Combined Ambulatory Electroencephalographic and Electrocardiographic Recordings for Evaluation of Syncope Lou-Anne M. Beauregard, MD, Rosemary Fabiszewski, BSN, Caprice H. Black, BS, Barbara Lightfoot, AB, Paul L. Schraeder, MD, Travis Toly, MD, and Harvey L. Waxman, MD
Evaluation of patients with syncope often includes a battery of noninvasive tests. In this study, 45 patients (26 with suspected neurologic and 19 with suspected cardiac syncope) were evaluated with simultaneous 24-hour electroencephalographic (EEG) and P-channel electrocardiographic (ECG) recordings. Isolated cardiac rhythm abnormalities were noted in 21 patients, but none of these was symptomatic and no definitive arrhythmias occurred. Isolated EEG abnormalities were noted in 11 patients, 5 of whom had EEG abnormalities consistent with seizure disorders. Simultaneous EEG and ECG abnormalities were seen in 4 patients. In 2 cases, a previously unsuspected etiology for syncope was found: seizures in 1 patient with heart disease, and sinus pauses in another thought to have a seizure disorder. Thus, combined ambulatory EEG/ECG monitoring may prove useful in the evaluatlon of some patients with syncope. (Am J Cardiol 1991;68:1067-1072)
yncope is a disorder that frequently involves both cardiac and neurologic workups. Patient history may direct the evaluation if featuressuggestinga cardiac rhythm or seizure disorder are elicited. However, etiology is not clearly evident.’ As a result, patients have both cardiac and neurologic noninvasive assessmentswith low yield2 and frequent repetition of studies. Recently, a technique of recording continuous ambulatory electroencephalographic (EEG) information using a portable cassetterecorder was developed.3The ambulatory electroencephalogramrecords 7 leads of EEG information and 1 lead of electrocardiographic (ECG) information.4 Despite its limitations, investigators have found a higher yield of transient neurologic eventsin patients with clinical epilepsy but nondiagnostic electroencephalographyat rest.5-7 This study evaluated the usefulnessof ambulatory EEG monitoring in the diagnosisof syncope.The combination of 2-channel Holter and ambulatory EEG recording was used to enhance detection of arrhythmias. It was hoped that use of these tools in combination might enhance yield from noninvasive techniques.
S
METHODS
From the Divisions of Cardiology and Neurology, Department of Medicine, Cooper Hospital/University Medical Center, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School at Camden, Camden, New Jersey. This study was supported in part by Grant No. 864309 from the American Heart Association, New Jersey Affiliate, Audubon, New Jersey. Manuscript received April 29, 1991; revised manuscript received and accepted June 24, 1991. Address for reprints: Lou-Anne M. Beauregard, MD, Division of Cardiology, Cooper Hospital/University Medical Center, One Cooper Plaza, Camden, New Jersey 08103.
Patients were recruited from among those undergoing evaluation for syncopeat Cooper Hospital/University Medical Center from June 1986 to January 1989. Patients included those admitted to the Cardiology or Neurology Service with syncope. Some patients had witnessedevents, and history was used to stratify whether a seizure or cardiac arrhythmia was the likely cause.Neurological evaluation included careful examination and electroencephalographyat rest in most patients, and all patients underwent Holter monitoring either separatelyor as part of this study. A description of the procedure was provided to each patient, and consent was obtained. The Oxford Medilog 9000 ambulatory EEG recorder was used, with 7 leads of EEG information and 1 ECG channel. A modified Vi lead was recordedas well as a standard adult montage consisting of 4 temporal, 2 frontal and 1 central lead for electroencephalography.An additional 2 ECG channels were recordedusing a modified lead I and Vs on an ambulaAMBULATORY EEG AND ECG FOR SYNCOPE
1067
TABLE I
Patient
Characteristics
and Ambulatory
The patients were divided into 2 groups prospectively: those who were thought to have a high likelihood of neurologic events or seizure disorders (neurologic syncope); and those who were thought to have a high likelihood of syncoperelated to cardiac arrhythmias, orthostatic hypotension or other cardiovascular causes(cardiac syncope), based on history and physical data.
