examinations were performed
for diagnostic work-up in accordance with generally accepted indications [ 6 ] .Eighty-two of the patients had definite LA dilation, here defined as an LA dimension of > 45 mm recorded by 2D-guided M-mode echocardiography [ 71. These patients were eligible for inclusion in the study, but 1 5 subjects who died during admission were excluded due to lack of follow-up data. The cause of death was heart failure in the majority of cases, although some patients succumbed because of pneumonia, azotaemia, malignant diseases and malignant arrhythmias. An additional nine patients were excluded, of whom two refused to participate in the follow-up, and seven underwent interventions or other significant change in the basic condition, with a consequent reduction of left atrial strain (e.g. valve replacement, birth after pre-eclampsia, haemodialysis). The remaining 58 patients were included in the study for follow-up after 1-2 years. At the follow-up, physical 253
254
J. S. ANDERSEN et al.
Table 1 . Characteristics of the 40 patients who completed follow-up: data were recorded at entry to the study Sinus rhythm ( n = 2 0 ) ( 1 5 M 5F)
Atrial fibrillation (n=20)(11M9F)
P-value
Left atrial dimension (mm) Left atrial index (mm/m') Functional class (NYHA) Follow-up period (months)
5 5 (22-80) 4 8 (46-54) 25 (20-32) I1 (1-111) 2 0 ( 10-24)
59 (43-77) 50 (46-67) 2 6 (21-38) 111 (I-IV) 21 ( 1 1-27)
NS NS NS NS NS
Cardiac condition Primary valve disease Acute myocardial infarction Cardiomyopathy Hypertensive heart disease Chronic ischaemic heart disease Congenital heart disease
7 5 4 2 2 0
Age ( y e a 4
Median values and range are listed ( P > 0.05 for all comparisons).
Table 2. Medical treatment of patients in sinus rhythm at entry to the study n No medication Digoxin and diuretics Digoxin. calcium-blockers and diuretics Digoxin. calcium-blockers, diuretics and beta-blockers Digoxin Calcium-blockers and diuretics Beta-blockers and diuretics Diuretics
8 10 10 1
Total
35.
1
2 1
2
'The 35 patients include 2 0 subjects who completed follow-up and 1 5 patients who died during follow-up, and for whom an BCG was recorded after the initial examination.
examination, ECG and echocardiography were performed. Echocardiography was performed without knowledge of the patient's history or the results of the previous echocardiographic examination. If the patients's history included spells of palpitations, or otherwise suggested paroxysmal atrial fibrillation, information was obtained from general practitioners, other hospitals and 24-h Holter monitoring. Thyroid status was determined in patients with AF, and all were found to have normal thyroid function. During the follow-up period, the patients were treated medically in accordance with their basic heart disease (Tables 1 and 2).
Statistics
.
Rank-sum tests for paired or unpaired samples were used when appropriate.
Results Eighteen of the 58 patients died before the follow-up examination. Two of the 1 8 patients had chronic AF, and sixteen were in sinus rhythm at the original admission. Echocardiographic follow-up data were not available for this group. However, 1 5 of the 16 patients who were originally in sinus rhythm had one or more ECG recordings performed after the first admission. The median observation period (with range) from the original admission to the date of the most recent ECG was 5 (1-19) months. and the cumulative observation time was 99 months in these patients. One of the patients developed persistent AP. The causes of death in the 18 patients were acute myocardial infarction, heart or multiorgan failure, and cancer. However, the definite cause of death was unknown in seven patients who died outside hospital; autopsy was not performed in these cases. Forty patients completed the follow-up, which was performed after 2 1 (10-2 7) months. At the original admission, 20 patients were in sinus rhythm, none of whom had a history of previous AF. Of the remaining 20 patients, 1 6 had chronic and four had paroxysmal AF (Table 1). Major embolism was not recorded during the follow-up period. The cumulative period of observation was 356 months in the 20 patients who were originally in sinus rhythm. None of the patients developed chronic AF, but one experienced paroxysmal AF. The arrhythmia was confirmed during admission to another hospital. Three patients had a history of episodes of mild palpitations leading to ECG monitoring during admission, and Holter monitoring. However, AF was not revealed.
