| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
(Circulation. 2007;116:1647-1652.)
© 2007 American Heart Association, Inc.
Arrhythmia/Electrophysiology |
From the TIMI Study Group, Cardiovascular Division, Department of Medicine, Brigham and Womens Hospital, and Harvard Medical School, Boston, Mass (B.M.S., D.A.M., S.A.M., C.M.H., C.H.M., E.B.); Chaim Sheba Medical Center, Tel Hashomer, Israel (H.H.); CV Therapeutics, Palo Alto, Calif (L.B.); Medisch Spectrum Twente, Enschede, The Netherlands (P.M.); HeartLung Centre, Nijmegen, The Netherlands (F.W.A.V.); and Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minn (B.J.G.).
Correspondence to Benjamin M. Scirica, MD, MPH, TIMI Study Group, Cardiovascular Division, Brigham and Womens Hospital, 75 Francis St, Boston, MA 02115. E-mail bscirica{at}partners.org
Received June 29, 2007; accepted August 7, 2007.
| Abstract |
|---|
|
|
|---|
Methods and Results— The Metabolic Efficiency With Ranolazine for Less Ischemia in Non–ST-Elevation Acute Coronary Syndrome (MERLIN)–Thrombolysis in Myocardial Infarction (TIMI) 36 (MERLIN-TIMI 36) trial randomized 6560 patients hospitalized with a non–ST-elevation acute coronary syndrome to ranolazine or placebo in addition to standard therapy. Continuous ECG (Holter) recording was performed for the first 7 days after randomization. A prespecified set of arrhythmias were evaluated by a core laboratory blinded to treatment and outcomes. Of the 6560 patients in MERLIN-TIMI 36, 6351 (97%) had continuous ECG recordings that could be evaluated for arrhythmia analysis. Treatment with ranolazine resulted in significantly lower incidences of arrhythmias. Specifically, fewer patients had an episode of ventricular tachycardia lasting
8 beats (166 [5.3%] versus 265 [8.3%]; P<0.001), supraventricular tachycardia (1413 [44.7%] versus 1752 [55.0%]; P<0.001), or new-onset atrial fibrillation (55 [1.7%] versus 75 [2.4%]; P=0.08). In addition, pauses
3 seconds were less frequent with ranolazine (97 [3.1%] versus 136 [4.3%]; P=0.01).
Conclusions— Ranolazine, an inhibitor of late INa, appears to have antiarrhythmic effects as assessed by continuous ECG monitoring of patients in the first week after admission for acute coronary syndrome. Studies specifically designed to evaluate the potential role of ranolazine as an antiarrhythmic agent are warranted.
Key Words: coronary disease antiarrhythmia agents tachyarrhythmias
| Introduction |
|---|
|
|
|---|
Clinical Perspective p 1652
By preferentially inhibiting late INa, ranolazine has been shown in single cells, isolated hearts, and animal models to reduce intracellular sodium and calcium overload caused by induced ischemia, heart failure, or reactive oxygen species that prolong INa.4,8,9 Moreover, in contrast to a drug like sotalol, the addition of ranolazine in these experimental models suppresses early afterdepolarization and other proarrhythmic electrophysiological phenomena.8 The potential antiarrhythmic actions of ranolazine, however, have yet to be evaluated in humans. We therefore investigated the incidence of arrhythmias, as detected by continuous ECG (cECG) monitoring, as part of a randomized, double-blind, placebo-controlled trial.10,11
| Methods |
|---|
|
|
|---|
The primary outcome of the cECG assessment was the incidence of clinically significant arrhythmias as detected by cECG monitoring that were prespecified as an episode of ventricular tachycardia at least 3 beats in length, any supraventricular tachycardia >120 bpm and lasting at least 4 beats, new-onset atrial fibrillation, an episode of bradycardia of <45 bpm lasting at least 4 beats, complete heart block, or a ventricular pause
2.5 seconds. Ventricular tachycardias were subsequently categorized according to current guidelines12 by length (at least 4 beats, at least 8 beats, and sustained [>30 seconds]), as well as by morphology for episodes lasting
8 beats (monomorphic versus polymorphic). Ventricular pauses were subsequently categorized by length (lasting
3 seconds) and by the principal mechanism of action (sinus node dysfunction, atrioventricular node dysfunction, or other mechanism).
