LETTERS TO THE EDITOR
968 "rule of bigeminy" but also deduced the existence of "concealed extrasystoles. " Five years later, Drs. Satou, Kinoshita, and their colleagues2 noted certain patterns of occurrence of such concealed ventricular extrasystoles, and formulated the "rule of multiples." Shortly thereafter, Schamroth and Marriott3 4 also described several examples of regularly occurring concealed extrasystoles. They proposed the terms "concealed bigeminy" and "concealed trigeminy" for those instances in which there were 2n-1 and 3n-1, respectively, conducted sinus beats between extrasystoles (n being any positive integer). A recent paper by Dr. Kinoshita5 and the above letter to the editor by Drs. Kinoshita and Tanabe illustrate how a careful and detailed examination of long rhythm strips containing numerous extrasystoles can yield valuable clues about underlying mechanisms. In their analysis, they assume that the extrasystoles, both manifest and concealed, "ectopic focus." Furthermore, they adduce two principal mechanisms to account for the concealment of some of the extrasystoles; namely, (a) an "exit block" in an ectopic-ventricular (E-V) junction, and (b) "interference," or the arrival of the ectopic impulse at a time when the ventricles are still refractory from the passage of the conducted sinus impulse. However, in his recent paper,5 Dr. Kinoshita concedes that the re-entry hypothesis appears to be preferable to the ectopic enhancement theory as the basis for concealed and manifest extrasystoles. In a recent paper,6 we also attempted to unravel some of the basic mechanisms underlying concealed extrasystoles. We employed the re-entry theory to account for typical concealed bigeminy and some of its variants. The principal components in our hypothesis closely parallel those propounded above by Drs. Kinoshita and Tanabe. In our model, we postulated a 2:1 block at some site in the re-entry loop; this resembles their 2:1 exit block at the E-V junction. Also, we proposed a second, more distal site of block or refractoriness, either in the re-entry loop itself or in the ventricular myocardium (as a consequence of the passage of the conducted sinus impulse). Our more distal site of block in the re-entry loop is analogous to that which Kinoshita and Tanabe depict in figure 1 as that which occurs after the ectopic impulse has invaded "a small portion of the E-V junction." In parallel with our explanation based on the refractoriness of the ventricular cells after excitation, they have aptly applied the term "--interference"-- to the same mechanism. In their letter to the editor, Drs. Kinoshita and Tanabe distinguish between A and B types of concealed bigeminy. These designations correspond to the "odd number" (or classical) and "even number" variants, respectively, which we described recently.6 In that same paper, we also described a variant of concealed bigeminy in which the manifest extrasystoles were interpolated. Drs. Kinoshita and Tanabe have also described such a case in their letter (fig. 1), and assert that their example corresponds to their type B, whereas ours belonged to their type A classification. Their principal evidence was derived from another recording from the same patient (fig. 2 above). At the time of this tracing, the sinus rate was considerably slower than that which prevailed in figure 1. Although Drs. Kinoshita and Tanabe may be correct in their deduction about the distinction between their case and ours, their evidence is tenuous. The underlying mechanism may have changed during the passage of time between recording figures 1 and 2, particularly as a result of the change in sinus rate. For example, in figure 3 from our recent paper,6 a sudden change in heart originate in
rate was accompanied by an instantaneous shift from the "even" (type B) to the "odd" (type A) variant. Analysis of a limited number of long rhythm strips strongly suggests to us that concealed bigeminy and trigeminy and their variants are commonplace. Such long tracings deserve careful analysis, because insight may be gained into the basic mechanism underlying such frequent rhythm disturbances. Dr. Kinoshita and his colleagues deserve considerable credit for their valuable contributions to this important field. MATTHEW N. LEVY, M. D. Mt. Sinai Hospital
Cleveland, Ohio References PICK A, WINTERNITZ M: Mechanisms of intermittent ventricular bigeminy. I. Appearance of ectopic beats dependent upon length of the ventricular cycle, the 'Rule of Bigeminy." Circulation 11: 422, 1955
1. LANGENDORF R,
some
2. SATOU T, KINOSHITA S, TANABE Y, KAWASAKI T, KATOU K, ODA
3. 4. 5.
6.
