The prevalence of permanent pacemaker implantation after open-heart surgeries; eight years of experience in Tehran heart center.

BACKGROUND: We aimed to evaluate the prevalence of permanent pacemaker implantation (PPI) among open-heart surgery patients. METHODS: We reviewed data from 23 461 patients undergoing open-heart surgeries between 2009 and 2016 in our heart center in Iran. A total of 18 070 patients (77%) had coronary artery bypass grafting (CABG), 3 598 (15.3%) valvular surgeries, and 1 793 (7.6%) congenital repair procedures. Finally, 125 patients who received PPI following open-heart surgeries were enrolled in our study. We defined the demographic and clinical characteristics of all these patients. RESULTS: PPI was required in 125 (0.53%) patients with an average age of 58 ± 15.3 years. The average hospitalization time after surgery and waiting time for PPI were 19.7 ± 10.2 and 11.4 ± 6.5 days, respectively. Atrial fibrillation was the dominant pre-operative cardiac conduction abnormality (29.6%). Also, the primary indication for PPI was complete heart block in 72 patients (57.6%). Patients in the CABG group were significantly older (P = 0.002) and were more likely to be male (P = 0.030). The valvular group longer bypass and cross-clamp times and had more left atrial abnormalities. In addition, the congenital defect group was younger and had longer ICU stay times. CONCLUSIONS: Based on our study findings, PPI was required in 0.53% of patients following open-heart surgery due to damage to the cardiac conduction system. The current study paves the way for future investigations to identify possible predictors of PPI in patients undergoing open-heart surgeries.

Detection of myocardial injury due to defibrillation threshold checking after insertion of implantable cardioverter/defibrillators.

AIMS: Possible myocardial damage caused by defibrillation threshold (DFT) control and its extent after insertion of implantable cardioverter/defibrillators (ICD) is still a matter for debate. This study aimed to identify the effect of DFT checking during ICD implantation, compared with permanent pacemaker (PPM) implantation, on the magnitude of myocardial damage as assessed by cardiac troponin-T (cTNT) and CK-MB. METHODS AND RESULTS: A total of 133 candidates for ICD implantation were enrolled in the ICD group (mean age 60.66 +/- 12.25 years; males 111 [83.5%]) as well as 130 candidates in the PPM group (mean age 69.56 +/- 12.86 years; males 64 [49.2%]). DFT was controlled in all of the ICD patients. Serum levels of cTNT and CK-MB were measured at baseline plus 8 and 24 hours following the procedure. The results were adjusted for age, gender, and other confounding factors. The amount of cTNT rise after 8 and 24 hours in the ICD group was significantly higher than in the PPM group (p < 0.001 for both). These differences remained significant after adjustment for confounding factors. The level of CK-MB rise after 8 and 24 hours was also significantly higher in the ICD group, although it lost its significance after adjustment for age, gender and other confounding variables. There was no significant relationship between the amount of energy delivered and enzyme elevation. CONCLUSION: Elevation of cTNT and CK-MB after the ICD implantation was significantly higher than that after the PPM implantation and may be attributed to the DFT testing shock and resulting myocardial injury.

Coronary artery mycotic aneurysm in a patient suffering from subacute endocarditis: a case report and literature review.