The mean clinical follow-up was
12 months. A blinded clinical events committee adjudicated sudden cardiac death, which was defined as a sudden, unexpected death that was either (1) witnessed and occurring within 60 minutes from the onset of new symptoms and in the absence of a clear cause other than cardiovascular or (2) unwitnessed and occurring within 24 hours of being observed alive in the absence of preexisting progressive circulatory failure or other noncardiovascular causes of death.
Statistical Analysis
All arrhythmia analyses were based on patients with evaluable cECG data. Continuous data were compared with a t test for normally distributed data and a Wilcoxon rank-sum test for nonnormally distributed data. Dichotomous variables were compared with a
2 test. All analyses comparing treatment strategy and the incidence of arrhythmias were performed with a Cochran-Mantel-Haenszel test stratifying by the intention to use an early invasive strategy before randomization.10 Hazard ratios and 95% confidence intervals (CIs) were estimated by use of a Cox proportional-hazards regression model. Mortality rates are presented as Kaplan-Meier failure rates at 12 months.
The authors had full access to and take full responsibility for the integrity of the data. All authors have read and agree to the manuscript as written.
| Results |
|---|
|
|
|---|
|
Treatment with ranolazine resulted in a significantly lower incidence of tachyarrhythmias compared with placebo (Table 2). Specifically, fewer patients assigned to ranolazine had an episode of ventricular tachycardia lasting
4 or
8 beats compared with placebo (the Figure). Few patients in MERLIN-TIMI 36 had either sustained ventricular tachycardia lasting
30 seconds or polymorphic ventricular tachycardia lasting
8 beats during cECG monitoring, and no difference existed between patients treated with ranolazine or placebo (Table 2). Sustained polymorphic ventricular tachycardia was detected on cECG in 10 patients (0.32%) assigned to ranolazine and 7 patients (0.22%) assigned to placebo (P=0.46). Two of these cases were reported clinically as torsade de pointes, 1 in each treatment group. Of the 17 patients with sustained polymorphic tachycardia, 15 cases occurred in the setting of ST depression or elevation. Three cases occurred with a preceding QT interval >600 milliseconds, 2 of which had concurrent ischemia. One of these 3 patients was assigned to placebo; 2 were assigned to ranolazine.
|
|
The incidence of ventricular tachycardia lasting
8 beats was similar in patients with or without ischemia detected on cECG monitoring (
1-mm ST depression or elevation lasting
1 minute) (107 of 1351 [7.3%] versus 324 of 4569 [6.2%]; P=0.37) with a consistent reduction in the rate of ventricular tachycardia
8 beats with ranolazine among patients with ischemia (6.3% versus 8.3%; relative risk [RR], 0.76; 95% CI, 0.52 to 1.10; P=0.12) or no ischemia (5.0% versus 8.3%; RR, 0.60; 95% CI, 0.48 to 0.74; P<0.001) (P for interaction=0.29). No significant difference existed between treatment groups in the number of patients with sudden cardiac death (56 [1.7%] in the ranolazine group versus 65 [1.8%] in the placebo group).
Among several high-risk subgroups, including patients with prior heart failure, reduced left ventricular function, prolonged QTc interval at baseline, and high TIMI Risk Score (5–7), a consistent reduction was present in the incidence of ventricular tachycardias lasting
8 beats in patients treated with ranolazine with no difference in sudden cardiac death (Table 3).
|
In addition, patients treated with ranolazine were less likely to have an episode of supraventricular tachycardia lasting
4 beats at a rate of >120 bpm, new-onset atrial fibrillation, ventricular pauses
2.5 seconds or
3 seconds, and a bradycardic episode of <45 bpm lasting
4 beats (Tables 2 and 4
).
