Br J: first published as 10.1136/hrt.34.6.553 on 1 June 1972. Downloaded from British Heart Journal, I972, 34, 553-560.

Changes in the QRS complex after replacement

F. Follathl and W. R. Ginks2 From the Unit of Clinical Cardiology, Department of Medicine, Royal Postgraduate Medical School, London

The electrocardiograms of 50 patients after isolated aortic were examined. Two main types of postoperative QRS changes were found. In I3 patients intraventricular conduction defects developed, predominantly in theform of a left anterior hemiblock as an isolated lesion or combined with other focal blocks. The other prominent finding was the appearance of abnormal Q waves suggesting inferior wall infarction in 8 patients, and anterior wall infarction in one. Intraventricular conduction defects were interpreted as evidence of involvement of the con- ducting system during removal of the abnormal valve, whereas uneven myocardial blood flow during coronary perfusion was thought to be responsiblefor the appearance of abnormal Q waves. The clinical importance of thesefindings is discussed.

Interest in intraventricular conduction defects develop during . Atrioventri- has recently been renewed by Rosenbaum cular block and bundle-branch block are et al. (i969a). They showed the trifascicular well-known complications after closure of character of the conduction system and intro- ventricular septal defects (McGoon, Ongley, http://heart.bmj.com/ duced the term 'hemiblock' to describe con- and Kirklin, I964; Kulbertus, Coyne, and duction disturbances in one ofthe two divisions Hallidie-Smith, I969) and the frequent of the left bundle. Left anterior hemiblock was development of left parietal block after trans- defined by left axis deviation between -30° ventricular aortic valvotomy has also been and -goo, initial QRS forces directed in- reported (Samson and Bruce, I962). Aortic feriorly and to the right, and slight prolonga- valve replacement, when coronary perfusion tion of the QRS duration by o0o2 sec or less and cross-clamping of the present (Rosenbaum et al., I969c). Left posterior additional hazards to the myocardium, seems on September 30, 2021 by guest. Protected copyright. hemiblock was characterized by right axis to carry an increased risk of intraventricular deviation to + I200, superiorly directed initial conduction defects. In recent reports on valve forces, and terminal QRS forces to the right replacement, the occasional production of and inferiorly (Rosenbaum et al., Ig6gb; atrioventricular block has been described Castellanos et al., I969). (Kloster, Bristow and Griswold, I965; Focal conduction defects not only change Gannon et al., I965) but the incidence of the QRS complex profoundly, thus obscur- bundle-branch block or changes of the elec- ing the signs of ventricular hypertrophy and trical axis were not mentioned. , but they may be the In this paper, the electrocardiographic first warning of complete atrioventricular changes were analysed in 50 patients in block which may threaten life. Considering order to investigate postoperative abnormali- the anatomical relation of the bundle of His ties of the QRS complex. and its main branches to the ventricular sep- tum and the aortic valve (Fig. i), mechanical Patients and methods injury to these structures seems likely to Fifty patients undergoing isolated aortic valve Received 7 June 1971. replacement between 1967 and 1970 were in- 1 Present address: Department of Cardiac Surgery, cluded in this study (42 Starr-Edwards valves, Buergerspital, Basle, Switzerland. 7 homografts, and i fascia lata repair). The only 2 Present address: Department of Medicine, Univer- criterion for inclusion in this study was the avail- sity Hospital of San Diego County, 225 West Dickin- ability of a 12 lead pre- and postoperative electro- son Street, San Diego, California 92I03, U.S.A. cardiogram. Patients who died in the immediate 554 Follath and Ginks Br Heart J: first published as 10.1136/hrt.34.6.553 on 1 June 1972. Downloaded from

Results The electrocardiographic changes in the 50 patients after aortic valve replacement are listed in the Table.

(a) Preoperative abnormalities In 7 pa- tients there was evidence of pre-existing intraventricular conduction defect. In one there was complete which re- gressed after operation to right bundle- branch block with left anterior hemiblock. Three patients had complete left bundle- branch block before operation; i developed right bundle-branch block with left anterior hemiblock after operation, another regressed to left anterior hemiblock and in the other patient left bundle-branch block persisted after operation. Three further patients had left anterior hemiblock before operation and this conduction defect persisted after valve replacement. In i patient there were abnormal Q waves in leads II, III, and aVf before operation. This patient developed changes suggesting FIG. I Schematic representation of the anterior wall infarction after operation, the intraventricular conducting system viewed details of which are discussed later. from the left (LV) showing its relation to aortic and mitral valves. A= aorta; AMV= anterior mitral leaflet; (b) Postoperative development of intra- LAB = anterior division of the left bundle; ventricular conduction defects The dif-

