Electrocardiographic Observation Simultaneously with Stimulation of Thalamus and and Thalamic Coagulation (Is There a Neurocardiac Relationship to the Thalamus and Globus Pallidus?)

J. CLAYTONDAVIE, M.D. Branch of Surgical Neurology, National Institute of Neurological Diseases and Blindness, National Institutes of Health, Department of Health, Education, and Welfare, U. S. Public Health Service, Bethesda, Maryland

HE currently employed method of and, if accepted, their anatomical positions were therapy for Parkinson s disease in- determined by measurements in a three-direc- tional plane and correlated with anatomical posi- T volves stimulation and coagulation of tions from a stereotaxic atlas of the . 3 the thalamic nucleus ventralis lateralis and Electrodes were inserted under local anesthesia globus pallidus. Since stimulation of a related and, ~ to 5 days later, electrical stimulation at structure, the hypothalamus, has been shown different levels of each electrode was performed. to produce pronounced changes in atrial and A routine l~-lead electrocardiogram was ob- tained pre- and postoperatively. Limb lead II was ventrieular rhythm, it becomes important to recorded during the period of stimulation and know if similar effects would result from the immediately following thalamic coagulation. surgical procedure used to alleviate the signs Because of interference, an electrocardiogram and symptoms of Parkinson's disease. Such could not be recorded at the time of coagulation an investigation assumes more immediate Results importance since the majority of patients afflicted with this disorder are elderly and Three patients were studied. A total of 14 have atherosclerosis of varying severity. If, subcortical areas were stimulated for a pe- for instance, through sympathetic or para- riod of 5 to ~0 sec.; these are listed in Table 1. sympathetic activation, these procedures The anatomical structures noted in Table 1 would tend to affect myocardial function through the changes in cardiac rhythm, it TABLE 1 would be of advantage to know this and ap- Anatomic structures stimulated in 3 patients ply such knowledge in the total management while simultaneously recording the electrocardiogram* of the patient. This study was undertaken to determine the presence or absence of such Subcortieal areas stimulated for 5-~0 sec. with a adverse effects of this neurosurgical proce- unidirectional wave of ~.5 msec. pulse length, dure. 60 c./sec, and peak of 5-15 mA. 1. Vcntralis intermedialis externa Technic ~. Ventralis oralis anterior 3. Radiatio principalis Using the stercotaxic technic of Van Buren and 4. Reticularis polaris Maccubbin 4 with the anterior and posterior com- 5. Ventralis oralis posterior missures as landmarks, demonstrated during air 6. Zona incerta encephalography, the positions of the ventral 7. Internal capsula, genu lateral thalamus and globus pallidus were calcu- 8. Internal capsula, anterior limb 9. Pallidus I lated. A stimulating electrode was inserted into 10. Pallidus II the estimated position of the globus pallidus. A ll. Lateral caudate second stimulating electrode with a coagulating le. Deep frontal white metal tip was inserted into the estimated position 13. Mid-frontal white of the nucleus ventralis lateralis of the thalamus. 14. Superficial frontal white These positions were checked radiographically *These are correlated areas and do not represent Received for publication October ~5, 196~. specific anatomically confirmed structures. 387 388 J. Clayton Davie represent in general the areas of stimulations. with a variety of intensities and frequencies It is well recognized that the correlation of during 165 electrocardiographic tracings. radiographic positions of the electrodes with The only change of possible significance was an anatomical atlas is not absolutely reliable. an alteration in the amplitude of the QRS An approximate total of 165 different electro- complex. Even though it may be artifact, it cardiographic tracings were obtained in cannot be excluded totally. these 3 patients. In all electrocardiograms Over the past decade, a large number of obtained there were no changes in rate, patients have undergone stimulation and rhythm, or mode of excitation. In addition, destruction of the in an effort to no alterations in the duration of the QRS or reduce or abolish the tremors of Parkinson's in the P-R or QT intervals could be de- disease. Even though a vast amount of tected in any of the tracings obtained from knowledge has accumulated as a result of the 3 patients studied. these procedures, the cardiovascular effects In 1 patient during stimulation of the have not been evaluated. In spite of the , an alteration in the ampli- small number of patients studied, the large tude of the QRS complex was observed re- number of subcortical areas stimulated in peatedly. Unfortunately, the electrical arti- these individuals and the virtual absence of fact produced by subcortical stimulation was any significant electrocardiographic changes a concomitant occurrence and thus makes allow the valid conclusion that thalamic this finding questionable. and pallidal stimulation and coagulation is a Minimal slowing of cardiac rate (90 to 76 procedure that is not likely to result in sig- beats per rain.) and a single premature ven- nificant cardiac arrhythmias. tricular contraction did result from stimula- tion in the area between the caudate nucleus Summary and deep frontal . 1. In 3 patients serial electrocardiograms were obtained during stimulation of the sub- Discussion cortical areas including the thalamus and That stimulation of specific areas in the globus pallidus. central nervous system will produce hemo- ~. Electrocardiograms were obtained im- dynamic and electrical alterations of the mediately preceding and following destruc- cardiovascular system has been well demon- tive lesions in the region of the nucleus ven- strated. Weinberg and Fuster 5 in animal tralis lateralis of the thalamus. experiments found pronounced electrocardio- 3. No alterations in the electrocardio- graphic changes following stimulation of the grams were observed, including rates, lateral and posterior hypothalamus. These rhythms, intervals or wave form, associated striking changes were predominantly those of with stimulation of the pallidus or stimula- changes in rhythm, both atrial and vcntricu- tion and coagulation in the nucleus ventralis lar. Beattie et al. 1 found hypothalamic stimu- lateralis of the thalamus. lation and destruction to result in cardiac 4. These areas appear to have no effect arrhythmias. upon the electrical activity of the heart as Delgado 2 stated the subiculum, posterior measured by 165 electrocardiographic trac- hypothalamus, and nucleus ings. ventralis lateralis were a group of intracra- nial structures which when stimulated elec- Thanks and appreciation are expressed to Dr. trically would modify cardiac activity. This John M. Van Buren of the Surgical Neurology author did not state or illustrate what these Branch, National Institute of Neurological Di- alterations were. seases and Blindness, National Institutes o[ Health for permitting this study to be carried out The present study failed to show any al- during his surgical treatment of these patients; teration in cardiac rhythm when any of 14 also to Dr. N. Sheldon Skinner of the National different subcortical areas were stimulated Heart Institute for reviewingthis manuscript.