|
| Discussion |
|---|
|
|
|---|
This is the first clinical report of the effect of ranolazine on the incidence of cardiac arrhythmias, and it supports the experimental data that have identified several potential antiarrhythmic properties of ranolazine.4,8,13 The electrophysiological basis for drug-related suppression or induction of arrhythmias is complex. Contributory factors include conditions (congenital, acquired, and drug induced) that alter ion channel function, dispersion of repolarization, and pathological structural changes in the myocardium that alter electric impulse conduction. The 2 ion channel currents that are inhibited by ranolazine at clinically therapeutic concentrations (2 to 6 µmol/L) are late INa (ranolazine IC50=6 µmol/L) and the delayed rectifier potassium current (IKr) (IC50=12 µmol/L).8 Inhibition of IKr prolongs ventricular action potential duration, whereas inhibition of late INa has the opposite effect and shortens the action potential duration. The net effect of ranolazine on action potential duration depends on the relative magnitude of reductions in inward (INa) and outward (IKr) currents during repolarization.6 In normal ventricular epicardial and endocardial myocardium, the reduction in IKr predominates; thus, the net effect is that ranolazine lengthens the action potential duration in epicardium and endocardium. In contrast, in midmyocardium (M cells) and Purkinje fibers, the reduction in INa predominates, and ranolazine actually reduces action potential duration in these tissues. In addition to its direct effects to inhibit late INa and IKr, ranolazine has been shown in preclinical studies to reduce calcium overload induced by ischemia and reperfusion and thereby to attenuate electric dysfunction that is secondary to elevation of the intracellular calcium concentration.9,13
The net effect of ranolazine on the surface ECG is the known small prolongation of QTc by 2 to 6 ms.6 However, prolongation of QTc in the absence of other changes may not reflect the underlying electric susceptibility of the myocardium to arrhythmias, and in particular ventricular tachycardia and torsade de pointes. In the report by Antzelevitch et al,5 sotalol, an inhibitor of IKr, both prolonged action potential duration and increased the risk of early afterdepolarization, which can precipitate torsade de pointes. In that experimental study, ranolazine suppressed sotalol-induced prolongation of the action potential and early afterdepolarization. In canine ventricular wedge preparations, ranolazine, in contrast to sotalol,14 reduced another proarrhythmic substrate, transmural dispersion of repolarization.8 In this experimental model, treatment with ranolazine did not induce torsade de pointes and prevented ventricular tachycardia induced by programmed electric stimulation. Thus, despite the observation that ranolazine lengthens the QTc interval, preclinical evidence suggests that the overall electrophysiological action of the drug is not to increase but to suppress arrhythmic activity. The potential clinical relevance of these experimental findings is supported by the present results of the MERLIN-TIMI 36 trial, which demonstrate that ranolazine use was associated with a decrease rather than an increase in the incidence of arrhythmic activity in cECG recordings.
The use of most antiarrhythmic agents is limited by the risk of life-threatening arrhythmias or toxicity with prolonged exposure. Class Ia, Ic, and III antiarrhythmic agents suppress ventricular ectopy or reduce atrial fibrillation, but several, particularly class Ia and Ic agents such as flecainide and encainide and class III agents such as sotalol, may increase susceptibility to life-threatening arrhythmia14 or actually increase the risk of death after MI.15–17 In the patients in MERLIN-TIMI 36 with cECG recordings, ranolazine reduced nonsustained ventricular arrhythmias. Sustained polymorphic tachycardia occurred infrequently during the high-risk period of the first 7 days in MERLIN-TIMI 36 and in almost all cases was in the presence of ongoing ischemia detected on cECG. Although this analysis does not exclude the potential for drug-induced arrhythmia, we find no evidence for a significant excess risk of polymorphic ventricular tachycardia with ranolazine during the time of cECG monitoring in these high-risk patients. Moreover, the numerically, but not statistically, lower incidence of sudden cardiac death in patients treated with ranolazine over the entire study period provides important data supporting the apparent safety of longer-term treatment with ranolazine in high-risk patients with established coronary artery disease.11
The primary objective of the MERLIN-TIMI 36 trial was to assess the effects of ranolazine on cardiovascular death and recurrent ischemic events. Although the effects on arrhythmias are intriguing, they are exploratory and warrant trials specifically designed to assess the potential effect of ranolazine as an antiarrhythmic agent. It is possible that the anti-ischemic effect of ranolazine contributed to the observed reduction in arrhythmia, but the similar reduction in the incidence of ventricular tachycardia with ranolazine in patients with and without ischemia as detected on cECG suggests that ranolazine has direct antiarrhythmic properties.
