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Transthoracic pacing in cardiac asystole
Transthoracic Pacing in Cardiac Asystole
Introduction
J. Douglas White, MD A total of 139 patients had transthoracic pacemakers introduced viaa subxiphoidapproach forasystole duringadvanced CPR in the emergency department of a large urban teaching hospital over a calendar year. Two groups were examined retrospectively, A) 34 patients who presented asystolic, and B) 99 patients who presented with ventricular fibrillation that became asystole. Age, sex, and etiologies for cardiac arrest were similar in both groups; there were no survivors. The mean duration of asystole before pacemaker insertion was 4 min (group A) to 7 min (group B). Temporary electrical capture was obtained in six patients fromgroup B, but electrical-mechanical association could not be achieved in any of these patients.
Temporary cardiac pacemakers have been used for many years for various dysrhythmias. Their value in the treatment of tachy and bradyarrhythmias or high-degree atrioventricular block is established and noncontroversial. However, these situations account for only a minority of pacer insertions in many emergency departments and critical care units. Studies have shown that 25% to 31% of cardiac arrests brought to the emergency department are brady-asystolic in nature, l-3 and at our institution, a large urban teaching hospital, over 90% of external pacers are inserted for asystolic arrests. Treating cardiac asystole can be a discouraging exercise. Resuscitation is rare despite advanced methods including external ventilation, cardiac compression, and exhaustive pharmacologic intervention.4 However, while there is a tendency to regard asystolic cardiac arrest as an inevitably terminal event, historical perspective may be gained by recalling similar pessimism with respect to other cardiac conditions in the past. With the patient in extremis, the physician often attempts to externally pace the heart. Reviews of small series have suggested that this may be a futile procedure. There is no clinical consensuson this issue, 115J6but there is evidence that transthoracic pacing can benefit patients with acute myocardial infarction who develop asystole in the hospital.788 The study presented here is a comprehensive review of a large series of patients treated with emergency transthoracic pacing in an effort to assess the efficacy of this procedure.
Materials and Methods
From the Emergency Ward and the Department sachusettsGenera1 Hospital, Boston, Massachusetts.
of Medicine,
Mas-
Address reprint requests to J. Douglas White, MD, Clinical Director, Division of Emergency Medicine, Georgetown University Hospital, 3800 Reservoir Road, NW, Washington, DC 20007. Manuscript submitted 11 January 1983; revisionaccepted4March 1983. Key Words: Asystole; cardiac arrest; cardiac pacing; pacemaker, transthoracic.
264
The charts of all 159 patients who presented with or developed asystole in the Emergency Department of the Massachusetts General Hospital during twelve consecutive months were reviewed. Of these, 139 patients had transthoracic pacers inserted, six of whom were eliminated from the study because of pacer malfunction during the arrest. The transthoracic approach for pacer placement was employed in all cases because of ease, rapidity, and certainty of placement. Elecath”’ transthoracic pacing kits with a curved bipolar pacing stylet and a 6-inch, 1&gauge placement cannula were used in conjunction with a Medtronic@“externaldemandpacemaker. lElectrocather
Corporation, Rahway, NJ, 07065. Model 1 l-KTM. “MedtronicCorporation,Minneapolis,MN,55418. Model @588OA.
American /ournalofEmergencyMedicine
1983,3:264-266
ORICINALCONTRIBUTIONS
Insertion was accomplished by postgraduate year II and III medical housestaff via a subxiphoid approach. Satisfactory placement and electrical functioning were routinely verified in all patients by ease of blood aspiration through the intracardiac needle and the appearance of pacemaker spikes on the electrocardiogram. While postmortem roentgenograms were not performed, autopsies obtained on six patients revealed satisfactory pacer placement in the right ventricle of three patients and right atrium of three patients.