M, YAMAMOTO K, KAMADA H, YosHIDA T: Impulse conductivity in the region surrounding the extrasystolic focus; Wenckebach phenomenon of the coupling intervals, and the rule of multiples." Saishin-Igaku (Modern Medicine) 15: 1865, 1960 SCHAMROTH L, MARRIOTT HJL: Intermittent ventricular parasystole with observations on its relationship to extrasystolic bigeminy. Am J Cardiol 7: 799, 1961 SCHAMROTH L, MARRIOTT HJL: Concealed ventricular extrasystoles. Circulation 27: 1043, 1963 KINOSHITA S: Concealed ventricular extrasystoles due to interference and due to exit block. Circulation 52: 230, 1975 LEVY MN, ADLER DA, LEVY JR: Three variants of concealed bigeminy. Circulation 51: 646, 1975
Early Discharge after AMI To the Editor: We were interested in the paper by MdNeer et al.' in which they consider that a proportion of patients with acute myocardial infarction could be discharged by the seventh day. We have carried out a trial along these lines.2 Of 275 consecutive patients with myocardial infarction surviving six days 109 (40%) were classified as fit for early discharge and none of these died in the following three months. Seventyfour (68%) of these patients were discharged by the seventh day and 103 (94%) by the ninth day. Adverse factors were persistent sinus tachycardia in the first 48 hours, further cardiac pain or dysrhythmia after 48 hours and persistent STsegment elevation. Patients with these risks were kept in hospital for a longer period. This work continues and we feel that we may well be able to further shorten the hospital stay of these patients. J. M. BARBER, M.D., F.R.C.P.E. D. MCC. BOYLE, M.D., M.R.C.P.
Ulster Hospital Belfast, BT16 ORH, N. Ireland References 1. MCNEER JF, WALLACE AG, WAGNER GS, STARMER CF, ROSATI
RA: Circulation 51: 410, 1975 2. CHATURVEDI NC, WALSH MJ, EVANS A, MUNRO P, BOYLE MCC,
BARBER JM: Br Heart J 36: 533, 1974 Circulation, Volume 52, November 1975
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Letter: Early discharge after AMI. J M Barber and D M Boyce Circulation. 1975;52:968 doi: 10.1161/01.CIR.52.5.968 Circulation is published by the American Heart Association, 7272 Greenville Avenue, Dallas, TX 75231 Copyright © 1975 American Heart Association, Inc. All rights reserved. Print ISSN: 0009-7322. Online ISSN: 1524-4539
The online version of this article, along with updated information and services, is located on the World Wide Web at: http://circ.ahajournals.org/content/52/5/968.citation
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968 "rule of bigeminy" but also deduced the existence of "concealed extrasystoles. " Five years later, Drs. Satou, Kinoshita, and their colleagues2 noted certain patterns of occurrence of such concealed ventricular extrasystoles, and formulated the "rule of multiples." Shortly thereafter, Schamroth and Marriott3 4 also described several examples of regularly occurring concealed extrasystoles. They proposed the terms "concealed bigeminy" and "concealed trigeminy" for those instances in which there were 2n-1 and 3n-1, respectively, conducted sinus beats between extrasystoles (n being any positive integer). A recent paper by Dr. Kinoshita5 and the above letter to the editor by Drs. Kinoshita and Tanabe illustrate how a careful and detailed examination of long rhythm strips containing numerous extrasystoles can yield valuable clues about underlying mechanisms. In their analysis, they assume that the extrasystoles, both manifest and concealed, "ectopic focus." Furthermore, they adduce two principal mechanisms to account for the concealment of some of the extrasystoles; namely, (a) an "exit block" in an ectopic-ventricular (E-V) junction, and (b) "interference," or the arrival of the ectopic impulse at a time when the ventricles are still refractory from the passage of the conducted sinus impulse. However, in his recent paper,5 Dr. Kinoshita concedes that the re-entry hypothesis appears to be preferable to the ectopic enhancement theory as the basis for concealed and manifest extrasystoles. In a recent paper,6 we also attempted to unravel some of the basic mechanisms underlying concealed extrasystoles. We employed the re-entry theory to account for typical concealed bigeminy and some of its variants. The principal components in our hypothesis closely parallel those propounded above by Drs. Kinoshita and Tanabe. In our model, we postulated a 2:1 block at some site in the re-entry loop; this resembles their 2:1 exit block at the E-V junction. Also, we proposed a second, more distal site of block or refractoriness, either in the re-entry loop itself or in the ventricular myocardium (as a consequence of the passage of the conducted sinus impulse). Our more distal site of block in the re-entry loop is analogous to that which Kinoshita and Tanabe depict in figure 1 as that which occurs after the ectopic impulse has invaded "a small portion of the E-V junction." In parallel with our explanation based on the refractoriness of the ventricular cells after excitation, they have aptly applied the term "--interference"-- to the same mechanism. In their letter to the editor, Drs. Kinoshita and Tanabe distinguish between A and B types of concealed bigeminy. These