The effects of ranolazine to inhibit late INa (and calcium overload) and IKr are plausible mechanisms by which the drug may reduce the risk of both supraventricular and ventricular tachycardias.8 The mechanism to explain the reduction of bradyarrhythmias, however, remains to be determined. Agents such as ß-blockers, calcium channel blockers, amiodarone, and lidocaine suppress tachycardias but typically, and in contrast to ranolazine, decrease heart rate and actually increase bradyarrhythmias. We found no imbalance among antianginal agents with negative chronotropic properties to potentially explain this finding. Further research examining the effects of ranolazine on pacemaker activity and atrioventricular nodal conduction is needed to understand better the observed reduction in bradyarrhythmias by ranolazine.
| Conclusions |
|---|
|
|
|---|
| Acknowledgments |
|---|
MERLIN-TIMI 36 was supported by CV Therapeutics.
Disclosures
The TIMI Study Group reports receiving significant research grant support from Accumetrics, Amgen, AstraZeneca, Bayer Healthcare, Beckman Coulter, Biosite, Bristol-Myers Squibb, CV Therapeutics, Eli Lilly, GlaxoSmithKline, Inotek Pharmaceuticals, Integrated Therapeutics, Merck & Co, Merck-Schering Plough Joint Venture, Millennium Pharmaceuticals, Novartis Pharmaceuticals, Nuvelo, Ortho-Clinical Diagnostics, Pfizer, Roche Diagnostics, Sanofi-Aventis, Sanofi-Synthelabo, and Schering-Plough. Dr Scirica reports receiving honoraria for educational presentations from CV Therapeutics. Dr Morrow reports receiving honoraria for educational presentations from CV Therapeutics and Sanofi-Aventis, serving as a consultant for GlaxoSmithKline and Sanofi-Aventis, and being on an advisory board for Genentech. Dr Belardinelli is an employee of and owns stock in CV Therapeutics. Drs Hod, Molhoek, Hedgepeth, and Verheugt report receiving research support from CV Therapeutics. Dr Gersh reports being on an advisory board of and owns stock in CV Therapeutics. Dr Braunwald reports receiving honoraria from and serving as a consultant to AstraZeneca, Bayer AG, Daichii Sankyo, Merck, Pfizer, and Schering-Plough. The other authors report no conflicts.
| References |
|---|
|
|
|---|
2. Chaitman BR, Skettino SL, Parker JO, Hanley P, Meluzin J, Kuch J, Pepine CJ, Wang W, Nelson JJ, Hebert DA, Wolff AA. Anti-ischemic effects and long-term survival during ranolazine monotherapy in patients with chronic severe angina. J Am Coll Cardiol. 2004; 43: 1375–1382.
3. Stone PH, Gratsiansky NA, Blokhin A, Huang IZ, Meng L. Antianginal efficacy of ranolazine when added to treatment with amlodipine: the ERICA (Efficacy of Ranolazine in Chronic Angina) trial. J Am Coll Cardiol. 2006; 48: 566–575.
4. Song Y, Shryock JC, Wu L, Belardinelli L. Antagonism by ranolazine of the pro-arrhythmic effects of increasing late INa in guinea pig ventricular myocytes. J Cardiovasc Pharmacol. 2004; 44: 192–199.[CrossRef][Medline] [Order article via Infotrieve]
5. Antzelevitch C, Belardinelli L, Zygmunt AC, Burashnikov A, Di Diego JM, Fish JM, Cordeiro JM, Thomas G. Electrophysiological effects of ranolazine, a novel antianginal agent with antiarrhythmic properties. Circulation. 2004; 110: 904–910.
6. Chaitman BR. Ranolazine for the treatment of chronic angina and potential use in other cardiovascular conditions. Circulation. 2006; 113: 2462–2472.