ATRIAL FIBRILLATION AND LEFT ATRIAL ENLARGEMENT
On the basis of the findings in the group of 2 0 patients in sinus rhythm who completed the followup, the risk of developing AF could be calculated as 1 x 121356, i.e. 3 % per year. Taking into account the observations on the 15 above-mentioned patients who died before follow-up, the prospective risk of developing AF could be estimated to be 2 x 12/455, i.e. 5 % per year. The medication received by the 35 patients who were included in this calculation is shown in Table 2. An analysis of the change of the left atrial dimension from inclusion to follow-up was performed in the 40 patients who completed the study. For the 2 0 patients in sinus rhythm at the first admission, the LA dimension increased by 1 ( - 13 to 9 ) mm during a median follow-up period of 2 0 months (Table 1). The LA dimension increased by 2 ( - 8 to 12) mm in the 1 6 patients with chronic AF ( P > 0.05). The LA dimension at follow-up did not differ significantly from the baseline value either in the group of patients in sinus rhythm, or in those with chronic AF (P > 0.05). Three of the four patients with paroxysmal AF at the first examination sustained sinus rhythm during follow-up. The remaining patient experienced frequent attacks of AF. The LA dimension in the patients with paroxysmal AF was 4 8 ( 4 7 4 9 ) mm at the first examination and 4 6 (3952) mm at follow-up.
Discussion According to a common theory, heart disease with a haemodynamic burden on LA initially produces atrial dilation, which in turn increases the risk of development of AF. Once AF occurs, LA dilation might progress due to either progressive heart disease, loss of the atrial systole, or both factors [2]. The widespread use of echocardiography and the significance of AF [8] indicates that it is relevant to characterize the prospective risk of AF in patients with LA enlargement. A high incidence of the arrhythmia in patients with LA dilation might warrant prophylactic antiarrhythmic and anticoagulant therapy [9]. However, in this prospective study of patients with definite LA enlargement, the incidence of new AF did not exceed 5 % per year. Thus definite LA dilation in the M-mode echocardiogram cannot be considered to be an immediate precursor of clinically significant AF. Clinically silent paroxysms of AF may have been overlooked, but paroxysmal AF is less frequently complicated by embolism than persistent AF [9], and
255
the arrhythmia is usually revealed if heart failure develops. The medication of our patients may have protected them against AF. However, a specific antiarrhythmic effect was not intended in the patients in sinus rhythm. Digoxin, calcium-blockers and beta-blockers were only administered when necessary to relieve heart failure, angina pectoris and hypertension. Furthermore, almost 2 5 % of the patients in sinus rhythm were receiving no medical treatment (Table 2). In patients with AF, the medication was given in accordance with common clinical practice, and an effect of digoxin, calcium and beta-blockers on heart size cannot be excluded. As in other studies of patients with LA dilation, there was a high prevalence of AF (22 of 58 patients, i.e. 38 %) at the time of inclusion in the study [ l ,21. Thus the rare occurrence of new AF might be due to the fact that the majority of patients prone to develop AF had already passed the degree of LA dilation associated with a high risk of AF. Other patients may withstand LA dilation without development of AF, due to a high threshold for development of atrial conduction defects [lo, 111. Admittedly, LA geometry and size are not completely characterized by a single dimension that is uncorrected for body surface area [I 2 , 131. However, in daily clinical practice the evaluation and management of patients is commonly dependent on the absolute chamber dimensions calculated by M-mode echocardiography [14]. Our definition of LA enlargement was selected in order to obtain a study population which, in most centres, would be considered to have definite LA dilation. The calculation of the LA index (Table 1) confirmed the presence of true LA enlargement [ 151. The left atrial dimension may exhibit major dynamic increases and decreases in relation to haemodynamic changes [16]. Our data on the change in left atrial dimension from inclusion to follow-up showed considerable positive and negative variation in both groups of patients. This variation reflects anatomical changes and intra- and interobserver variability. However, blinding of the echocardiographers with respect to the clinical course and the result of the initial echocardiography eliminated the risk of systematic bias. Our finding that chronic AF does not lead to further significant dilation of the left atrium is not in complete agreement with recent studies [3-51. However, in the present study the patients were 5-10
