| Abstract|| |
Introduction: Cardiac resynchronization therapy (CRT) is a proven therapeutic method in selected patients with heart failure and systolic dysfunction which increases left ventricular function and patient survival. We designed a study that included patients undergoing coronary artery bypass graft (CABG), with and without CRT-defibrillator (CRT-D) inserting and then measured its effects on these two groups. Patients and Methods: Between 2010 and 2013, we conducted a prospective cohort study on 100 coronary artery disease patients where candidate for CABG. Then based on the receiving CRT-D, the patients were categorized in two groups; Group 1 ( n = 48, with CRT-D insertion before CABG) and Group 2 ( n = 52 without receiving CRT-D). Thereafter both of these groups were followed-up at 1-3 months after CABG for mortality, hospitalization, atrial fibrillation (AF), echocardiographic assessment, and New York Heart Association (NYHA) class level. Results: The mean age of participants in Group 1 (48 male) and in Group 2 (52 male) was 58 ± 13 and 57 ± 12 respectively. Difference between Groups 1 and 2 in cases of mean left ventricular ejection fraction (LVEF) changes and NYHA class level was significant ( P > 0.05). Hospitalization ( P = 0.008), mortality rate ( P = 0.007), and AF were significantly different between these two groups. Conclusions: The results showed that the increase in LVEF and patient's improvement according to NYHA-class was significant in the first group, and readmission, mortality rate and AF was increased significantly in the second group.
Keywords: Cardiac resynchronization therapy; coronary artery bypass; heart failure
|How to cite this article:|
Karbasi Afshar R, Ramezani Binabaj M, Rezaee Zavareh MS, Saburi A, Ajudani R. Efficacy of cardiac resynchronization with defibrillator insertion in patients undergone coronary artery bypass graft: A cohort study of cardiac function. Ann Card Anaesth 2015;18:34-8
|How to cite this URL:|
Karbasi Afshar R, Ramezani Binabaj M, Rezaee Zavareh MS, Saburi A, Ajudani R. Efficacy of cardiac resynchronization with defibrillator insertion in patients undergone coronary artery bypass graft: A cohort study of cardiac function. Ann Card Anaesth [serial online] 2015 [cited 2020 Jun 4];18:34-8. Available from: http://www.annals.in/text.asp?2015/18/1/34/148319
| Introduction|| |
Coronary artery disease (CAD) increases the risk of a myocardial infarction and angina pectoris and reduces left ventricular output that causes sudden death and congestive heart failure (CHF).  CAD is responsible for two-third of heart failures. , The main cause of CHF exacerbation is uncontrolled ischemic disease. , One in five deaths in U.S is due to CAD. According to American Heart Association statistics in 2006, the prevalence of cardiovascular disease in US was 81.1 million that 17.6 million of them had CAD and among patients who had CAD the incidence of CHF was 5.8 million.  Drug therapy for CAD has many side effects. Also, interventional or surgical treatments in patients with multiple stenosis lesion or multiple vessel diseases do not have long-term relief for the patient and most of them remain symptomatic and may require surgery to be repeated.  Several clinical trials have been proven beneficial effects of coronary artery bypass graft (CABG) for CAD treatment. , Although myocardial dysfunction improves after CABG, left ventricular contractile dysfunction remains after surgery.  Left ventricular dysfunction is an independent factor for predicting postoperative mortality in patients undergo CABG  that can reduce cardiac output or increased mortality after surgery.  Lots of patients with postoperative left ventricular dysfunction require mechanical or inotropic support.  Cardiac resynchronization therapy (CRT) is a proven therapeutic method in selected patients with heart failure and systolic dysfunction, , which increases left ventricular function and patient survival. Although yet it's difficult to identify patients that will cause a favorable response to this treatment. , CRT has been successful in the treatment of advanced heart failure but in treating atrial fibrillation (AF) that adds up to 25% of cases after device insertion has not been better than drug therapy. However, the role of CRT-defibrillator (CRT-D) in this issue and to prevent the fibrillation that it is an increasing factor for death in the heart failure patients is highlighted.  Also the causes of sudden death in patients with chronic heart failure respectively are: Electromechanical dissociation (30%), primary Brady arrhythmia (30%), ventricular tachycardia, and/or fibrillation (40%) indicating the necessity of the CRT with the defibrillator in preventing sudden death in these patients.  At least part of the reduction in mortality in CRT is due to the hemodynamic correction. , Traditionally, the treatment of ischemia in patients with ischemic cardiomyopathy is surgery, and they are re-evaluating the need for CRT-D after 3 months (60-90 days). , We designed a prospective cohort study that included patients undergoing CABG, with and without CRT-D inserting and then measured its effects on these two groups.
