Diagnosing benign early repolarization

Correspondence EFFECTIVENESS OF MECHANICALVERSUS MANUAL CHEST COMPRESSIONS IN OUT-OF-HOSPITAL CARDIAC RESUSCITATION To the Editor:--We enjoyed the report of Dickinson et al I and want to add two minor points. First, concerning the (in)effectiveness of manual compressions in out-of-hospital transport, there are two additional mannequin studies from the US that appeared in nonindexed journals. 2,3 Both included the comparison of manual and mechanical cardiopulmonary resuscitation (CPR) and were in favor of the latter. Recently two simulator trials from Europe were published. 4,5 They show that the problem (which is partly dependent on the design of ambulance or helicopter 3,5,6) exists in Europe, also. Second, the relation between expired carbon dioxide, cardiac output, and outcome, which Dickinson et al trace back to 1978, was described almost half a century earlier. Rudolf Eisenmenger, testing a mechanical CPR device (!) named "Biomotor" on dogs, began to measure expired CO2 under CPR in 1929 to check for effective gas exchange. 7 The device used for quantitative CO2 measurement was called "Carboskop," but no technical details were given. 8 In 1939 he wrote: "If during a resuscitation attempt the analysis of the expired air, performed about twice per hour, still shows plenty of carbon dioxide, then continuation of artificial respiration [and circulation] would be indicated. If, however, a sharply declining carbon dioxide elimination in expired air is found, or even more a cessation of [carbon dioxide elimination], then further attempts are futile. ''9 In 1957, Leigh et all0 were the first to use infrared capnography to guide direct cardiac massage in humans. In 1967, Smalhout n described the capnogram during cardiac arrest and resuscitation in great detail. KATHARINAP. KOETTER,MD

Neurological Critical Care Unit Leopoldina Hospital Schweinfurt, Germany WOLFGANGH. MALECK

9. Eisenmenger R: Saug- und Druckluft 0ber dem Bauch, deren Wirkung und Anwendung. Wien Med Wochenschr 1939;89:861-864 10. Leigh MD, Jenkins LC, Belton MK, et al: Continuous alveolar carbon dioxide analysis as a monitor of pulmonary blood flow. Anesthesiology 1957;18:878-882 11. Smalhout B: Capnografie bij de diagnostiek, operatie en nabehandeling van neurochirurgische aandoeningen. Utrecht, University of Utrecht (MD Thesis), 1967

DIAGNOSING BENIGN EARLYREPOLARIZATION To the Editor:---The importance of the electrocardiogram (ECG) in ruling in or out an acute myocardial infarction in a patient presenting with chest pain to the emergency department (ED) is well known. ST segment elevation remains an important diagnostic sign. Unfortunately, numerous other noninfarction syndromes that may occur in patients with chest pain may manifest ST segment elevations. Brady, 1 in a succinct review, pointed out four useful signs as favoring benign early repolarization: upward concavity of the initial portion of the ST segment, notching or slurring of the terminal QRS complex, diffuse ST segment elevations, and concordant T waves of large amplitude. Unfortunately, exceptions to these rules often are encountered by ED physicians almost every day. The most reliable method of diagnosing certain ST segment elevations as benign early repolarization is to prove that they were present on the patient's previous ECGs when he or she did not have any chest pain. For this reason, I always give the patient a copy of his or her ECG to carry, especially if it shows ST segment elevations.2-4Another means of rapid differentiation is by obtaining copies of the patient's prior ECGs for comparison. This can be quickly accomplished by fax. 5 Fax machines are available throughout the world, and transmission of ECGs by fax can be accomplished within a few seconds, whether across town or around the world. As the Chinese saying goes, one picture is better than a thousand words. This is certainly true in the case of comparing ECGs.

Anesthesiology Klinikum Ludwigshafen Ludwigshafen, Germany

TSUNGO. CHENG,MD

Division of Cardiology Department of Medicine George Washington University Medical Center Washington, DC

References 1. Dickinson ET, Verdile VP, Schneider RM, et al: Effectiveness of mechanical versus manual chest compressions in out-of-hospital cardiac arrest resuscitation: A pilot study. Am J Emerg Med 1998;16: 289-292 2. Roberts BG: Machine vs. manual cardiopulmonary resuscitation in moving vehicles. EMT J 1979;3:30-34 3. Stapleton ER: Comparing CPR during ambulance transport. J Emerg Med Serv 1991;16:63-72 4. Sunde K, Wik L, Steen PA: Quality of mechanical, manual standard and active compression-decompression CPR on the arrest site and during transport in a manikin model. Resuscitation 1997;34: 235-242 5. Braunfels S, Meinhard K, Zieher B, et al: A randomized, controlled trial of the efficacy of closed chest compressions in ambulances. Prehosp Emerg Care 1997;1:128-131 6. Thomas SH, Stone CK, Bryan-Berge D: The ability to perform closed chest compressions in helicopters. Am J Emerg Mad 1994;12: 296-298

7. Eisenmenger R: Tierversuche mit dem Apparat zur Erzielung k0nstlicher Atmung, "Biomotor." Wien Kiln Wochenschr 1929;42:15021503 8. Eisenmenger R: Supraabdominale Saug- und DruckluftTherapie mit dem "Biomotor." ML)nchen, Lautenschl&ger, 1934 210

References 1. Brady W J: Benign early repolarization: Electrocardiographic manifestations and differentiation from other ST segment elevation syndromes. Am J Emerg Med 1998;16:592-597 2. Cheng TO: An ECG credit card. Postgrad Med 1992;92(1 ):41 3. Cheng TO: Photocopying ECGs for all patients. J Gen Intern Mad 1991 ;6:97 4. Cheng TO: Comparing ECGs. South Med J 1991 ;84:1507 5. Cheng TO: Fax machines for thrombolysis. Heart 1998;80:210

TREATMENT OF CAPSAICIN (MACE?) DERMATITIS To the Editor:--i wish to congratulate Mr. Herman and Drs. Kindschu and Shallash on their discovery of a rapidly effective and long-lasting therapy for capsaicin-induced contact dermatitis. 1 Such treatment would also be cost-effective and readily available without the need for medical evaluation, making it superior to other suggested therapeutic regimens. 2-7 Nonetheless, the title of their report, "Treatment of Mace Dermatitis with Topical Antacid Suspension," is incorrect, because pepper spray is not Mace. Oleoresin capsicum (OC) sprays containing 5% to 10% OC have