Although mycotic aneurysm is a known and important disease in the cerebrovascular system, especially the brain, there are scarce reports about coronary artery mycotic aneurysms (CAMA). CAMA can occur not only in the context of endocarditis but also as a rare adverse event of coronary artery stenting, which has been used more extensively in recent years. Accordingly, it is essential to pay greater attention to its associated presentations and clinical course. Considering the scant evidence available, reporting the disease course of each patient with CAMA can help increase the physician's knowledge about this condition, which is why we are reporting this case. A 42-year-old man with diabetes was referred to our center with embolic left cerebellar infarction 3 months earlier, as well as a 2-month history of feverishness before his referral. His blood culture was positive for Viridans Streptococci, and he had paraclinical signs of inflammation and two- and three-dimensional transthoracic and transesophageal echocardiography (2D & 3D TTE and TEE) signs of aortic and mitral valves' infective endocarditis with the destruction of the aortic valve, severe aortic and mitral regurgitation, severe pulmonary hypertension, and moderate biventricular systolic dysfunction. Regarding the obviously dilated left main coronary artery on TEE images, contrast-enhanced chest multidetector computed tomography was performed for better assessment of coronary arteries with suspicion of CAMA, which confirmed aneurysmal dilatation of the proximal left main coronary artery. The presence of bacteria was confirmed on staining the valvular tissue, resected during the surgical replacement of aortic and mitral valves. As the cardiac surgeon considered CAMA resection and coronary bypass grafting high risk for the patient, he received parenteral antibiotic therapy, for 6 weeks. At 1-year follow-up, he was doing well with no signs/symptoms of endocarditis and well-functioning mechanical prosthetic valves. This case shows the significance of considering CAMA in the setting of endocarditis, resistant to medical and/or surgical therapy or in patients with coronary aneurysm, simultaneous with active endocarditis. Therefore, more attention should be paid to this extravalvular complication of endocarditis, and its possibility should be considered and investigated in any patient presented with valvular endocarditis, especially involving the aortic valve.

Predictors of mortality and clinical outcomes following implantable cardioverter-defibrillator therapy in elderly patients: A retrospective single-center cohort study.

Background and aims: Implantable cardioverter-defibrillators (ICDs) are frequently used to prevent sudden cardiac death in patients with high-risk arrhythmias. However, the use of ICD therapy in elderly patients beyond the predicted age of life expectancy is still controversial. We aimed to evaluate the predictors of mortality and clinical outcomes following ICD implantation in elderly patients. Methods: We conducted a retrospective analysis of 145 elderly patients aged 72 years and older who received ICD implantation between January 2010 and August 2015. We collected and analyzed baseline data, including clinical, demographic, and medical history, the reason for ICD therapy, procedural data, and echocardiography results. Follow-up data included the development of complications and mortality. The predictors of mortality were identified using the univariate and multivariable Cox regression models. Results: During the median follow-up duration of 30.5 [18.0-48.0] months, 141 cases completed follow-up (mean age = 76.0 ± 3.7 years). Forty-four patients experienced at least one episode of ICD therapy. Inappropriate shock, recurrent shock, and device-related infection were the most frequent complications observed in our study. Of the 145 patients, 42 died during the follow-up period, with an average survival time of 22.4 months after ICD implantation. Among these patients, 11 received ICD for primary prevention, and 31 received it for secondary prevention. Cardiovascular problems were the leading cause of death. We found that a low baseline ejection fraction (EF) was an independent predictor of mortality (hazard ratio = 0.93, 95% confidence interval: 0.90-0.98; p = 0.008). Conclusion: Our study suggests that ICD therapy is a valuable treatment option for elderly patients beyond their predicted age of life expectancy. The study highlights the importance of baseline EF as a significant predictor of mortality in these patients.

Repositioning a Displaced Right Ventricular Pacing Lead via Percutaneous Approach in Three Patients.

Lead-related complications compose a noticeable share of device-related complications. Pacemaker lead perforation is a recognized complication of lead implantation, particularly with active fixation leads, and should be considered in postoperative lead malfunction cases. We herewith present 3 challenging cases with ventricular pacemaker lead dispositioning who were successfully treated via percutaneous access.

The association between coronary arterial dominancy and extent of coronary artery disease in angiography and paraclinical studies.

The association between coronary arterial dominance patterns and the coronary artery diameter, length, and valvular heart diseases were previously studied. However, its association with coronary artery disease (CAD) is unclear. We investigated to determine whether the extent and localization of CAD differ in right, left, or codominant coronary arterial patterns. Twelve thousand five hundred fifty-eight patients admitted to Tehran Heart Center for coronary angiography were studied retrospectively (2004-2006). The extent and localization of CAD and the dominant artery were determined. There were 62.7% males. The mean age was 57.6 +/- 10.3. 84.2% [95% confidence interval (CI); 83.6-84.8%], 10.9% (95% CI; 10.4-11.4%), and 4.8% (95% CI; 4.4-5.2%) of the patients were right, left, and codominant, respectively; No significant difference considering age, sex, positive family history, hypertension, hyperlipidemia, electrocardiography, exercise treadmill stress test, and perfusion scan were seen in the groups. The right-dominant patients tend to have three-vessel disease (33.1% vs. 27%, P < 0.0001), stenosis of more than 50% in right coronary artery (65.9% vs. 57.9%, P < 0.0001) and left circumflex territories (64% vs. 59.4%, P = 0.01), more than the left-dominant patients. The involvements of the left main coronary artery, left anterior descending artery territory, and posterior descending artery were not significantly different. This study demonstrates a relationship between angiographic CAD severity, and the involved arterial territory and dominancy patterns.