| Patients And Methods|| |
Study design and population
Between 2010 and 2013, we conducted a prospective cohort study on 100 CAD patients who referred to our center and were candidate for CABG. Our sampling method was the census. New York Heart Association (NYHA) class level between II/III/IV, left ventricular ejection fraction (LVEF) ≤35%, QRS ≥120 ms (based on the electrocardiography) were the indications for receiving CRT-D and the patients who had a narrow QRS or NYHA class level I, were excluded from our study. Then based on the receiving CRT-D, the patients were categorized in two groups; Group 1 were 48 patients who received a CRT-D 24-48 h before CABG and Group 2 were 52 cases that underwent CABG without receiving a CRT-D. Thereafter both of these groups were followed-up at 1-3 months after CABG for mortality, hospitalization, AF, echocardiographic assessment, and NYHA class level. During the follow-up, Group 2 patients were also evaluated for requiring a CRT-D (based on the mentioned indications for receiving CRT-D). At one, two, and three times of follow-up. All patients in both groups were asked to refer to the clinic and filled questionnaires providing information concerning using of angiotensin converting enzyme (ACE) inhibitor, using of beta blocker.
This study was approved by the Ethics Committee of our university. Also, all of the participants signed an informed written consent before entering to this study.
Statistical analysis was done with SPSS, version 19 (IBM Inc. Chicago Illinois, USA, 2010). Mean ± standard deviation and frequency was used for expressing quantitative and qualitative variables respectively. For comparisons of quantitative variables, we used Student's t-test, and qualitative variables were compared with Chi-square (or Fisher's exact test). P < 0.05 was considered significant.
| Results|| |
Before the surgery
Finally according to the inclusion and exclusion criteria 100 patients were included in this project. The mean age of participants in Group 1 (n = 48) and in Group 2 (n = 52) was 58 ± 13 and 57 ± 12 respectively. There was not a statistical difference between these two groups in case of age (P > 0.05) and sex (P > 0.05) and both groups were matched in gender and age. [Table 1] represents some other baseline variables and characteristics of both groups. Based on this table both of the study groups are also matched in case of mean LVEF, and using of beta blocker and ACE inhibitor.
After the surgery
During the follow-up, no one of the Group 2 patients needed a CRT-D. Comparisons of two groups about LVEF changes, NYHA class level, hospitalization, the morality rate, and AF has been shown in [Table 2]. Mortality rate and AF was zero in Group 1 during the whole follow-up time. NYHA class level (P = 0.005) significantly decreased and ventricular ejection fraction changes (P = 0.001) significantly increased in Group 1. In Group 2, increase in LVEF changes was not statistically meaningful (P = 0.5) while NYHA class level significantly decreased (P = 0.01). Difference between Groups 1 and 2 in cases of LVEF changes and NYHA class level was significant (P > 0.05). Hospitalization (P = 0.008), mortality rate (P = 0.007), and AF (P = 0.003) was significantly different between these two groups.
|Table 2: Comparison of studied variables during the follow - up (in the row about LVEF changes, each column n was compared with the first ejection fraction) |
Click here to view
| Discussion|| |
The results showed that the increase in LVEF and patient's improvement according to NYHA-class was significant in the first group and readmission, mortality rate, and AF was increased significantly in the second group. All patients in the second group after 3 months were still remaining on the CRT placement list while none of the patients in the first group required CRT-D and readmission. No mortality and AF were reported in the first group. Implantable cardioverter defibrillator) reduces the risk of mortality due to arrhythmia that probably in the first phase after surgery is more likely in patient with low LVEF, two ventricular pacemaker reduces the risk of arrhythmias due to its positive effects on hemodynamics and modification of left ventricular function. Hemodynamic modification after CRT decreases the effects of stretching on myocardia  and balances the autonomic nervous system which can reduce postoperative arrhythmia and AF. Several studies have shown that biventricular pacemaker also reduces frequency of ventricular ectopia ,,, this, in turn decreases the onset of sustained ventricular arrhythmia, so justifies the positive hemodynamic effects, antiarrhythmia, AF, and no need for readmission in patients with CRT-D in a quarterly survey. , Cleland et al. in a study that conducted on 813 patients with class 3-4 heart failure and average follow-up 29.4 months showed that in addition to reducing the mortality and hospital readmission, LVEF and NYHA - class improvement rate in patients who were treated with CRT along with medical therapy was much higher than that of patients who received only medical treatment.  These findings were consistent with the results of our study, but unlike our study, they didn't use defibrillator with CRT-D. In a study performed on 1520 patients with advanced heart failure by accident use of CRT-CRT-D and drug therapy, the results showed that hospitalization risk in both intra-cardiac device groups were less than drug therapy and this reduction is further in type of defibrillator.  Another study by BRISTOW in the U.S. in the year 2000 on 2200 patients with class 3-4 heart failure, showed that compared to the use of CRT, CRT-D and optimal pharmacological therapy, CRT-D and CRT are significantly more successful than oral treatment in lowering mortality (up to 25%).  The results of this study were consistent with ours so that the mortality rate in group 1 was significantly lower than Group 2. Lindenfeld et al. In a study on 1520 patients with class 3-4 heart failure in 2006 that compared using of CRT and CRT-D with maximum oral therapy. The study showed that CRT, CRT-D compared to oral therapy on a follow-up of 12 months were with lower rates of mortality and hospitalization.  The results were consistent with ours too so that in addition to increased mortality rate in Group 2, 23% of this group in comparison with Group 1 needed for readmission due to heart failure or arrhythmia in the first 3 months. The conventional treatment of patients with Ischemic CMP is surgery and after 3 months (60-90 days) they are investigating the need for CRT-D. But in this study the candidate patients initially inserted CRT-D during CABG surgery and in Group 2 the similar patients underwent the surgery without CRT-D insertion. All patients were followed for 3 months. At the end, both two groups were compared. Increase in LVEF, patient's improvement according to NYHA-class, decrease in mortality rate and AF in Group 1 were significantly increased. Among the limitations of this study compared with the previous studies, low sample size and short time follow-up could be indicated that, fortunately, the interpretation of our results showed these limitations caused no significant difference.
