Catheterization and Cardiovascular Diagnosis 27:45-48 (1992)
ST Segment Alternans During Coronary Angioplasty Mirek Sochanski, MD, Ted Feldman, MD, FSCAI, K.G. Chua, MD, Andrew Benn, MD, and Rory Childers, MUD Four patients with severe proximal or mid-LAD stenosis were noted to have ST alternans during balloon angioplasty. Neither mechanical alternans nor increased ventricular ectopy were noted. In contrast to prior descriptions in animals or patients with variant angina, ST alternans did not occur following a premature ventricular contraction. Frequent use of calcium channel blockers during PTCA may interfere with the mechanism leading to electrical alternans and its consequences as seen in animal studies, accounting for the low frequency with which this phenomenon is noted during PTCA. 0 1992 Wiley-Liss,
Inc.
Key words: electrocardiogram, PTCA, myocardial ischemia
INTRODUCTION
Electrical alternans of the ST segment have been well characterized following experimental coronary occlusion in animals [l-31 and, clinically, in patients with variant angina [4]or a prolonged QT interval [5]. It has been demonstrated that ST alternans may be associated with ventricular arrhythmias [I]. This report described ST segment alternans that occurred in 4 patients during percutaneous transluminal coronary angioplasty (PTCA) . A 39-year-old male with stable exertional angina, prior inferior myocardial infarction, and a positive stress test was referred for cardiac catheterization. Resting ECG showed Q waves in the inferior leads, nonspecific ST-T segment changes, and a normal QT interval. Coronary angiography demonstrated a totally occluded proximal right coronary artery (RCA), eccentric 90 percent mid-left anterior descending artery (LAD) stenosis, and 80% mid-obtuse marginal stenosis. Good collateral flow from the LAD to the distal RCA was present. Left ventricular angiography showed preserved overall left ventricular function with severe hypokinesis of the inferior and inferobasal walls. Medications included atenolol, isosorbide dinitrate, allopurinol, acetaminophen with codeine, and triazolam. PTCA of the LAD and obtuse marginal was planned. The LAD lesion was crossed without difficulty, and 1 inflation of 5 atmospheres for 100 seconds was performed. Eighty-six seconds into the balloon inflation, ST segment alternans appeared. This persisted for 1 minute and 55 seconds after balloon deflation. The most pronounced ECG changes were observed in lead I (Fig. 1). During ST alternans, no changes in blood pressure or heart rate were noted. The patient experienced mild substernal chest pain typical for his anginal pain that re0 1992 Wiley-Liss, Inc.
solved soon after balloon deflation. Next, successful PTCA of the obtuse marginal artery was performed but no ST alternans occurred, although the patient had ST segment depression and similar substernal chest pain. Subsequently, a 12-lead ECG remained unchanged and a signal-averaged ECG was normal. A 44-year-old female returned with unstable angina 2 months after uncomplicated PTCA of a proximal LAD stenosis. She was treated with intravenous nitroglycerine, heparin, nifedipine, and enteric aspirin. Repeat angiography showed recurrence of the proximal LAD stenosis assessed to be 90%. PTCA of the LAD was undertaken. During the first inflation, after 90 seconds the patient developed ST segment alternans, best seen in lead I, and left bundle branch block with left axis deviation (Fig. 2). This was followed by her usual anginal pain, which resolved shortly after balloon deflation. Two other inflations that were performed subsequently for a shorter duration did not cause ST alternans. A 65-year-old woman with no previous cardiac history was admitted with unstable angina. She was treated with heparin and intravenous nitroglycerine. Cardiac catheterization showed a 95% eccentric mid-LAD lesion, followed by 85% distal LAD stenosis, 80% proximal ramus intermedius lesion, and 70-80% stenosis of the proximal
From the University of Chicago Hospitals, Department of Medicine, Section of Cardiology, Hans Hecht Hernodynamics Laboratory, Chicago, Illinois.
Received January 15, 1992; revision accepted April 7, 1992. Address reprint requests to Ted Feldman, M.D., University of Chicago Hospitals, 5841 S. Maryland Avenue, Mail Code-5076. Chicago, IL 60637.
46
-
Sochanski et al.