LPB =posterior division of the left bundle; ferent types of intraventricular conduction http://heart.bmj.com/ RB = right bundle-branch (coursing the right defect occurring after operation are sche- ventricular septal surface). (Modified after matically represented in Fig. 2. Hudson, I967.) Damage to all three fascicles (trifascicular block) was found in 2 patients. The first developed complete AV block during opera- tion, needing artificial pacing for three days. The electrocardiogram subsequently changed to left bundle-branch block with first degree postoperative period without having a complete on September 30, 2021 by guest. Protected copyright. electrocardiogram recorded were thus excluded from the series. There were no late deaths among the patients. The electrocardiograms were analysed for TABLE QRS changes in 50 patients after changes of the QRS complex with special empha- sis on the following criteria. (I) Initial ventricular aortic valvEe replacement activation (0o02 sec vector); (2) frontal plane QRS axis; (3) terminal QRS forces; (4) duration (i) Preoperative pre-existing abnormalities (8 patients) of the QRS Serial (a) Conduction defects complex. postoperative electro- Trifascicular block I cardiograms were reviewed to examine the Bifascicular block 3 evolution of the different changes. Left anterior hemiblock 3 The routine procedure at valve replacement (b) Abnormal Q waves in leads II, III, aVF I consisted of (i) initiation of cardiac bypass and cooling tO 32°C; (2) aorta cross-clamped and (2) Postoperative changes (22 patients) opened; (3) perfusion of both (a) Conduction defects to maintain a pressure of 70-90 mmHg (mean); Trifascicular block 2 (4) fibrillation of the heart; (5) excision of the Bifascicular block 2 abnormal valve and valve replacement. Left anterior hemiblock 9 Operative data relating to coronary perfusion (b) Abnormal Q waves and aortic clamping, the state of the aortic valve, In leads II, III, aVF 8 and the site of calcification and its subvalvular In VI-V4 I extension, were analysed. The early postoperative (3) No postoperative change (20 patients) course was also studied in each patient. Br Heart J: first published as 10.1136/hrt.34.6.553 on 1 June 1972. Downloaded from Changes in the QRS complex after aortic valve replacement 555

AV block and later to left anterior hemiblock Seven patients had homograft valve re- (Fig. 3). During follow-up, left bundle- placements and, of these, i developed a branch block returned several times with postoperative conduction defect, i developed tachycardia. The second patient had left postoperative Q waves, and in the remaining bundle-branch block before operation which 5 patients there was no change in the post- changed to right bundle-branch block with operative electrocardiogram. left anterior hemiblock after valve replacement One further patient had a fascia lata valve (Fig. 4). replacement without any change in the Bifascicular block developed in 2 patients. cardiogram. Normal intraventricular conduction changed to right bundle-branch block with left anterior hemiblock in one (Fig. 5) and to left bundle- INTRAVENTRICULAR CONDUCTION DEFECTS AFTER branch block in the other. Left anterior hemiblock was the most fre- AORTIC VALVE REPLACEMENT quent finding. In 6 patients, there was ab- normal left axis deviation with an inferiorly directed initial vector and minimal widening POSTOPERATIVE E. C. G. of the QRS complex (

(2) Coronary perfusion Of the 50 patients, 42 had both right and left coronary arteries perfused during operation. Thirteen of these patients developed postoperative conduction defects, i.e. all patients with conduction de- fects had both coronaries perfused. A further 5 developed postoperative Q waves, including 2 patients in whom blood flow in the right coronary artery was inadequate and had to A. 19/1067 be interrupted several times during operation and i patient in whom anomalies of the right and left circumflex coronary arteries were shown by preoperative coronary angiography. The remaining 24 patients showed no change

in the postoperative cardiogram. .~~~~~~~~~~~~~'' In the remaining patient, the aorta was clamped at 29gC for 45 minutes without any form of coronary perfusion but this patient showed no postoperative electro- V1 cardiographic changes. V4~~~~~~~1 B. 2411067 (3) Calcification of aortic valve Heavy calci- fication of the aortic valve with subvalvar extension of calcium was described by the surgeon in 9 patients; 2 already had pre- existing preoperative conduction defects, 4 .A developed postoperative conduction defects, C. 3/11/67 I developed postoperative Q waves, and in the remaining 2 patients there was no change in the electrocardiogram after operation. 4+t