| References|| |
Huikuri HV, Castellanos A, Myerburg RJ. Sudden death due to cardiac arrhythmias. N Engl J Med 2001;345:1473-82.
Baker DW, Jones R, Hodges J, Massie BM, Konstam MA, Rose EA. Management of heart failure. III. The role of revascularization in the treatment of patients with moderate or severe left ventricular systolic dysfunction. JAMA 1994;272:1528-34.
Hunt SA, Abraham WT, Chin MH, Feldman AM, Francis GS, Ganiats TG, et al
. 2009 Focused update incorporated into the ACC/AHA 2005 Guidelines for the Diagnosis and Management of Heart Failure in Adults A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines Developed in Collaboration With the International Society for Heart and Lung Transplantation. J Am Coll Cardiol 2009;53:e1-90.
Ghali JK, Kadakia S, Cooper R, Ferlinz J. Precipitating factors leading to decompensation of heart failure. Traits among urban blacks. Arch Intern Med 1988;148:2013-6.
Chin MH, Goldman L. Factors contributing to the hospitalization of patients with congestive heart failure. Am J Public Health 1997;87:643-8.
Thom T, Haase N, Rosamond W, Howard VJ, Rumsfeld J, Manolio T, et al
. Heart disease and stroke statistics - 2006 update: A report from the American Heart Association Statistics Committee and Stroke Statistics Subcommittee. Circulation 2006;113:e85-151.
Lavu M, Gundewar S, Lefer DJ. Gene therapy for ischemic heart disease. J Mol Cell Cardiol 2011;50:742-50.
Murphy ML, Hultgren HN, Detre K, Thomsen J, Takaro T. Treatment of chronic stable angina. A preliminary report of survival data of the randomized Veterans Administration cooperative study. N Engl J Med 1977;297:621-7.
Long-term results of prospective randomised study of coronary artery bypass surgery in stable angina pectoris. European Coronary Surgery Study Group. Lancet 1982;2:1173-80.
Milano CA, White WD, Smith LR, Jones RH, Lowe JE, Smith PK, et al.
Coronary artery bypass in patients with severely depressed ventricular function. Ann Thorac Surg 1993;56:487-93.
Ferguson TB Jr, Hammill BG, Peterson ED, DeLong ER, Grover FL, STS National Database Committee. A decade of change - risk profiles and outcomes for isolated coronary artery bypass grafting procedures, 1990-1999: A report from the STS National Database Committee and the Duke Clinical Research Institute. Society of Thoracic Surgeons. Ann Thorac Surg 2002;73:480-9.
Yau TM, Fedak PW, Weisel RD, Teng C, Ivanov J. Predictors of operative risk for coronary bypass operations in patients with left ventricular dysfunction. J Thorac Cardiovasc Surg 1999;118:1006-13.
Cleland JG, Daubert JC, Erdmann E, Freemantle N, Gras D, Kappenberger L, et al.
The effect of cardiac resynchronization on morbidity and mortality in heart failure. N Engl J Med 2005;352:1539-49.
Strickberger SA, Conti J, Daoud EG, Havranek E, Mehra MR, Piña IL, et al
. Patient selection for cardiac resynchronization therapy: From the Council on Clinical Cardiology Subcommittee on Electrocardiography and Arrhythmias and the Quality of Care and Outcomes Research Interdisciplinary Working Group, in collaboration with the Heart Rhythm Society. Circulation 2005;111:2146-50.
Bax JJ, Ansalone G, Breithardt OA, Derumeaux G, Leclercq C, Schalij MJ, et al.