256
J. S. ANDERSEN et al.
years younger, and the LA dimension at the initial examination was larger than in previously published studies [3-51. Our investigation included hospitalized patients and, although they represented a wide spectrum of conditions (Table l ) , their common feature, a left atrial dimension of 4.5 cm, appeared to be very ominous. Fifteen of the original 82 patients died during the initial admission, and 18 patients died during follow-up, in the majority of cases from heart failure, leading to an overall mortality of 40%. Finally, in contrast to previously published investigations, our study included a control group of patients in sinus rhythm, and blinding of the echocardiographer with respect to history and previous data at entry to the study. In conclusion, LA dilation may still represent both a cause and a consequence of AF. However, in a selected group of patients, our study demonstrated that definite LA enlargement in patients in sinus rhythm was not a marker of impending AF. Similarly, AF per se did not appear to result in further significant LA enlargement in patients who had already developed definite dilation of the left atrium.
=-
References 1 Probst P. Goldschlager N. Selzer A. Left atrial size and atrial fibrillation in mitral stenosis. Circulation 1 9 7 3 : 48: 1282-7. 2 Henry WL. Morganroth J. Pearlman AS et a / . Relation between echocardiographically determined left atrial size and atrial fibrillation. Circulation 1 9 7 6 ; 5 3 : 273-9. 3 Petersen P. Kastrup J. Brinch K. Codtfredsen J. Boysen C. Relation between left atrial dimension and duration of atrial fibrillation. Am j Cardiol 1 9 8 7 : 60: 3 8 2 4 . 4 Sanfilippo AJ. Abascal VM. Sheehan M et a/. Left atrial enlargement as a consequence of atrial fibrillation: a
prospective echocardiographic study (abstract). At11 Coll Cardiol 1 9 8 9 : 1 3 : 206A. 5 Sosa-Suarez. C. Iampert S. Graboys TB, Ravid S. Lown B. Changes in left atrial size due to chronic atrial tibrillation (abstract). ] A m Coll Cardiol 1 9 8 9 ; 13: 206A. 6 Egeblad H. Berning J. Echocardiography. Registration technique, indications and yield in clinical practice. Eur ] Radiol 1 9 8 3 ; 3 (SUPPI. 1): 273-80. 7 Sahn DJ. DeMaria A. Kisslo 1. Weyman A. Recommendations regarding quantitation in M-mode echocardiography : results of a survey of echocardiographic measurements. Circulation 1 9 7 8 ; 58: 1072-83. 8 Petersen P, Godtfredsen J. Atrial fibrillation - a review of course and prognosis. Acta Med Scand 1 9 8 4 : 2 1 6 : 5-9. 9 Petersen P. Boysen G. Codtfredsen I. Andersen El). Andersen
B. Placebo-controlled, randomised trial of warfarin and aspirin for prevention of thromboembolic complications in chronic atrial fibrillation. Lancet 1 9 8 9 : i: 175-9. 1 0 Robitaille CA. Phillips JH. An analysis of the P-wave in patients with transient benign atrial fibrillation. Dis Chest 1 9 6 7 : 52: 806-12. 11 Josephson ME, Kastor JA. Morganroth J. Electrocardiographic left atrial enlargement. Electrophysiologic. echocardiographic and hemodynamiccorrelates. ArnjCardioll977: 39: 967-71. 12 Lopefido F. Pennestri F. Digaetano A el a/. Assessment of left atrial dimensions by cross-sectional echocardiography in patients with mitral valve disease. Br Heart ] 1 9 8 3 : 5 0 : 570-78. 13 Lemire F. Tajik AJ. Hagler DJ.Asymmetric left atrial enlargement. Chest 1976; 6 9 : 779-81. 1 4 Hoglund C. Rosenhamer G. Echocardiographic left atrial dimension as a predictor of maintaining sinus rhythm after conversion of atrial fibrillation. Acta Med Scand 1985 : 2 1 7: 4 1 1-5. 15 Hirata T. W o k SB. Popp RL. Helmen CH. Feigenbaum H. Estimation of left atrial size using ultrasound. Am Heart j 1 9 6 9 : 78: 43-52. 16 Feigenbaum H. Echocardiography, 3rd edn. Philadelphia : Lea and Febiger. 1981 : 172-6.