Monitoring
Results
Mean age (range) Men/women Concurrent illnesses Organic heart disease Systemic hypertension Cerebrovascular accident Subdural hematoma Previous seizure history None ECG findings Supraventricular tachycardias Pauses Nonsustained ventricular tachycardia No abnormalities EEG findings Focal abnormalities Nonspecific findings Normal
Neurologic Syncope (n = 26)
Cardiac Syncope (n = 19)
38 (1 l-87) 12114
60 (25-85) 1019
0 2 0
7 5 1
2 4 17
0 0 8
2
4
2 0
0 2
11
7
5 2 19
1 4 14
ECG= electrocardiographic; EEC = electroencephalographic.
tory ECG (Holter) monitor. Diary entries were made for both EEG and ECG monitors by the patients. Ambulatory ECG and EEG data were analyzed separately. The ambulatory electrocardiogram was scannedusing the CardioData Mark IV digital Holter system with 6-secondstrips obtained at 25 mm/set for symptomatic events or relevant cardiac arrhythmias. Ambulatory ECG information was interpreted by 1 cardiologist (LAB). Ambulatory EEG tapes were scannedat 20 to 60X real time, and hard copy was displayed on standard EEG paper at 30 mm/set. Paper recordings of the data were reviewed by 1 neurologist (PLS). Symptomatic eventswere noted and correlated with ECG abnormalities. EEG abnormalities were defined as focal or nonfocal slowing, spike and wave complexesconsistent with seizure activity, or other nonspecific abnormalities, such as 19or 6 waves, inappropriate for age or state of alertness,but not definitely consistent with seizure activity. ECG abnormalities included sinus bradycardia 2 seconds.Unless these events were associatedwith symptoms,they were not considereddiagnostic of a cause of syncope. Combined EEG and ECG abnormalities were said to exist when the patient experiencedboth an EEG abnormality and a significant cardiac arrhythmia, as described previously, at the sametime. These eventswere correlated with diary entries to assessthe presenceor absenceof symptoms. 1068
THE AMERICAN
JOURNAL
OF CARDIOLOGY
VOLUME
68
RESULTS There were 26 patients (average age 38 years) with suspectedneurologic and 19 (average age 60) with suspected cardiac syncope(p = not significant) (Table I). Gender distribution was similar. Concomitant illnesses included hypertension, valvular heart disease,cerebrovascular accident, subdural hematoma and previous seizure disorder. Eighteen patients had no cardiac arrhythmias detected by ambulatory monitoring. In the remaining patients, one 1l-year-old child had heart rates as low as 48, and 2 adult patients had heart rates
Evaluation of patients with syncope often includes a battery of noninvasive tests. In this study, 45 patients (26 with suspected neurologic and 19 with suspected cardiac syncope) were evaluated with simultaneous 24-hour electroencephalographic (EEG) and P-channel electrocardiographic (ECG) recordings. Isolated cardiac rhythm abnormalities were noted in 21 patients, but none of these was symptomatic and no definitive arrhythmias occurred. Isolated EEG abnormalities were noted in 11 patients, 5 of whom had EEG abnormalities consistent with seizure disorders. Simultaneous EEG and ECG abnormalities were seen in 4 patients. In 2 cases, a previously unsuspected etiology for syncope was found: seizures in 1 patient with heart disease, and sinus pauses in another thought to have a seizure disorder. Thus, combined ambulatory EEG/ECG monitoring may prove useful in the evaluatlon of some patients with syncope. (Am J Cardiol 1991;68:1067-1072)
yncope is a disorder that frequently involves both cardiac and neurologic workups. Patient history may direct the evaluation if featuressuggestinga cardiac rhythm or seizure disorder are elicited. However, etiology is not clearly evident.’ As a result, patients have both cardiac and neurologic noninvasive assessmentswith low yield2 and frequent repetition of studies. Recently, a technique of recording continuous ambulatory electroencephalographic (EEG) information using a portable cassetterecorder was developed.3The ambulatory electroencephalogramrecords 7 leads of EEG information and 1 lead of electrocardiographic (ECG) information.4 Despite its limitations, investigators have found a higher yield of transient neurologic eventsin patients with clinical epilepsy but nondiagnostic electroencephalographyat rest.5-7 This study evaluated the usefulnessof ambulatory EEG monitoring in the diagnosisof syncope.The combination of 2-channel Holter and ambulatory EEG recording was used to enhance detection of arrhythmias. It was hoped that use of these tools in combination might enhance yield from noninvasive techniques.