Multiple multisite low-temperature and low-power radiofrequency currents for the induction of atrioventricular nodal reentry tachycardia in non-inducible patients.

AIMS: Some patients with documented episodes of paroxysmal supraventricular tachycardia (PSVT) do not have inducible tachycardia during the electrophysiological study. In this study, we describe how multiple low-temperature, low-power radiofrequency (RF) currents in the atrioventricular (AV) junction region can increase the rate of the induction of atrioventricular nodal reentrant tachycardia (AVNRT) in non-inducible cases. METHOD: We enrolled 31 consecutive patients (mean age = 50.9 ± 11.9 years; 5 [16.1 %] male) who presented with documented clinical PSVT in superficial electrocardiography but had non-inducible arrhythmia in the electrophysiology laboratory despite applying different stimulation protocols. We delivered low-power (25 W), low-temperature (45 °C) RF currents into the AV junction region to induce AVNRT. RESULTS: Arrhythmia was induced in 20 (64.5 %) patients, and it was non-sustained in 3 (9.6 %) patients. RF current was delivered into the posterior region near the coronary sinus ostium and midseptal region. RF ablation target in inducible patients was the non-inducibility of the AVNRT at the end of the procedure, while the target in the non-inducible patients was slow pathway ablation with no antegrade conduction over the slow pathway. During the follow-up period, none of the patients (either with inducible or non-inducible arrhythmia) had recurrence of AVNRT. CONCLUSION: Multiple low-power, low-temperature RF current application into the AV junction region is a more effective method for the induction of AVNRT in comparison with a single current use into the slow pathway.

Age and the Head-Up Tilt Test Outcome in Syncope Patients.

BACKGROUND: The head-up tilt test (HUTT) is a useful diagnostic tool for syncope. OBJECTIVES: We sought to investigate the outcome of the HUTT in syncope patients and identify the relationship between age and different hemodynamic outcomes. PATIENTS AND METHODS: In this cross-sectional study, we prospectively enrolled consecutive patients who presented with syncope and underwent the HUTT with a clinical suspicion of neurocardiogenic syncope after the exclusion of orthostatic hypotension cases. The HUTT consisted of consecutive passive and active phases. In the passive phase, the patients were tilted at 70 degrees for 20 minutes; and if negative, the test was repeated with 400 micrograms of sublingual nitroglycerin for another 20 minutes. Positive responses were classified according to the classification of the vasovagal syncope international study (VASIS) and compared for age and gender. RESULTS: A total of 498 patients were enrolled (age = 44.93 ± 18.77 years; male = 271 [54.4%]). Overall, 291 (58.4%) patients had a positive HUTT, while 256 (88.5%) patients had a positive result during the active phase. The test results were as follows: 107 (36.7%) mixed type (VASIS I), 103 (35.3%) cardioinhibitory (VASIS IIA = 44 [15.1%]; VASIS IIB = 59 [20.2%]), and 80 (27.4%) vasodepressive (VASIS III). There was no relationship between gender and syncope type. The trend of the HUTT result significantly changed with age, and the rate of cardioinhibitory syncope decreased after middle ages (P value for trend = 0.02). CONCLUSIONS: Hemodynamic response to the HUTT was associated with age. Cardioinhibitory response became less frequent with age due to exaggerated vagal activity in the younger patients as compared with the older subjects.

Generator and lead-related complications of implantable cardioverter defibrillators.