Received 1 7 June 1990, accepted 6 September 1990. Correspondence: Jergen Steen Andersen. Toftckrersvcj 135, 2 8 6 0 Seborg. Denmark.
ADONIS
09 5468209 100044 7
Atrial fibrillation and left atrial enlargement : cause or effect? J. S. ANDERSEN, H. EGEBLAD, U. ABILDGAARD, J. ALDERSHVILE & J. GODTFREDSEN From the Division of Cardiology. Medical Department F . Herlev Hospital. University Hospital of Copenhagen. Denmark
Abstract. Andersen IS, Egeblad H.Abildgaard U, Aldershvile J, Godtfredsen J (Division of Cardiology, Medical Department F. Herlev Hospital, University Hospital of Copenhagen. Denmark). Atrial fibrillation and left atrial enlargement: cause or effect Z Journal oJlnterna1 Medicine 1991; 229: 253-256. In a blinded controlled study, 58 consecutive patients with definite left atrial enlargement (M-mode dimension of at least 45 mm) were followed up after 1-2 years. The aim of the study was to examine the following: (a) the prospective risk of developing atrial fibrillation (AF); and (b) the effect of the heart rhythm on the left atrial size. Of 36 patients in sinus rhythm, one developed paroxysmal AF and one developed persistent AF during a median follow-up period of 20 months. Thus the incidence of new AF was 5 % per year. Eighteen patients died before scheduled echocardiographic follow-up. but in the remaining subjects the left atrial dimension did not change significantly : the median increment was 1 mm in 20 patients who sustained sinus rhythm vs. 2 mm in 16 patients with chronic AF (P > 0.05). Although left atrial dilation may cause AF and vice versa, this study demonstrated that the incidence of new AF is low, despite the fact that the left atrial dimension is substantially increased. Similarly, AF per se does not appear to have any major impact on the left atrial dimension. K e y w o r d s : atrial dilation, atrial fibrillation, echocardiography.
Introduction The association between atrial fibrillation (AF) and dilation of the left atrium (LA) is well recognized, although the causal relationship between AF and LA dilation remains controversial [l-51. In this study, the risk of developing AF was examined prospectively in patients with LA dilation and sinus rhythm. In addition, an analysis of the effect of the heart rhythm on LA size was performed.
Patients and methods The study was based on 739 consecutive echocardiographic examinations performed on patients who had been admitted to a district hospital over a period of 18 months. The examinations were carried out by four senior cardiologists who were experienced in echocardiography. All examinations were performed
for diagnostic work-up in accordance with generally accepted indications [ 6 ] .Eighty-two of the patients had definite LA dilation, here defined as an LA dimension of > 45 mm recorded by 2D-guided M-mode echocardiography [ 71. These patients were eligible for inclusion in the study, but 1 5 subjects who died during admission were excluded due to lack of follow-up data. The cause of death was heart failure in the majority of cases, although some patients succumbed because of pneumonia, azotaemia, malignant diseases and malignant arrhythmias. An additional nine patients were excluded, of whom two refused to participate in the follow-up, and seven underwent interventions or other significant change in the basic condition, with a consequent reduction of left atrial strain (e.g. valve replacement, birth after pre-eclampsia, haemodialysis). The remaining 58 patients were included in the study for follow-up after 1-2 years. At the follow-up, physical 253