11 11 aVi aV'..a. aVF http://heart.bmj.com/ Discussion The incidence of postoperative electrocardio- graphic changes was high after aortic valve replacement. The abnormalities observed suggest damage to the conducting system and myocardium since the QRS complex, in contrast to the phase of repolarization, is not B. 7 21167 2 V3 usually influenced by digitalis, antiarrhyth- mic agents, electrolyte changes, and peri- on September 30, 2021 by guest. Protected copyright. cardotomy. Of the patients with intraventricular con- X<1+ il a duction defects, involvement of the anterior ~~il- a-VR- a- division of the left bundle was present in all, |= a M:X....zA_:s '@ g feature that is not ;~~~~~~~~~~~~~4 surprising when the close iS~~7 relation of this structure to the aortic valve is considered (Lev, I964). The shift of the 1~~~~~~~Vtt[-r-:- -i & 4:. mean QRS axis and the change in initial V3 ventricular activation in 3 patients were interpreted as indicating partial interruption of the left anterior fibres, that is, incomplete left anterior hemiblock. The existence of FIG. 3 'Trifascicular' block. Normal preoperative intraventricular incomplete left anterior hemiblock, however, conduction (A) changing to complete AV block immediately after opera- is still uncertain (Rosenbaum et al., I969c). tion (B) and later to left bundle-branch block (C) and left anterior Right bundle-branch block was found in 4 hemiblock (D). patients, and a transient conduction defect in the left posterior bundle, never occurring as an isolated lesion, was also noted in 4 pa- tients. The pathogenesis of the conduction defects Br Heart J: first published as 10.1136/hrt.34.6.553 on 1 June 1972. Downloaded from Changes in the QRS complex after aortic valve replacement 557

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FIG . 4 ' Trifascicular' involvement of the conduction system. Preoperative left bundle-branch block (A) changing to right bundle-branch block and left anterior hemiblock after valve replace- http://heart.bmj.com/ ment (B). is probably due to involvement of the con- Left posterior hemiblock has also been shown ducting system during removal of the ab- clinically to cause a shift of the initial QRS normal valve. Haemorrhagic lesions and vector superiorly and therefore Q waves in necrosis of the atrioventricular conducting leads II, III, and aVF (Rosenbaum et al., system have been observed not infrequently I969b). Recently the spontaneous develop- on September 30, 2021 by guest. Protected copyright. after aortic valve replacement (Hudson, I967; ment of wide slurred Q waves in the inferior Niles and Sandilands, I969). Whether con- leads was described in patients with aortic duction defects are more likely to develop valve disease without any evidence of coro- after Starr-Edwards valve insertion than after nary artery disease (Warembourg et al., homograft valve replacement is uncertain, I970). These authors suggested that the re- since the two procedures are not equally gurgitant jet of aortic incompetence was represented in this series. responsible for the abnormal Q waves by The second prominent finding was the causing endocardial fibrosis in the area of development of abnormal Q waves suggesting the left posterior bundle. One of the accepted inferior infarction in 8 patients, and anterior criteria of left posterior hemiblock is, how- wall infarction in i patient. Attention has ever, a rightward shift of the mean frontal been drawn to the association between these plane QRS axis, which is not a feature in our changes and the difficulties of coronary patients with inferior Q waves. artery perfusion. An alternative explanation, In conclusion, the frequency of intraventri- however, which might account for the ap- cular conduction defects after aortic valve pearance of Q waves in the inferior leads is a replacement emphasizes the important ana- conduction disturbance in the left posterior tomical relation between the conducting bundle. Experimental dissection of the left system and the aortic valve cusps. In addi- posterior bundle in primates produces an tion, the development and variability in the electrocardiographic pattern resembling in- types of intraventricular blocks lend further ferior wall infarction (Watt and Pruitt, I969). support to the concept of trifascicular intra- 558 Follath and Ginks Br Heart J: first published as 10.1136/hrt.34.6.553 on 1 June 1972. Downloaded from

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.zt:tt: 0- XXl0 ii _ C- 0 CN > Br Heart J: first published as 10.1136/hrt.34.6.553 on 1 June 1972. Downloaded from 560 Follath and Ginks ventricular conduction. The clinical impor- tance of these conduction defects is not clear. With the exception of the patient with tran- W. H. sient third degree AV block, no haemo- dynamic complications were seen and the 2412170 postoperative course was no different from those without electrocardiographic changes. Nevertheless, it is possible that there is an increased risk of developing complete AV block in later life (Lasser, Haft, and Fried- berg, I968). A ~~~~~~~~~~~~~~1aV111 aVWaV At present, the differentiation between _~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~.H inferior wall infarction and left posterior hemiblock awaits further study. In view of the difficulties of coronary artery perfusion in our patients, myocardial necrosis seems the most likely explanation for the appear- ance of Q waves in the inferior leads. V,1 2 V3 V4 V5 .