BALLOON INFLATION
BASELINE
........................................ I II
,,,,,,
, ,
, , , , , ,,-, , , , , , , , , , , , ,/ , , , , , , , , , , , I
I
,
,
,
I
I
,
,
,, ,, ,,,
,
I
,
,
,
, , , ,, , ,
.?,5, .'?m/
Ao
-
Fig. 1. On the left is the baseline electrocardiogram prior to balloon inflation. Frontal ECG leads and the aortic pressure (Ao) recorded from the guiding catheter are displayed. During balloon inflation there is ECG ST alternans with minimal QRS widening, most prominent in lead I (arrows), with no hemodynamic changes and no QRS alternans.
BALLOON INFLATION
BASELINE
1 5 0 .mm/s/
I
, . . , ,
I
,
, , , , , , A
I
I
I
,
,
I
,
, ,
I
I
,
,
,
, ,
,
, ,
I
, , ,
,
, , , , , , , , ,
,?e!
P(n/
7 t t
I
. . . . . . . . . . . . . . .._ . ....................
I
Ao
.........
........
..
................... .............. ..........
Fig. 2. On the left baseline is the electrocardiogram prior to balloon inflation. During balloon inflation there is ST segment alternans (arrows) with a new left bundle branch block and marked left axis deviation. These changes resolved within 1 minute after balloon deflation. Abbreviations are as in Fig. 1.
RCA. Balloon angioplasty of the mid-LAD lesion was performed first. During the first balloon inflation the patient developed ST alternans, most prominent in lead V5, without widening of the QRS complex. She also developed severe substernal chest pain typical for her angina. Because of a local dissection of the mid-LAD, 2
additional inflations of a shorter duration were performed with no ST alternans. Subsequently successful PTCA of the distal LAD stenosis and proximal RCA was performed. A 70-year-old male with no previous cardiac history was admitted with unstable angina. He was receiving
ST Segment Alternans During PTCA
intranvenous heparin, intravenous nitroglycerine, aspirin, diltiazem, hydrochlorothiazide, triamterene, and his usual dose of regular/NPH insulin. Angiography showed an isolated 90% stenosis of the mid-LAD, with no evidence for collateral circulation to the distal vessel. PTCA was undertaken. During the first angioplasty balloon inflation the patient developed ST segment elevation, most pronounced in lead I, and then developed ST segment alternans. Those ECG changes, as well as the chest pain, resolved shortly after balloon deflation. Two subsequent balloon inflations, for shorter periods, resulted in no ST alternans. As noted in patients 1-3, no changes in arterial pressure or heart rate were noted.
47
emia as a common etiology for both. In contrast to ST alternans described in animal models [ l ] or variant angina [4], the findings did not follow a premature ventricular beat in these patients. The occurrence of ST alternans in the absence of a long QT interval appears to be invariably associated with ischemia [5]. Electrical alternans on the surface electrocardiogram can be caused by alternation of the action potential configuration [ 1,9]. Transmembrane or intracellular calcium movement may play a major role in the mechanism of electrical alternans. A relationship between ECG electrical alternans and mechanical alternans has been described, and it has been suggested that electrical alternans is due to altered Ca2+ transients associated with changes in intrinsic contractility [lo]. None of DISCUSSION the patients in this report had alternans of the central ST segment alternans is found in 71-93% of animals aortic pressure during electrical alternans. The lack of subjected to experimental coronary occlusion [4]. The alternans of aortic pressure should not necessarily be initiation of ST alternans may start spontaneously but, taken as lack of evidence of altered contractility, as this provided there is overt ST elevation, it is almost invari- is an insensitive measure of left ventricular contractility. ably in the wake of premature ventricular depolarization. Certainly, more direct measurements of contractility There is substantial agreement that the development of would have demonstrated some change during prolonged ventricular arrhythmias coincides with the maximum ex- balloon inflation of the LAD in these patients. Thus, if pression of the ST alternans. This has been described in the ECG alternans is due to altered LV contractility, this acute coronary artery occlusion in experimental animals was not detectable in this group of patients. Perhaps