7. Tani M, Neely JR. Role of intracellular Na+ in Ca2+ overload and depressed recovery of ventricular function of reperfused ischemic rat hearts: possible involvement of H+-Na+ and Na+-Ca2+ exchange. Circ Res. 1989; 65: 1045–1056.
8. Lee L, Campbell R, Scheuermann-Freestone M, Taylor R, Gunaruwan P, Williams L, Ashrafian H, Horowitz J, Fraser AG, Clarke K, Frenneaux M. Metabolic modulation with perhexiline in chronic heart failure: a randomized, controlled trial of short-term use of a novel treatment. Circulation. 2005; 112: 3280–3288.
9. Morrow DA, Scirica BM, Karwatowska-Prokopczuk E, Skene A, McCabe CH, Braunwald E. Evaluation of a novel anti-ischemic agent in acute coronary syndromes: design and rationale for the Metabolic Efficiency With Ranolazine for Less Ischemia in Non-ST-Elevation Acute Coronary Syndromes (MERLIN)-TIMI 36 trial. Am Heart J. 2006; 151: 1186.e1–e9.
10. Morrow DA, Scirica BM, Karwatowska-Prokopczuk E, Murphy SA, Budaj A, Varshavsky S, Wolff AA, Skene A, McCabe CH, Braunwald E, for the MERLIN-TIMI 36 Trial Investigators. Effects of ranolazine on recurrent cardiovascular events in patients with non-st-elevation acute coronary syndromes: the MERLIN-TIMI 36 randomized trial. JAMA. 2007; 297: 1775–1783.
11. Zipes DP, Camm AJ, Borggrefe M, Buxton AE, Chaitman B, Fromer M, Gregoratos G, Klein G, Moss AJ, Myerburg RJ, Priori SG, Quinones MA, Roden DM, Silka MJ, Tracy C, Smith SC Jr, Jacobs AK, Adams CD, Antman EM, Anderson JL, Hunt SA, Halperin JL, Nishimura R, Ornato JP, Page RL, Riegel B, Blanc JJ, Budaj A, Dean V, Deckers JW, Despres C, Dickstein K, Lekakis J, McGregor K, Metra M, Morais J, Osterspey A, Tamargo JL, Zamorano JL. ACC/AHA/ESC 2006 guidelines for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death: a report of the American College of Cardiology/American Heart Association Task Force and the European Society of Cardiology Committee for Practice Guidelines (Writing Committee to Develop Guidelines for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death): developed in collaboration with the European Heart Rhythm Association and the Heart Rhythm Society. Circulation. 2006; 114: e385–e484.[CrossRef][Medline] [Order article via Infotrieve]
12. Song Y, Shryock JC, Wagner S, Maier LS, Belardinelli L. Blocking late sodium current reduces hydrogen peroxide-induced arrhythmogenic activity and contractile dysfunction. J Pharmacol Exp Ther. 2006; 318: 214–222.
13. Shimizu W, McMahon B, Antzelevitch C. Sodium pentobarbital reduces transmural dispersion of repolarization and prevents torsades de pointes in models of acquired and congenital long QT syndrome. J Cardiovasc Electrophysiol. 1999; 10: 154–164.[Medline] [Order article via Infotrieve]
14. MacMahon S, Collins R, Peto R, Koster RW, Yusuf S. Effects of prophylactic lidocaine in suspected acute myocardial infarction: an overview of results from the randomized, controlled trials. JAMA. 1988; 260: 1910–1916.
15. Hambrecht R, Adams V, Erbs S, Linke A, Krankel N, Shu Y, Baither Y, Gielen S, Thiele H, Gummert JF, Mohr FW, Schuler G. Regular physical activity improves endothelial function in patients with coronary artery disease by increasing phosphorylation of endothelial nitric oxide synthase. Circulation. 2003; 107: 3152–3158.