designations correspond to the "odd number" (or classical) and "even number" variants, respectively, which we described recently.6 In that same paper, we also described a variant of concealed bigeminy in which the manifest extrasystoles were interpolated. Drs. Kinoshita and Tanabe have also described such a case in their letter (fig. 1), and assert that their example corresponds to their type B, whereas ours belonged to their type A classification. Their principal evidence was derived from another recording from the same patient (fig. 2 above). At the time of this tracing, the sinus rate was considerably slower than that which prevailed in figure 1. Although Drs. Kinoshita and Tanabe may be correct in their deduction about the distinction between their case and ours, their evidence is tenuous. The underlying mechanism may have changed during the passage of time between recording figures 1 and 2, particularly as a result of the change in sinus rate. For example, in figure 3 from our recent paper,6 a sudden change in heart originate in
rate was accompanied by an instantaneous shift from the "even" (type B) to the "odd" (type A) variant. Analysis of a limited number of long rhythm strips strongly suggests to us that concealed bigeminy and trigeminy and their variants are commonplace. Such long tracings deserve careful analysis, because insight may be gained into the basic mechanism underlying such frequent rhythm disturbances. Dr. Kinoshita and his colleagues deserve considerable credit for their valuable contributions to this important field. MATTHEW N. LEVY, M. D. Mt. Sinai Hospital
Cleveland, Ohio References PICK A, WINTERNITZ M: Mechanisms of intermittent ventricular bigeminy. I. Appearance of ectopic beats dependent upon length of the ventricular cycle, the 'Rule of Bigeminy." Circulation 11: 422, 1955
1. LANGENDORF R,
some
2. SATOU T, KINOSHITA S, TANABE Y, KAWASAKI T, KATOU K, ODA
3. 4. 5.
6.
M, YAMAMOTO K, KAMADA H, YosHIDA T: Impulse conductivity in the region surrounding the extrasystolic focus; Wenckebach phenomenon of the coupling intervals, and the rule of multiples." Saishin-Igaku (Modern Medicine) 15: 1865, 1960 SCHAMROTH L, MARRIOTT HJL: Intermittent ventricular parasystole with observations on its relationship to extrasystolic bigeminy. Am J Cardiol 7: 799, 1961 SCHAMROTH L, MARRIOTT HJL: Concealed ventricular extrasystoles. Circulation 27: 1043, 1963 KINOSHITA S: Concealed ventricular extrasystoles due to interference and due to exit block. Circulation 52: 230, 1975 LEVY MN, ADLER DA, LEVY JR: Three variants of concealed bigeminy. Circulation 51: 646, 1975
Early Discharge after AMI To the Editor: We were interested in the paper by MdNeer et al.' in which they consider that a proportion of patients with acute myocardial infarction could be discharged by the seventh day. We have carried out a trial along these lines.2 Of 275 consecutive patients with myocardial infarction surviving six days 109 (40%) were classified as fit for early discharge and none of these died in the following three months. Seventyfour (68%) of these patients were discharged by the seventh day and 103 (94%) by the ninth day. Adverse factors were persistent sinus tachycardia in the first 48 hours, further cardiac pain or dysrhythmia after 48 hours and persistent STsegment elevation. Patients with these risks were kept in hospital for a longer period. This work continues and we feel that we may well be able to further shorten the hospital stay of these patients. J. M. BARBER, M.D., F.R.C.P.E. D. MCC. BOYLE, M.D., M.R.C.P.
Ulster Hospital Belfast, BT16 ORH, N. Ireland References 1. MCNEER JF, WALLACE AG, WAGNER GS, STARMER CF, ROSATI
RA: Circulation 51: 410, 1975 2. CHATURVEDI NC, WALSH MJ, EVANS A, MUNRO P, BOYLE MCC,
BARBER JM: Br Heart J 36: 533, 1974 Circulation, Volume 52, November 1975
Downloaded from http://circ.ahajournals.org/ by guest on April 8, 2015
Letter: Early discharge after AMI. J M Barber and D M Boyce Circulation. 1975;52:968 doi: 10.1161/01.CIR.52.5.968 Circulation is published by the American Heart Association, 7272 Greenville Avenue, Dallas, TX 75231 Copyright © 1975 American Heart Association, Inc. All rights reserved. Print ISSN: 0009-7322. Online ISSN: 1524-4539
The online version of this article, along with updated information and services, is located on the World Wide Web at: http://circ.ahajournals.org/content/52/5/968.citation
Permissions: Requests for permissions to reproduce figures, tables, or portions of articles originally published in Circulation can be obtained via RightsLink, a service of the Copyright Clearance Center, not the Editorial Office. Once the online version of the published article for which permission is being requested is located, click Request Permissions in the middle column of the Web page under Services. Further information about this process is available in the Permissions and Rights Question and Answer document. Reprints: Information about reprints can be found online at: http://www.lww.com/reprints Subscriptions: Information about subscribing to Circulation is online at: http://circ.ahajournals.org//subscriptions/
Downloaded from http://circ.ahajournals.org/ by guest on April 8, 2015