the [ l ] and clinically in patients with variant angina [4]. best unifying mechanism for ST alternans in this series is ST alternans during coronary angioplasty has been de- ischemia involving a large amount of myocardium. All scribed infrequently [6], even with careful scrutiny of the patients had PTCA of the LAD, and 1 had additional ECG during PTCA [7,8]. Since ST alternans has been so collaterals from the LAD to an occluded RCA. strongly associated with the presence of ventricular arIt has been reported that verapamil can suppress elecrhythmias, ST alternans during PTCA may be clinically trical alternans in animals [ 1 11. It is notable that 2 out of important as a harbinger of ventricular ectopy. 4 of these patients received no calcium channel blocking Ischemia involving a large area of myocardium has agents prior to PTCA. The frequent use of calcium chanbeen present in patients with ST alternans, variant an- nel blockers prior to balloon angioplasty in many patients gina, and in animal models of coronary occlusion with may interfere with the mechanism leading to electrical ST alternans. alternans, explaining why ST alternans is so infrequently In our patients, 3 out of 4 had severe 2-vessel disease, noticed during angioplasty procedures. and the fourth patient had no visible collateral circulation to the area supplied by the mid-LAD. Total coronary occlusion during PTCA resulted in ischemia involving a REFERENCES large area of myocardial tissue. Interestingly, all of our 1. Konta T, Ikeda K, Yamaki M, Nakamura K , Honma K, Kubota patients had ST segment alternans occur during the first I, Yasui S: Significance of discordant ST alternans in ventricular balloon inflation in the proximal or mid-LAD. Repeat fibrillation. Circulation 82:2 185 -2 189, 1990. 2. Hashimoto H, Asano M, Nakashima M: Potentiating effects of a inflations, though shorter in duration, did not result in ventricular premature beat on the alternation of the ST-T complex ST alternans. The only other report of ST alternans durof epicardial electrocardiograms and the incidence of ventricular ing PTCA involved proximal LAD occlusion without arrhythmias during acute coronary artery occlusion in dogs. J collateral flow [ 6 ] . Similarly no hemodynamic conseElectrocardiol 17:229-301, 1984. quence was associated with the ECG finding of ST al3. Kleber AG, Janse MJ, van Capelle FJL, Durrer D: Mechanism and time course of S-T and T-Q segment changes during acute ternans. regional myocardial ischemia in the pig heart determined by exOne patient developed transient left bundle branch tracellular and intracellular recordings. Circ Res 42:603-613, block with LAD balloon occlusion. There was no change 1978. in R wave height, and no change in blood pressure was 4. Turitto G, El-Sherif N: Alternans of the ST segment in variant noted. Prolongation of intraventricular conduction may angina. Chest 93:587-591, 1988. be associated with electrical alternans because of isch- 5. Schwartz PJ. Malliani A: Electrical alternation of the T-wave:
48
Sochanski et al.
clinical and experimental evidence of its relationship with the sympathetic nervous system and with the long QT syndrome. Am Heart J 89:45-50, 1975. 6. Joyal M, Feldman RL, Pepine CJ: ST-segment alternans during percutaneous transluminal coronary angioplasty . Am J Cardiol 54:9 15-9 16, 1984. 7. Feldman T, Chua KG, Childers RW: R wave of the surface and intracoronary electrocardiogram during acute coronary artery occlusion. Am J Cardiol 58985-890, 1986. 8. Feldman T, Childers RW, Chua KG: Optimal ECG monitoring during percutaneous transluminal coronary angioplasty of the left anterior descending artery. Cathet Cardiovasc Diag 13:271-174, 1987.
9. Nakashima M, Hashimoto H, Kanamaru M, Nagaya T, Hashizume M, Oishi H: Experimental studies and clinical report on the electrical alternans of ST segment during myocardial ischemia. Jpn Heart J 19:396-408, 1978. 10. Uno K: Mechanisms of pulsus alternans: Its relation to alteration of regional contraction and elevated ST segment. Am Heart J 122:1694-1700, 1991. 11. Hirata Y, Kodama I, Iwamura N, Shimizu T, Toyama J, Yamada K: Effects of verapamil on canine Purkinje fibers and ventricular muscle fibers with particular reference to the alternation of action potential duration after a sudden increase in driving rate. Cardiovasc Res 13:l-8, 1979.