254
J. S. ANDERSEN et al.
Table 1 . Characteristics of the 40 patients who completed follow-up: data were recorded at entry to the study Sinus rhythm ( n = 2 0 ) ( 1 5 M 5F)
Atrial fibrillation (n=20)(11M9F)
P-value
Left atrial dimension (mm) Left atrial index (mm/m') Functional class (NYHA) Follow-up period (months)
5 5 (22-80) 4 8 (46-54) 25 (20-32) I1 (1-111) 2 0 ( 10-24)
59 (43-77) 50 (46-67) 2 6 (21-38) 111 (I-IV) 21 ( 1 1-27)
NS NS NS NS NS
Cardiac condition Primary valve disease Acute myocardial infarction Cardiomyopathy Hypertensive heart disease Chronic ischaemic heart disease Congenital heart disease
7 5 4 2 2 0
Age ( y e a 4
Median values and range are listed ( P > 0.05 for all comparisons).
Table 2. Medical treatment of patients in sinus rhythm at entry to the study n No medication Digoxin and diuretics Digoxin. calcium-blockers and diuretics Digoxin. calcium-blockers, diuretics and beta-blockers Digoxin Calcium-blockers and diuretics Beta-blockers and diuretics Diuretics
8 10 10 1
Total
35.
1
2 1
2
'The 35 patients include 2 0 subjects who completed follow-up and 1 5 patients who died during follow-up, and for whom an BCG was recorded after the initial examination.
examination, ECG and echocardiography were performed. Echocardiography was performed without knowledge of the patient's history or the results of the previous echocardiographic examination. If the patients's history included spells of palpitations, or otherwise suggested paroxysmal atrial fibrillation, information was obtained from general practitioners, other hospitals and 24-h Holter monitoring. Thyroid status was determined in patients with AF, and all were found to have normal thyroid function. During the follow-up period, the patients were treated medically in accordance with their basic heart disease (Tables 1 and 2).
Statistics
.
Rank-sum tests for paired or unpaired samples were used when appropriate.
Results Eighteen of the 58 patients died before the follow-up examination. Two of the 1 8 patients had chronic AF, and sixteen were in sinus rhythm at the original admission. Echocardiographic follow-up data were not available for this group. However, 1 5 of the 16 patients who were originally in sinus rhythm had one or more ECG recordings performed after the first admission. The median observation period (with range) from the original admission to the date of the most recent ECG was 5 (1-19) months. and the cumulative observation time was 99 months in these patients. One of the patients developed persistent AP. The causes of death in the 18 patients were acute myocardial infarction, heart or multiorgan failure, and cancer. However, the definite cause of death was unknown in seven patients who died outside hospital; autopsy was not performed in these cases. Forty patients completed the follow-up, which was performed after 2 1 (10-2 7) months. At the original admission, 20 patients were in sinus rhythm, none of whom had a history of previous AF. Of the remaining 20 patients, 1 6 had chronic and four had paroxysmal AF (Table 1). Major embolism was not recorded during the follow-up period. The cumulative period of observation was 356 months in the 20 patients who were originally in sinus rhythm. None of the patients developed chronic AF, but one experienced paroxysmal AF. The arrhythmia was confirmed during admission to another hospital. Three patients had a history of episodes of mild palpitations leading to ECG monitoring during admission, and Holter monitoring. However, AF was not revealed.