Results Twenty elderly and institutionalized patients who arrived at the Emergency Department in asystole were not paced (group C). These 20 patients not selected for pacing (group Cl were older, referred to the hospital from nursing homes (100% of groupC versus 23% of group A and 12% of group B), and all presented in asystole. The remaining 139 patients were all paced. Of these, 34 patients presented in asystole (group A) and 99 patients presented in ventricular fibrillation that degenerated into asystole within 2 to 64 minutes with a mean of 11.2 minutes (group B). Mechanical pacemaker malfunction was experienced with six patients. Table
TRANSTHORACIC
PACING
Table 2. Etiology of cardiac arrest. Paced Patients GroupA (asystolic on arrival) ASHD by history “Sudden Death” Ino ASHD history) Overdose G.I. Bleed Drowning Pulmonary OEmbdus BluntTrauma Total
Unpaccd Patients
Group B (v. fib.asystole)
Group C (asysmlic on arrival)
23 (68%)
61 162’~)
12 (60%)
X (24%) 2 ml
26 (2606)
6 (30%)
4 (4%) 3 (3%) 2 (2’d 1 (lobI
1b?d 0 iow 0 iow
0 (04,) 0 IO’X,) 1 l2oGl 0 (0961 34(1oo%l
2 12061 99 llOO’~l
1 i5W
0 10'16) 20 llOOS1
were from group B, but mechanical systole could not be achieved in any case and there were no survivors from any group. Table 3. Duration of asystolc before pacemaker Grouo A’ (asystolic (;n arrival1 Mean
3.74 minutes
Range
1 to
I I minutes
insertion.
Grouo B” Iv. fib.asystolcl 6.84 minutes 1 to 2 1 minutes
‘Duration of asystolc outside of hospital unknown. “Patients received CPR for mean time of 11.2 minutes [range 2 to 64 minutcs) while in ventricular fibrillation before the Onset of asystolc.
1,Patients with asystole in the emergency department. Unpaced Patients
Paced Patients
Total No. Mean age Age range Male Female
. WHITE.
Group A (asystolic on arrival)
Group B iv. fib.asystolcl
GroupC (asystolic on arrival)
34 62 21-81 25 (74’Xd
99 64 22-84 76 l76’~l 23 (24%)
20 78 72-90 13 1659bj 7 (35Rll
9 (26’Wll
In groups A and B the average age was approximately 63 years with males outnumbering females by a ratio of 3 to 1 [Table 1). The etiologies for cardiac arrest were similar in all groups with arteriosclerotic heart disease (ASHD) and “sudden cardiac death” present in over 90% of the cases. Nine patients under 40 years of age had the following histories: drug overdose (five patients); sudden cardiac death (two patients]; blunt trauma lone patient); and GI bleed (one patient). The diagnoses of pulmonary embolism were made on autopsy (Table 21. The mean duration of asystole in the Emergency Department before pacer insertion was 3.7 minutes for group A and 6.8 minutes for group B (Table 3). Temporary electrical capture was evinced in six patients, all of whom
Discussion This study delineates the dismal prognosis for cardiac arrest patients who develop asystole. Moreover, early introduction of a functioning external cardiac pacemaker does not alter this result. Presumably, myocardial disease and damage are so profound as to render the conduction and muscular components of the heart refractory toefforts at external pacing. Nevertheless, there is evidence that immediate transthoracic pacing could be of value. Zol19 and Roe and Katz” were among the first to report that external cardiac pacing could restore a viable rhythm in patients with advanced ASHD who develop asystole. Edhag et al’ published a series of 20 patients monitored in the critical care unit for acute myocardial infarction who received transthoracic pacemakers immediately following the supervention of acute asystole. One patient survived and was discharged while the remainder died inelectrical-mechanical dissociation. Autopsy studies revealed extensive myocardial infarction in all cases. Baksi et aZs reported four similar cases in which immediate transthoracic pacing was employed to treat asystole. One patient survived to be dis-
265
AMERlCAN/OURNALOFEMERGENCYMEDIClNE
. VOL 1 . NOVEMBER 1983
charged while the other three died in electricalmechanical dissociation. These authors echoed Edhag’s admonition that transthoracic pacing should be initiated immediately in this setting even before chest compression or the administration of any drugs. Although their combined survival rate was less than lo%, aggressive utilizationof temporary pacing had apparently saved two lives. The patient with asystole in the emergency department can also be presumed to have suffered extensive myocardial damage either from a primary ischemic event or secondary tissue anoxia from diminished perfusion. Efforts to pace the heart under these circumstances were unsuccessful inour series. Transvenous pacing has already been demonstrated to be futile in this situation, ’ l doubtlessly the result of severe cardiac damage and the technical problem of placement in the absence of forward blood flow. Immediate transthoracic pacing of asystolic patients in the emergency department remains to be prospectively evaluated. The resuscitation of a small subset of patients might well be an attainable and desirable goal in light of recent and anticipated advances in myocardial salvage, mechanical augmentation, revascularization, and transplantation. We are currently engaged in a randomized and controlled study of immediate transthoracic cardiac pacing for asystole to address this question.