ST Segment Alternans During Coronary Angioplasty Mirek Sochanski, MD, Ted Feldman, MD, FSCAI, K.G. Chua, MD, Andrew Benn, MD, and Rory Childers, MUD Four patients with severe proximal or mid-LAD stenosis were noted to have ST alternans during balloon angioplasty. Neither mechanical alternans nor increased ventricular ectopy were noted. In contrast to prior descriptions in animals or patients with variant angina, ST alternans did not occur following a premature ventricular contraction. Frequent use of calcium channel blockers during PTCA may interfere with the mechanism leading to electrical alternans and its consequences as seen in animal studies, accounting for the low frequency with which this phenomenon is noted during PTCA. 0 1992 Wiley-Liss,
Inc.
Key words: electrocardiogram, PTCA, myocardial ischemia
INTRODUCTION
Electrical alternans of the ST segment have been well characterized following experimental coronary occlusion in animals [l-31 and, clinically, in patients with variant angina [4]or a prolonged QT interval [5]. It has been demonstrated that ST alternans may be associated with ventricular arrhythmias [I]. This report described ST segment alternans that occurred in 4 patients during percutaneous transluminal coronary angioplasty (PTCA) . A 39-year-old male with stable exertional angina, prior inferior myocardial infarction, and a positive stress test was referred for cardiac catheterization. Resting ECG showed Q waves in the inferior leads, nonspecific ST-T segment changes, and a normal QT interval. Coronary angiography demonstrated a totally occluded proximal right coronary artery (RCA), eccentric 90 percent mid-left anterior descending artery (LAD) stenosis, and 80% mid-obtuse marginal stenosis. Good collateral flow from the LAD to the distal RCA was present. Left ventricular angiography showed preserved overall left ventricular function with severe hypokinesis of the inferior and inferobasal walls. Medications included atenolol, isosorbide dinitrate, allopurinol, acetaminophen with codeine, and triazolam. PTCA of the LAD and obtuse marginal was planned. The LAD lesion was crossed without difficulty, and 1 inflation of 5 atmospheres for 100 seconds was performed. Eighty-six seconds into the balloon inflation, ST segment alternans appeared. This persisted for 1 minute and 55 seconds after balloon deflation. The most pronounced ECG changes were observed in lead I (Fig. 1). During ST alternans, no changes in blood pressure or heart rate were noted. The patient experienced mild substernal chest pain typical for his anginal pain that re0 1992 Wiley-Liss, Inc.
solved soon after balloon deflation. Next, successful PTCA of the obtuse marginal artery was performed but no ST alternans occurred, although the patient had ST segment depression and similar substernal chest pain. Subsequently, a 12-lead ECG remained unchanged and a signal-averaged ECG was normal. A 44-year-old female returned with unstable angina 2 months after uncomplicated PTCA of a proximal LAD stenosis. She was treated with intravenous nitroglycerine, heparin, nifedipine, and enteric aspirin. Repeat angiography showed recurrence of the proximal LAD stenosis assessed to be 90%. PTCA of the LAD was undertaken. During the first inflation, after 90 seconds the patient developed ST segment alternans, best seen in lead I, and left bundle branch block with left axis deviation (Fig. 2). This was followed by her usual anginal pain, which resolved shortly after balloon deflation. Two other inflations that were performed subsequently for a shorter duration did not cause ST alternans. A 65-year-old woman with no previous cardiac history was admitted with unstable angina. She was treated with heparin and intravenous nitroglycerine. Cardiac catheterization showed a 95% eccentric mid-LAD lesion, followed by 85% distal LAD stenosis, 80% proximal ramus intermedius lesion, and 70-80% stenosis of the proximal
From the University of Chicago Hospitals, Department of Medicine, Section of Cardiology, Hans Hecht Hernodynamics Laboratory, Chicago, Illinois.
Received January 15, 1992; revision accepted April 7, 1992. Address reprint requests to Ted Feldman, M.D., University of Chicago Hospitals, 5841 S. Maryland Avenue, Mail Code-5076. Chicago, IL 60637.
46
-
Sochanski et al.