Echocardiographic evaluation of cardiac resynchronization therapy: Ready for routine clinical use? A critical appraisal. J Am Coll Cardiol 2004;44:1-9.
Bax JJ, Bleeker GB, Marwick TH, Molhoek SG, Boersma E, Steendijk P, et al.
Left ventricular dyssynchrony predicts response and prognosis after cardiac resynchronization therapy. J Am Coll Cardiol 2004;44:1834-40.
Borleffs CJ, Ypenburg C, van Bommel RJ, Delgado V, van Erven L, Schalij MJ, et al.
Clinical importance of new-onset atrial fibrillation after cardiac resynchronization therapy. Heart Rhythm 2009;6:305-10.
Bristow MR, Feldman AM, Saxon LA. Heart failure management using implantable devices for ventricular resynchronization: Comparison of Medical Therapy, Pacing, and Defibrillation in Chronic Heart Failure (COMPANION) trial. COMPANION Steering Committee and COMPANION Clinical Investigators. J Card Fail 2000;6:276-85.
Bristow MR, Saxon LA, Boehmer J, Krueger S, Kass DA, De Marco T, et al.
Comparison of Medical Therapy, Pacing, and Defibrillation in Heart Failure (COMPANION) Investigators. Cardiac-resynchronization therapy with or without an implantable defibrillator in advanced chronic heart failure. N Engl J Med 2004;350:2140-50.
Fish JM, Di Diego JM, Nesterenko V, Antzelevitch C. Epicardial activation of left ventricular wall prolongs QT interval and transmural dispersion of repolarization: Implications for biventricular pacing. Circulation 2004;109:2136-42.
Guerra JM, Wu J, Miller JM, Groh WJ. Increase in ventricular tachycardia frequency after biventricular implantable cardioverter defibrillator upgrade. J Cardiovasc Electrophysiol 2003;14:1245-7.
Epstein AE, DiMarco JP, Ellenbogen KA, Estes NM, Freedman RA, Gettes LS, et al.
ACC/AHA/HRS 2008 guidelines for device-based therapy of cardiac rhythm abnormalities: Executive Summary A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the ACC/AHA/NASPE 2002 Guideline Update for Implantation of Cardiac Pacemakers and Antiarrhythmia Devices): Developed in Collaboration With the American Association for Thoracic Surgery and Society of Thoracic Surgeons. Circulation 2008;117:2820-40.
Saksena S. Implantable defibrillators in the third millennium: Increasingly relegated to a standby role? J Am Coll Cardiol 2000;36:828-31.
Garrigue S, Barold SS, Hocini M, Jaïs P, Haïssaguerre M, Clementy J. Treatment of drug refractory ventricular tachycardia by biventricular pacing. Pacing Clin Electrophysiol 2000;23:1700-2.
Higgins SL, Yong P, Sheck D, McDaniel M, Bollinger F, Vadecha M, et al.
Biventricular pacing diminishes the need for implantable cardioverter defibrillator therapy. Ventak CHF Investigators. J Am Coll Cardiol 2000;36:824-7.
Kowal RC, Wasmund SL, Smith ML, Sharma N, Carayannopoulos GN, Le B, et al.
Biventricular pacing reduces the induction of monomorphic ventricular tachycardia: A potential mechanism for arrhythmia suppression. Heart Rhythm 2004;1:295-300.
Mykytsey A, Maheshwari P, Dhar G, Razminia M, Zheutlin T, Wang T, et al
. Ventricular tachycardia induced by biventricular pacing in patient with severe ischemic cardiomyopathy. J Cardiovasc Electrophysiol 2005;16:655-8.
Stellbrink C, Auricchio A, Diem B, Breithardt OA, Kloss M, Schöndube FA, et al.
Potential benefit of biventricular pacing in patients with congestive heart failure and ventricular tachyarrhythmia. Am J Cardiol 1999;83:143D-50.
European Heart Rhythm Association, Heart Rhythm Society, Zipes DP, Camm AJ, Borggrefe M, Buxton AE, et al
. 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). J Am Coll Cardiol 2006;48:e247-346.
Bristow MR, Saxon LA, Boehmer J, Krueger S, Kass DA, De Marco T, et al.
Cardiac-resynchronization therapy with or without an implantable defibrillator in advanced chronic heart failure. N Engl J Med 2004;350:2140-50.
Lindenfeld J, Feldman AM, Saxon L, Boehmer J, Carson P, Ghali JK, et al.
Effects of cardiac resynchronization therapy with or without a defibrillator on survival and hospitalizations in patients with New York Heart Association class IV heart failure. Circulation 2007;115:204-12.
Mahdi Ramezani Binabaj
Students' Research Committee, Baqiyatallah University of Medical Science, Tehran, IR
Source of Support: None, Conflict of Interest: None
[Table 1], [Table 2]