ATRIAL FIBRILLATION AND LEFT ATRIAL ENLARGEMENT
On the basis of the findings in the group of 2 0 patients in sinus rhythm who completed the followup, the risk of developing AF could be calculated as 1 x 121356, i.e. 3 % per year. Taking into account the observations on the 15 above-mentioned patients who died before follow-up, the prospective risk of developing AF could be estimated to be 2 x 12/455, i.e. 5 % per year. The medication received by the 35 patients who were included in this calculation is shown in Table 2. An analysis of the change of the left atrial dimension from inclusion to follow-up was performed in the 40 patients who completed the study. For the 2 0 patients in sinus rhythm at the first admission, the LA dimension increased by 1 ( - 13 to 9 ) mm during a median follow-up period of 2 0 months (Table 1). The LA dimension increased by 2 ( - 8 to 12) mm in the 1 6 patients with chronic AF ( P > 0.05). The LA dimension at follow-up did not differ significantly from the baseline value either in the group of patients in sinus rhythm, or in those with chronic AF (P > 0.05). Three of the four patients with paroxysmal AF at the first examination sustained sinus rhythm during follow-up. The remaining patient experienced frequent attacks of AF. The LA dimension in the patients with paroxysmal AF was 4 8 ( 4 7 4 9 ) mm at the first examination and 4 6 (3952) mm at follow-up.
Discussion According to a common theory, heart disease with a haemodynamic burden on LA initially produces atrial dilation, which in turn increases the risk of development of AF. Once AF occurs, LA dilation might progress due to either progressive heart disease, loss of the atrial systole, or both factors [2]. The widespread use of echocardiography and the significance of AF [8] indicates that it is relevant to characterize the prospective risk of AF in patients with LA enlargement. A high incidence of the arrhythmia in patients with LA dilation might warrant prophylactic antiarrhythmic and anticoagulant therapy [9]. However, in this prospective study of patients with definite LA enlargement, the incidence of new AF did not exceed 5 % per year. Thus definite LA dilation in the M-mode echocardiogram cannot be considered to be an immediate precursor of clinically significant AF. Clinically silent paroxysms of AF may have been overlooked, but paroxysmal AF is less frequently complicated by embolism than persistent AF [9], and
255
the arrhythmia is usually revealed if heart failure develops. The medication of our patients may have protected them against AF. However, a specific antiarrhythmic effect was not intended in the patients in sinus rhythm. Digoxin, calcium-blockers and beta-blockers were only administered when necessary to relieve heart failure, angina pectoris and hypertension. Furthermore, almost 2 5 % of the patients in sinus rhythm were receiving no medical treatment (Table 2). In patients with AF, the medication was given in accordance with common clinical practice, and an effect of digoxin, calcium and beta-blockers on heart size cannot be excluded. As in other studies of patients with LA dilation, there was a high prevalence of AF (22 of 58 patients, i.e. 38 %) at the time of inclusion in the study [ l ,21. Thus the rare occurrence of new AF might be due to the fact that the majority of patients prone to develop AF had already passed the degree of LA dilation associated with a high risk of AF. Other patients may withstand LA dilation without development of AF, due to a high threshold for development of atrial conduction defects [lo, 111. Admittedly, LA geometry and size are not completely characterized by a single dimension that is uncorrected for body surface area [I 2 , 131. However, in daily clinical practice the evaluation and management of patients is commonly dependent on the absolute chamber dimensions calculated by M-mode echocardiography [14]. Our definition of LA enlargement was selected in order to obtain a study population which, in most centres, would be considered to have definite LA dilation. The calculation of the LA index (Table 1) confirmed the presence of true LA enlargement [ 151. The left atrial dimension may exhibit major dynamic increases and decreases in relation to haemodynamic changes [16]. Our data on the change in left atrial dimension from inclusion to follow-up showed considerable positive and negative variation in both groups of patients. This variation reflects anatomical changes and intra- and interobserver variability. However, blinding of the echocardiographers with respect to the clinical course and the result of the initial echocardiography eliminated the risk of systematic bias. Our finding that chronic AF does not lead to further significant dilation of the left atrium is not in complete agreement with recent studies [3-51. However, in the present study the patients were 5-10
256
J. S. ANDERSEN et al.
years younger, and the LA dimension at the initial examination was larger than in previously published studies [3-51. Our investigation included hospitalized patients and, although they represented a wide spectrum of conditions (Table l ) , their common feature, a left atrial dimension of 4.5 cm, appeared to be very ominous. Fifteen of the original 82 patients died during the initial admission, and 18 patients died during follow-up, in the majority of cases from heart failure, leading to an overall mortality of 40%. Finally, in contrast to previously published investigations, our study included a control group of patients in sinus rhythm, and blinding of the echocardiographer with respect to history and previous data at entry to the study. In conclusion, LA dilation may still represent both a cause and a consequence of AF. However, in a selected group of patients, our study demonstrated that definite LA enlargement in patients in sinus rhythm was not a marker of impending AF. Similarly, AF per se did not appear to result in further significant LA enlargement in patients who had already developed definite dilation of the left atrium.