BALLOON INFLATION
BASELINE
........................................ I II
,,,,,,
, ,
, , , , , ,,-, , , , , , , , , , , , ,/ , , , , , , , , , , , I
I
,
,
,
I
I
,
,
,, ,, ,,,
,
I
,
,
,
, , , ,, , ,
.?,5, .'?m/
Ao
-
Fig. 1. On the left is the baseline electrocardiogram prior to balloon inflation. Frontal ECG leads and the aortic pressure (Ao) recorded from the guiding catheter are displayed. During balloon inflation there is ECG ST alternans with minimal QRS widening, most prominent in lead I (arrows), with no hemodynamic changes and no QRS alternans.
BALLOON INFLATION
BASELINE
1 5 0 .mm/s/
I
, . . , ,
I
,
, , , , , , A
I
I
I
,
,
I
,
, ,
I
I
,
,
,
, ,
,
, ,
I
, , ,
,
, , , , , , , , ,
,?e!
P(n/
7 t t
I
. . . . . . . . . . . . . . .._ . ....................
I
Ao
.........
........
..
................... .............. ..........
Fig. 2. On the left baseline is the electrocardiogram prior to balloon inflation. During balloon inflation there is ST segment alternans (arrows) with a new left bundle branch block and marked left axis deviation. These changes resolved within 1 minute after balloon deflation. Abbreviations are as in Fig. 1.
RCA. Balloon angioplasty of the mid-LAD lesion was performed first. During the first balloon inflation the patient developed ST alternans, most prominent in lead V5, without widening of the QRS complex. She also developed severe substernal chest pain typical for her angina. Because of a local dissection of the mid-LAD, 2
additional inflations of a shorter duration were performed with no ST alternans. Subsequently successful PTCA of the distal LAD stenosis and proximal RCA was performed. A 70-year-old male with no previous cardiac history was admitted with unstable angina. He was receiving
ST Segment Alternans During PTCA
intranvenous heparin, intravenous nitroglycerine, aspirin, diltiazem, hydrochlorothiazide, triamterene, and his usual dose of regular/NPH insulin. Angiography showed an isolated 90% stenosis of the mid-LAD, with no evidence for collateral circulation to the distal vessel. PTCA was undertaken. During the first angioplasty balloon inflation the patient developed ST segment elevation, most pronounced in lead I, and then developed ST segment alternans. Those ECG changes, as well as the chest pain, resolved shortly after balloon deflation. Two subsequent balloon inflations, for shorter periods, resulted in no ST alternans. As noted in patients 1-3, no changes in arterial pressure or heart rate were noted.
47
emia as a common etiology for both. In contrast to ST alternans described in animal models [ l ] or variant angina [4], the findings did not follow a premature ventricular beat in these patients. The occurrence of ST alternans in the absence of a long QT interval appears to be invariably associated with ischemia [5]. Electrical alternans on the surface electrocardiogram can be caused by alternation of the action potential configuration [ 1,9]. Transmembrane or intracellular calcium movement may play a major role in the mechanism of electrical alternans. A relationship between ECG electrical alternans and mechanical alternans has been described, and it has been suggested that electrical alternans is due to altered Ca2+ transients associated with changes in intrinsic contractility [lo]. None of DISCUSSION the patients in this report had alternans of the central ST segment alternans is found in 71-93% of animals aortic pressure during electrical alternans. The lack of subjected to experimental coronary occlusion [4]. The alternans of aortic pressure should not necessarily be initiation of ST alternans may start spontaneously but, taken as lack of evidence of altered contractility, as this provided there is overt ST elevation, it is almost invari- is an insensitive measure of left ventricular contractility. ably in the wake of premature ventricular depolarization. Certainly, more direct measurements of contractility There is substantial agreement that the development of would have demonstrated some change during prolonged ventricular arrhythmias coincides with the maximum ex- balloon inflation of the LAD in these patients. Thus, if pression of the ST alternans. This has been described in the ECG alternans is due to altered LV contractility, this acute coronary artery occlusion in experimental animals was not detectable in this group of patients. Perhaps