S
METHODS
From the Divisions of Cardiology and Neurology, Department of Medicine, Cooper Hospital/University Medical Center, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School at Camden, Camden, New Jersey. This study was supported in part by Grant No. 864309 from the American Heart Association, New Jersey Affiliate, Audubon, New Jersey. Manuscript received April 29, 1991; revised manuscript received and accepted June 24, 1991. Address for reprints: Lou-Anne M. Beauregard, MD, Division of Cardiology, Cooper Hospital/University Medical Center, One Cooper Plaza, Camden, New Jersey 08103.
Patients were recruited from among those undergoing evaluation for syncopeat Cooper Hospital/University Medical Center from June 1986 to January 1989. Patients included those admitted to the Cardiology or Neurology Service with syncope. Some patients had witnessedevents, and history was used to stratify whether a seizure or cardiac arrhythmia was the likely cause.Neurological evaluation included careful examination and electroencephalographyat rest in most patients, and all patients underwent Holter monitoring either separatelyor as part of this study. A description of the procedure was provided to each patient, and consent was obtained. The Oxford Medilog 9000 ambulatory EEG recorder was used, with 7 leads of EEG information and 1 ECG channel. A modified Vi lead was recordedas well as a standard adult montage consisting of 4 temporal, 2 frontal and 1 central lead for electroencephalography.An additional 2 ECG channels were recordedusing a modified lead I and Vs on an ambulaAMBULATORY EEG AND ECG FOR SYNCOPE
1067
TABLE I
Patient
Characteristics
and Ambulatory
The patients were divided into 2 groups prospectively: those who were thought to have a high likelihood of neurologic events or seizure disorders (neurologic syncope); and those who were thought to have a high likelihood of syncoperelated to cardiac arrhythmias, orthostatic hypotension or other cardiovascular causes(cardiac syncope), based on history and physical data.
Monitoring
Results
Mean age (range) Men/women Concurrent illnesses Organic heart disease Systemic hypertension Cerebrovascular accident Subdural hematoma Previous seizure history None ECG findings Supraventricular tachycardias Pauses Nonsustained ventricular tachycardia No abnormalities EEG findings Focal abnormalities Nonspecific findings Normal
Neurologic Syncope (n = 26)
Cardiac Syncope (n = 19)
38 (1 l-87) 12114
60 (25-85) 1019
0 2 0
7 5 1
2 4 17
0 0 8
2
4
2 0
0 2
11
7
5 2 19
1 4 14
ECG= electrocardiographic; EEC = electroencephalographic.
tory ECG (Holter) monitor. Diary entries were made for both EEG and ECG monitors by the patients. Ambulatory ECG and EEG data were analyzed separately. The ambulatory electrocardiogram was scannedusing the CardioData Mark IV digital Holter system with 6-secondstrips obtained at 25 mm/set for symptomatic events or relevant cardiac arrhythmias. Ambulatory ECG information was interpreted by 1 cardiologist (LAB). Ambulatory EEG tapes were scannedat 20 to 60X real time, and hard copy was displayed on standard EEG paper at 30 mm/set. Paper recordings of the data were reviewed by 1 neurologist (PLS). Symptomatic eventswere noted and correlated with ECG abnormalities. EEG abnormalities were defined as focal or nonfocal slowing, spike and wave complexesconsistent with seizure activity, or other nonspecific abnormalities, such as 19or 6 waves, inappropriate for age or state of alertness,but not definitely consistent with seizure activity. ECG abnormalities included sinus bradycardia 2 seconds.Unless these events were associatedwith symptoms,they were not considereddiagnostic of a cause of syncope. Combined EEG and ECG abnormalities were said to exist when the patient experiencedboth an EEG abnormality and a significant cardiac arrhythmia, as described previously, at the sametime. These eventswere correlated with diary entries to assessthe presenceor absenceof symptoms. 1068
THE AMERICAN
JOURNAL
OF CARDIOLOGY
VOLUME
68
RESULTS There were 26 patients (average age 38 years) with suspectedneurologic and 19 (average age 60) with suspected cardiac syncope(p = not significant) (Table I). Gender distribution was similar. Concomitant illnesses included hypertension, valvular heart disease,cerebrovascular accident, subdural hematoma and previous seizure disorder. Eighteen patients had no cardiac arrhythmias detected by ambulatory monitoring. In the remaining patients, one 1l-year-old child had heart rates as low as 48, and 2 adult patients had heart rates