Conclusion Transthoracic pacing provides no benefit during advanced cardiac life support when delayed more than a few minutes following the onset of asystole. Future studies should be directed toward immediate pacing with the advent of asystole.
References Iseri LT, Humphrey SB, Siner El. Prehuspital InternMed 1978;88:74;-754.
brady-asystolic
arrest. Ann
Liberthson RR, Nagel EL, Hirschman IC et al. Pathophysiologic tionsinprehospital ventricular fibrillationandsuddencardiacdeath. culation 1974;49:790-798. Myerburg RI. Clinical, electrophysmlogic patients resuscitated from prehospital 1980;68:568-576.
and hemodynamic profile of cardiac arrest. Am 1 Med
Brown DC, Lewis AJ. The possible role of parasympathetic temincardiacarrest. lACEP 1979,8:448-45X
266
observaCir-
nervous sys-
Tintinalli I, White BC. Transthoracic pacing during cardiopulmonary resuscitatwn. AnnEmergMed 19R1;10:113-I 16. Roberts \R, Greenberg MI. Emergency EmergMed 1981,10:600-612.
transthoracic
EdhagO, NyqulstO,OrmiusEetal. Cardlacpacing electrode ,n acute myocardlal infarction. 1972,192:145-147.
pacemaker.
Ann
throughtransthoracrc Acta Med Stand
BaksiKB,HossarnA,ChapraDSetal. Transthorac~cpacingmventrudar asystole. IlndianMedAssoc 1973;60: 134-137. 9.
Zoll PM. Resuscltatwn of the heart m ventricular standstdl electricalstimulatwn. NEngllMed 1952;247:768-771
by external
IO.
Roe RB, Katz HJ Complete recurrentventricularfibrillation.
II.
Hazard PB, Benton C, Milnor IP. Transvenous cardiac pacmg m cardiopulmonaryresuscitatlon. CrltCare Med 1981;9;666-668.
heart block wth mtractable asystole and AmICardml 1965; 15:401-403.
Introduction
J. Douglas White, MD A total of 139 patients had transthoracic pacemakers introduced viaa subxiphoidapproach forasystole duringadvanced CPR in the emergency department of a large urban teaching hospital over a calendar year. Two groups were examined retrospectively, A) 34 patients who presented asystolic, and B) 99 patients who presented with ventricular fibrillation that became asystole. Age, sex, and etiologies for cardiac arrest were similar in both groups; there were no survivors. The mean duration of asystole before pacemaker insertion was 4 min (group A) to 7 min (group B). Temporary electrical capture was obtained in six patients fromgroup B, but electrical-mechanical association could not be achieved in any of these patients.
Temporary cardiac pacemakers have been used for many years for various dysrhythmias. Their value in the treatment of tachy and bradyarrhythmias or high-degree atrioventricular block is established and noncontroversial. However, these situations account for only a minority of pacer insertions in many emergency departments and critical care units. Studies have shown that 25% to 31% of cardiac arrests brought to the emergency department are brady-asystolic in nature, l-3 and at our institution, a large urban teaching hospital, over 90% of external pacers are inserted for asystolic arrests. Treating cardiac asystole can be a discouraging exercise. Resuscitation is rare despite advanced methods including external ventilation, cardiac compression, and exhaustive pharmacologic intervention.4 However, while there is a tendency to regard asystolic cardiac arrest as an inevitably terminal event, historical perspective may be gained by recalling similar pessimism with respect to other cardiac conditions in the past. With the patient in extremis, the physician often attempts to externally pace the heart. Reviews of small series have suggested that this may be a futile procedure. There is no clinical consensuson this issue, 115J6but there is evidence that transthoracic pacing can benefit patients with acute myocardial infarction who develop asystole in the hospital.788 The study presented here is a comprehensive review of a large series of patients treated with emergency transthoracic pacing in an effort to assess the efficacy of this procedure.