16. Effect of the antiarrhythmic agent moricizine on survival after myocardial infarction: the Cardiac Arrhythmia Suppression Trial II Investigators. N Engl J Med. 1992; 327: 227–233.[Abstract]
17. Waldo AL, Camm AJ, deRuyter H, Friedman PL, MacNeil DJ, Pauls JF, Pitt B, Pratt CM, Schwartz PJ, Veltri EP. Effect of d-sotalol on mortality in patients with left ventricular dysfunction after recent and remote myocardial infarction: the SWORD Investigators: Survival With Oral d-Sotalol. Lancet. 1996; 348: 7–12.[CrossRef][Medline] [Order article via Infotrieve]
| Footnotes |
|---|
Clinical trial registration information—URL: http://www.clinicaltrials.gov. Unique identifier: NCT00099788.
Related Article:
Circulation 2007 116: 1643.
This article has been cited by other articles:
![]() |
A. K. Dhalla, W.-Q. Wang, J. Dow, J. C. Shryock, L. Belardinelli, A. Bhandari, and R. A. Kloner Ranolazine, an antianginal agent, markedly reduces ventricular arrhythmias induced by ischemia and ischemia-reperfusion Am J Physiol Heart Circ Physiol, November 1, 2009; 297(5): H1923 - H1929. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. K. Mason and J. P. DiMarco New Pharmacological Agents for Arrhythmias Circ Arrhythm Electrophysiol, October 1, 2009; 2(5): 588 - 597. [Full Text] [PDF] |
||||
![]() |
H. Hwang, J. M. Arcidi Jr, S. L. Hale, B. Z. Simkhovich, L. Belardinelli, A. K. Dhalla, J. C. Shryock, and R. A. Kloner Ranolazine as an Adjunct to Cardioplegia: A Potential New Therapeutic Application Journal of Cardiovascular Pharmacology and Therapeutics, June 1, 2009; 14(2): 125 - 133. [Abstract] [PDF] |
||||
![]() |
D. A. Morrow, B. M. Scirica, B. R. Chaitman, D. K. McGuire, S. A. Murphy, E. Karwatowska-Prokopczuk, C. H. McCabe, E. Braunwald, and for the MERLIN-TIMI 36 Investigators Evaluation of the Glycometabolic Effects of Ranolazine in Patients With and Without Diabetes Mellitus in the MERLIN-TIMI 36 Randomized Controlled Trial Circulation, April 21, 2009; 119(15): 2032 - 2039. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. Murphy and D. A. Eisner Regulation of Intracellular and Mitochondrial Sodium in Health and Disease Circ. Res., February 13, 2009; 104(3): 292 - 303. [Abstract] [Full Text] [PDF] |
||||
![]() |
W.-Q. Wang, C. Robertson, A. K. Dhalla, and L. Belardinelli Antitorsadogenic Effects of ({+/-})-N-(2,6-Dimethyl-phenyl)-(4[2-hydroxy-3-(2-methoxyphenoxy)propyl]-1-piperazine (Ranolazine) in Anesthetized Rabbits J. Pharmacol. Exp. Ther., June 1, 2008; 325(3): 875 - 881. [Abstract] [Full Text] [PDF] |
||||
![]() |
I. Savelieva and J. Camm Anti-arrhythmic drug therapy for atrial fibrillation: current anti-arrhythmic drugs, investigational agents, and innovative approaches Europace, June 1, 2008; 10(6): 647 - 665. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. M. Scheinman and E. Keung The Year in Review of Clinical Cardiac Electrophysiology J. Am. Coll. Cardiol., May 27, 2008; 51(21): 2075 - 2081. [Full Text] [PDF] |
||||
![]() |
Y. Song, J. C. Shryock, and L. Belardinelli An increase of late sodium current induces delayed afterdepolarizations and sustained triggered activity in atrial myocytes Am J Physiol Heart Circ Physiol, May 1, 2008; 294(5): H2031 - H2039. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. L. Eckhardt, T. C. Teelin, and C. T. January Is ranolazine an antiarrhythmic drug? Am J Physiol Heart Circ Physiol, May 1, 2008; 294(5): H1989 - H1991. [Full Text] [PDF] |
||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
Circulation Home | Subscriptions | Archives | Feedback | Authors | Help | AHA Journals Home | Search Copyright © 2007 American Heart Association, Inc. All rights reserved. Unauthorized use prohibited. |