the [ l ] and clinically in patients with variant angina [4]. best unifying mechanism for ST alternans in this series is ST alternans during coronary angioplasty has been de- ischemia involving a large amount of myocardium. All scribed infrequently [6], even with careful scrutiny of the patients had PTCA of the LAD, and 1 had additional ECG during PTCA [7,8]. Since ST alternans has been so collaterals from the LAD to an occluded RCA. strongly associated with the presence of ventricular arIt has been reported that verapamil can suppress elecrhythmias, ST alternans during PTCA may be clinically trical alternans in animals [ 1 11. It is notable that 2 out of important as a harbinger of ventricular ectopy. 4 of these patients received no calcium channel blocking Ischemia involving a large area of myocardium has agents prior to PTCA. The frequent use of calcium chanbeen present in patients with ST alternans, variant an- nel blockers prior to balloon angioplasty in many patients gina, and in animal models of coronary occlusion with may interfere with the mechanism leading to electrical ST alternans. alternans, explaining why ST alternans is so infrequently In our patients, 3 out of 4 had severe 2-vessel disease, noticed during angioplasty procedures. and the fourth patient had no visible collateral circulation to the area supplied by the mid-LAD. Total coronary occlusion during PTCA resulted in ischemia involving a REFERENCES large area of myocardial tissue. Interestingly, all of our 1. Konta T, Ikeda K, Yamaki M, Nakamura K , Honma K, Kubota patients had ST segment alternans occur during the first I, Yasui S: Significance of discordant ST alternans in ventricular balloon inflation in the proximal or mid-LAD. Repeat fibrillation. Circulation 82:2 185 -2 189, 1990. 2. Hashimoto H, Asano M, Nakashima M: Potentiating effects of a inflations, though shorter in duration, did not result in ventricular premature beat on the alternation of the ST-T complex ST alternans. The only other report of ST alternans durof epicardial electrocardiograms and the incidence of ventricular ing PTCA involved proximal LAD occlusion without arrhythmias during acute coronary artery occlusion in dogs. J collateral flow [ 6 ] . Similarly no hemodynamic conseElectrocardiol 17:229-301, 1984. quence was associated with the ECG finding of ST al3. Kleber AG, Janse MJ, van Capelle FJL, Durrer D: Mechanism and time course of S-T and T-Q segment changes during acute ternans. regional myocardial ischemia in the pig heart determined by exOne patient developed transient left bundle branch tracellular and intracellular recordings. Circ Res 42:603-613, block with LAD balloon occlusion. There was no change 1978. in R wave height, and no change in blood pressure was 4. Turitto G, El-Sherif N: Alternans of the ST segment in variant noted. Prolongation of intraventricular conduction may angina. Chest 93:587-591, 1988. be associated with electrical alternans because of isch- 5. Schwartz PJ. Malliani A: Electrical alternation of the T-wave:
48
Sochanski et al.
clinical and experimental evidence of its relationship with the sympathetic nervous system and with the long QT syndrome. Am Heart J 89:45-50, 1975. 6. Joyal M, Feldman RL, Pepine CJ: ST-segment alternans during percutaneous transluminal coronary angioplasty . Am J Cardiol 54:9 15-9 16, 1984. 7. Feldman T, Chua KG, Childers RW: R wave of the surface and intracoronary electrocardiogram during acute coronary artery occlusion. Am J Cardiol 58985-890, 1986. 8. Feldman T, Childers RW, Chua KG: Optimal ECG monitoring during percutaneous transluminal coronary angioplasty of the left anterior descending artery. Cathet Cardiovasc Diag 13:271-174, 1987.
9. Nakashima M, Hashimoto H, Kanamaru M, Nagaya T, Hashizume M, Oishi H: Experimental studies and clinical report on the electrical alternans of ST segment during myocardial ischemia. Jpn Heart J 19:396-408, 1978. 10. Uno K: Mechanisms of pulsus alternans: Its relation to alteration of regional contraction and elevated ST segment. Am Heart J 122:1694-1700, 1991. 11. Hirata Y, Kodama I, Iwamura N, Shimizu T, Toyama J, Yamada K: Effects of verapamil on canine Purkinje fibers and ventricular muscle fibers with particular reference to the alternation of action potential duration after a sudden increase in driving rate. Cardiovasc Res 13:l-8, 1979.