Materials and Methods
From the Emergency Ward and the Department sachusettsGenera1 Hospital, Boston, Massachusetts.
of Medicine,
Mas-
Address reprint requests to J. Douglas White, MD, Clinical Director, Division of Emergency Medicine, Georgetown University Hospital, 3800 Reservoir Road, NW, Washington, DC 20007. Manuscript submitted 11 January 1983; revisionaccepted4March 1983. Key Words: Asystole; cardiac arrest; cardiac pacing; pacemaker, transthoracic.
264
The charts of all 159 patients who presented with or developed asystole in the Emergency Department of the Massachusetts General Hospital during twelve consecutive months were reviewed. Of these, 139 patients had transthoracic pacers inserted, six of whom were eliminated from the study because of pacer malfunction during the arrest. The transthoracic approach for pacer placement was employed in all cases because of ease, rapidity, and certainty of placement. Elecath”’ transthoracic pacing kits with a curved bipolar pacing stylet and a 6-inch, 1&gauge placement cannula were used in conjunction with a Medtronic@“externaldemandpacemaker. lElectrocather
Corporation, Rahway, NJ, 07065. Model 1 l-KTM. “MedtronicCorporation,Minneapolis,MN,55418. Model @588OA.
American /ournalofEmergencyMedicine
1983,3:264-266
ORICINALCONTRIBUTIONS
Insertion was accomplished by postgraduate year II and III medical housestaff via a subxiphoid approach. Satisfactory placement and electrical functioning were routinely verified in all patients by ease of blood aspiration through the intracardiac needle and the appearance of pacemaker spikes on the electrocardiogram. While postmortem roentgenograms were not performed, autopsies obtained on six patients revealed satisfactory pacer placement in the right ventricle of three patients and right atrium of three patients.
Results Twenty elderly and institutionalized patients who arrived at the Emergency Department in asystole were not paced (group C). These 20 patients not selected for pacing (group Cl were older, referred to the hospital from nursing homes (100% of groupC versus 23% of group A and 12% of group B), and all presented in asystole. The remaining 139 patients were all paced. Of these, 34 patients presented in asystole (group A) and 99 patients presented in ventricular fibrillation that degenerated into asystole within 2 to 64 minutes with a mean of 11.2 minutes (group B). Mechanical pacemaker malfunction was experienced with six patients. Table
TRANSTHORACIC
PACING
Table 2. Etiology of cardiac arrest. Paced Patients GroupA (asystolic on arrival) ASHD by history “Sudden Death” Ino ASHD history) Overdose G.I. Bleed Drowning Pulmonary OEmbdus BluntTrauma Total
Unpaccd Patients
Group B (v. fib.asystole)
Group C (asysmlic on arrival)
23 (68%)
61 162’~)
12 (60%)
X (24%) 2 ml
26 (2606)
6 (30%)
4 (4%) 3 (3%) 2 (2’d 1 (lobI
1b?d 0 iow 0 iow
0 (04,) 0 IO’X,) 1 l2oGl 0 (0961 34(1oo%l
2 12061 99 llOO’~l
1 i5W
0 10'16) 20 llOOS1
were from group B, but mechanical systole could not be achieved in any case and there were no survivors from any group. Table 3. Duration of asystolc before pacemaker Grouo A’ (asystolic (;n arrival1 Mean
3.74 minutes
Range
1 to
I I minutes
insertion.
Grouo B” Iv. fib.asystolcl 6.84 minutes 1 to 2 1 minutes
‘Duration of asystolc outside of hospital unknown. “Patients received CPR for mean time of 11.2 minutes [range 2 to 64 minutcs) while in ventricular fibrillation before the Onset of asystolc.
1,Patients with asystole in the emergency department. Unpaced Patients
Paced Patients
Total No. Mean age Age range Male Female
. WHITE.