We are indebted to Professor J. F. Goodwin for 2D40.1 helpful criticism and advice, and to Mr. W. P. ..uk -^ . -- -.... .X. . .6... Cleland and Professor H. H. Bentall who per- a - ~~~~~~~~~~~ formed the operations. _* =1 111 aVRt

References ...... e aVI aWF Castellanos, A., Jr., Maytin, O., Arcebal, A. G., and .1. Lemberg, L. (I969). Alternating and co-existing block in the divisions of the left bundle branch. Wt Diseases of the Chest, 56, I03. mYF m z_','-F-F -- Gannon, P. G., Sellers, R. D., Kanjuh, V. I., Edwards, ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~.. J. E., and Lillehei, C. W. (I965). Complete heart

block following replacement of the aortic valve. 'Ii~~~~~~~~~~~~~~~~~~~~~~~~~~~EE http://heart.bmj.com/ Circulation, 33-34, Suppl. I, I52. Hudson, R. E. B. (I967). Surgical pathology of the V1 V2 V3 V4 V5 conducting system of the heart. British Heart Journal, 29, 646. Kloster, F. E., Bristow, J. D., and Griswold, H. E. (I965). Medical problems in mitral and multiple FIG. 9 Postoperative anterior wall infarction with poor R wave pro. valve replacement. Progress in Cardiovascular gression in Vi-V3. Diseases, 7, 504. Kulbertus, H. E., Coyne, J. J., and Hallidie-Smith,

K. A. (I969). Conduction disturbances before and on September 30, 2021 by guest. Protected copyright. after surgical closure of ventricular septal defect. American Heart Journal, 77, I23. Lasser, R. P., Haft, J. I., and Friedberg, C. K. (I968). Relationship of right bundle-branch block and marked left axis deviation (with left parietal or Rosenbaum, M. B., Elizari, M. V., Levi, R. J., Nau, peri-infarction block) to complete heart block and G. J., Pisani, N., Lazzari, J. 0., and Halpern, M. S. . Circulation, 37, 429. (1969c). Five cases of intermittent left anterior Lev, M. (I964). Anatomic basis for atrioventricular hemiblock. American J7ournal of Cardiology, 24, I.- block. American Journal of Medicine, 37, 742. Samson, W. E., and Bruce, R. A. (1962). Left ventri- McGoon, D. C., Ongley, P. A., and Kirklin, J. W. cular parietal block produced by transventricular (I964). Surgical heart block. American Journal of aortic commissurotomy. American Heart Journal, Medicine, 37, 749. 63, 41. Niles, N. R., and Sandilands, J. R. (I969). Pathology Warembourg, H., Pauchant, M., Thery, Cl., Lekieffre, of replacement surgery. Diseases of the J., Ducloux, G., and Gosselin, B. (I970). Bloc Chest, 56, 373. intraventriculaire posterieur au cours de l'insuffi- Rosenbaum, M. B., Elizari, M. V., Lazzari, J. O., sance aortique. Archives des Maladies du Cawu et Nau, G. J., Levi, R. J., and Halpern, M. S. des Vaisseaux, 63, 408. (I969a). Intraventricular trifascicular blocks. Wart, T. B., and Pruirt, R. D. (I969). Left posterior Review of the literature and classification. Ameri- fascicular block in canine and primate . can Heart journal, 78, 450. Circulation, 40, 677. Rosenbaum, M. B., Elizari, M. V., Lazzari, J. O., Nau, G. J., Levi, R. J., and Halpern, M. S. (I969b). Intraventricular trifascicular blocks. The Requests for reprints to Dr. W. R. Ginks, syndrome of right bundle-branch block with Departrent of Medicine, University Hospital of intermittent left anterior and posterior hemiblock. San Diego County, 225 West Dickinson Street, American Heart Journal, 78, 306. San Diego, California 92I3, U.S.A.