=-
References 1 Probst P. Goldschlager N. Selzer A. Left atrial size and atrial fibrillation in mitral stenosis. Circulation 1 9 7 3 : 48: 1282-7. 2 Henry WL. Morganroth J. Pearlman AS et a / . Relation between echocardiographically determined left atrial size and atrial fibrillation. Circulation 1 9 7 6 ; 5 3 : 273-9. 3 Petersen P. Kastrup J. Brinch K. Codtfredsen J. Boysen C. Relation between left atrial dimension and duration of atrial fibrillation. Am j Cardiol 1 9 8 7 : 60: 3 8 2 4 . 4 Sanfilippo AJ. Abascal VM. Sheehan M et a/. Left atrial enlargement as a consequence of atrial fibrillation: a
prospective echocardiographic study (abstract). At11 Coll Cardiol 1 9 8 9 : 1 3 : 206A. 5 Sosa-Suarez. C. Iampert S. Graboys TB, Ravid S. Lown B. Changes in left atrial size due to chronic atrial tibrillation (abstract). ] A m Coll Cardiol 1 9 8 9 ; 13: 206A. 6 Egeblad H. Berning J. Echocardiography. Registration technique, indications and yield in clinical practice. Eur ] Radiol 1 9 8 3 ; 3 (SUPPI. 1): 273-80. 7 Sahn DJ. DeMaria A. Kisslo 1. Weyman A. Recommendations regarding quantitation in M-mode echocardiography : results of a survey of echocardiographic measurements. Circulation 1 9 7 8 ; 58: 1072-83. 8 Petersen P, Godtfredsen J. Atrial fibrillation - a review of course and prognosis. Acta Med Scand 1 9 8 4 : 2 1 6 : 5-9. 9 Petersen P. Boysen G. Codtfredsen I. Andersen El). Andersen
B. Placebo-controlled, randomised trial of warfarin and aspirin for prevention of thromboembolic complications in chronic atrial fibrillation. Lancet 1 9 8 9 : i: 175-9. 1 0 Robitaille CA. Phillips JH. An analysis of the P-wave in patients with transient benign atrial fibrillation. Dis Chest 1 9 6 7 : 52: 806-12. 11 Josephson ME, Kastor JA. Morganroth J. Electrocardiographic left atrial enlargement. Electrophysiologic. echocardiographic and hemodynamiccorrelates. ArnjCardioll977: 39: 967-71. 12 Lopefido F. Pennestri F. Digaetano A el a/. Assessment of left atrial dimensions by cross-sectional echocardiography in patients with mitral valve disease. Br Heart ] 1 9 8 3 : 5 0 : 570-78. 13 Lemire F. Tajik AJ. Hagler DJ.Asymmetric left atrial enlargement. Chest 1976; 6 9 : 779-81. 1 4 Hoglund C. Rosenhamer G. Echocardiographic left atrial dimension as a predictor of maintaining sinus rhythm after conversion of atrial fibrillation. Acta Med Scand 1985 : 2 1 7: 4 1 1-5. 15 Hirata T. W o k SB. Popp RL. Helmen CH. Feigenbaum H. Estimation of left atrial size using ultrasound. Am Heart j 1 9 6 9 : 78: 43-52. 16 Feigenbaum H. Echocardiography, 3rd edn. Philadelphia : Lea and Febiger. 1981 : 172-6.
Received 1 7 June 1990, accepted 6 September 1990. Correspondence: Jergen Steen Andersen. Toftckrersvcj 135, 2 8 6 0 Seborg. Denmark.