Group A (asystolic on arrival)
Group B iv. fib.asystolcl
GroupC (asystolic on arrival)
34 62 21-81 25 (74’Xd
99 64 22-84 76 l76’~l 23 (24%)
20 78 72-90 13 1659bj 7 (35Rll
9 (26’Wll
In groups A and B the average age was approximately 63 years with males outnumbering females by a ratio of 3 to 1 [Table 1). The etiologies for cardiac arrest were similar in all groups with arteriosclerotic heart disease (ASHD) and “sudden cardiac death” present in over 90% of the cases. Nine patients under 40 years of age had the following histories: drug overdose (five patients); sudden cardiac death (two patients]; blunt trauma lone patient); and GI bleed (one patient). The diagnoses of pulmonary embolism were made on autopsy (Table 21. The mean duration of asystole in the Emergency Department before pacer insertion was 3.7 minutes for group A and 6.8 minutes for group B (Table 3). Temporary electrical capture was evinced in six patients, all of whom
Discussion This study delineates the dismal prognosis for cardiac arrest patients who develop asystole. Moreover, early introduction of a functioning external cardiac pacemaker does not alter this result. Presumably, myocardial disease and damage are so profound as to render the conduction and muscular components of the heart refractory toefforts at external pacing. Nevertheless, there is evidence that immediate transthoracic pacing could be of value. Zol19 and Roe and Katz” were among the first to report that external cardiac pacing could restore a viable rhythm in patients with advanced ASHD who develop asystole. Edhag et al’ published a series of 20 patients monitored in the critical care unit for acute myocardial infarction who received transthoracic pacemakers immediately following the supervention of acute asystole. One patient survived and was discharged while the remainder died inelectrical-mechanical dissociation. Autopsy studies revealed extensive myocardial infarction in all cases. Baksi et aZs reported four similar cases in which immediate transthoracic pacing was employed to treat asystole. One patient survived to be dis-
265
AMERlCAN/OURNALOFEMERGENCYMEDIClNE
. VOL 1 . NOVEMBER 1983
charged while the other three died in electricalmechanical dissociation. These authors echoed Edhag’s admonition that transthoracic pacing should be initiated immediately in this setting even before chest compression or the administration of any drugs. Although their combined survival rate was less than lo%, aggressive utilizationof temporary pacing had apparently saved two lives. The patient with asystole in the emergency department can also be presumed to have suffered extensive myocardial damage either from a primary ischemic event or secondary tissue anoxia from diminished perfusion. Efforts to pace the heart under these circumstances were unsuccessful inour series. Transvenous pacing has already been demonstrated to be futile in this situation, ’ l doubtlessly the result of severe cardiac damage and the technical problem of placement in the absence of forward blood flow. Immediate transthoracic pacing of asystolic patients in the emergency department remains to be prospectively evaluated. The resuscitation of a small subset of patients might well be an attainable and desirable goal in light of recent and anticipated advances in myocardial salvage, mechanical augmentation, revascularization, and transplantation. We are currently engaged in a randomized and controlled study of immediate transthoracic cardiac pacing for asystole to address this question.
Conclusion Transthoracic pacing provides no benefit during advanced cardiac life support when delayed more than a few minutes following the onset of asystole. Future studies should be directed toward immediate pacing with the advent of asystole.
References Iseri LT, Humphrey SB, Siner El. Prehuspital InternMed 1978;88:74;-754.
brady-asystolic
arrest. Ann
Liberthson RR, Nagel EL, Hirschman IC et al. Pathophysiologic tionsinprehospital ventricular fibrillationandsuddencardiacdeath. culation 1974;49:790-798. Myerburg RI. Clinical, electrophysmlogic patients resuscitated from prehospital 1980;68:568-576.
and hemodynamic profile of cardiac arrest. Am 1 Med
Brown DC, Lewis AJ. The possible role of parasympathetic temincardiacarrest. lACEP 1979,8:448-45X
266
observaCir-
nervous sys-
Tintinalli I, White BC. Transthoracic pacing during cardiopulmonary resuscitatwn. AnnEmergMed 19R1;10:113-I 16. Roberts \R, Greenberg MI. Emergency EmergMed 1981,10:600-612.
transthoracic
EdhagO, NyqulstO,OrmiusEetal. Cardlacpacing electrode ,n acute myocardlal infarction. 1972,192:145-147.
pacemaker.
Ann
throughtransthoracrc Acta Med Stand
BaksiKB,HossarnA,ChapraDSetal. Transthorac~cpacingmventrudar asystole. IlndianMedAssoc 1973;60: 134-137. 9.
Zoll PM. Resuscltatwn of the heart m ventricular standstdl electricalstimulatwn. NEngllMed 1952;247:768-771
by external
IO.
Roe RB, Katz HJ Complete recurrentventricularfibrillation.
II.
Hazard PB, Benton C, Milnor IP. Transvenous cardiac pacmg m cardiopulmonaryresuscitatlon. CrltCare Med 1981;9;666-668.
heart block wth mtractable asystole and AmICardml 1965; 15:401-403.