BACKGROUND: Increase in the number of patients treated with Implantable Cardioverter Defibrillator (ICD) requests more attention regarding its complications. OBJECTIVES: This study aimed to assess the generator- and lead-related complications at implantation and during follow-up in the patients who were treated with ICD for primary and secondary prevention reasons. METHODS: We retrospectively reviewed 255 consecutive patients who underwent transvenous ICD implantation for the first time in a 7-year period and were followed-up for 3 years at Tehran Heart Center. The personal and clinical data of the patients as well as specific data on the ICD implantation were retrieved. The frequency of each of the complications was reported and the study variables were compared between the patients with and without complications using Student's t-test and chi-square test where appropriate. P values less than 0.05 were considered as statistically significant. RESULTS: Out of a total of 525 implanted leads and 255 implanted devices in 255 patients (mean age = 62.57 ± 13.50 years; male = 196 [76.9%]), complications leading to generator or lead replacement occurred in 32 patients (12.5%). The results revealed no significant difference between the patients with and without complications regarding gender and age (P = 0.206 and P = 0.824, respectively). Also, no significant difference was found between the two groups concerning the ejection fraction (P = 0.271). Lead fracture was the most frequent lead-related complication and was observed in 17 patients (6.6%). Besides, it was mainly observed in the RV leads. Generator-related complications leading to generator replacement were observed in 2 patients (0.7%). CONCLUSIONS: Despite considerable improvements in the ICD technology, the rate of the ICD complications leading to device replacement and surgical revision, especially those related to the leads, is still clinically important.

Left ventricular lead placement with over-the-wire technique for right ventricular pacing in a patient with distorted vessels.

Vascular access can present a clinical challenge in the implantation of permanent pacemaker leads. We describe the case of an 81-year-old man with complete heart block in whom it was difficult to find a suitable vein for advancing a pacemaker lead. The left cephalic vein was selected for lead implantation; however, because of a 90° angle between the cephalic and axillary veins, the lead failed to advance. Because the patient was elderly and at high risk, we decided to place a left ventricular pacing lead in the right ventricle by means of an over-the-wire technique. After 1 month, the patient's pacing threshold was good, and the lead remained in the right ventricular apex. When patients have distorted vessels and lead placement seems difficult or impossible, we think that the over-the-wire placement technique can be effective.

Implantation of transvenous permanent pacemaker in a patient with persistent left superior vena cava and absent right superior vena cava.

Vascular access has remained a major challenge for implantation of permanent pacemaker leads. A persistent Left Superior Vena Cava (LSVC), especially with an absent Right Superior Vena Cava (RSVC), is a rare finding during pacemaker implantation and is accompanied by technical difficulties. Herein, we describe a case of sinoatrial node arrest, in which finding a suitable vein for passing the lead was challenging. The patient had a persistent LSVC with an absent RSVC.

Posteroseptal accessory pathway in association with coronary sinus diverticulum: electrocardiographic description and result of catheter ablation.

AIMS: A precise knowledge of the coronary sinus (CS) anatomy and its potential anomalies seems essential to increase the rate of success in patients with a prior history of multiple ablation failures of the posteroseptal accessory pathway or in whom this procedure cannot be performed easily. We aimed to describe the anatomic and electrocardiographic characteristics of the CS diverticulum in association with the posteroseptal accessory pathway and subsequent catheter ablation results. METHODS: We retrospectively recruited 12 patients with posteroseptal accessory pathways associated with CS diverticula from patients referred to Tehran Heart Center for electrophysiological study and ablation between January 2004 and December 2011. RESULTS: The study population consisted of eight males and four females at a mean age of 48.2 ± 17.5 years with posteroseptal accessory pathways. The most frequent initial presentation was orthodromic atrioventricular re-entrant tachycardia and atrial fibrillation. The rate of acute success for radiofrequency ablation and the recurrence rate were 75 and 16.6 %, respectively. Larger diverticula tended to have more failure and recurrence rate, albeit not significant. None of the patient's characteristics could significantly predict the success of the ablation. CONCLUSION: Our total initial failure rate and subsequent recurrence was around 41 %. Better results might have been achieved had we applied irrigated tip catheters or NavX(TM)-guided cryoablation or subxiphoid epicardial mapping and ablation.

Coronary anatomy characteristics in patients with isolated right bundle branch block versus subjects with normal surface electrocardiogram.

INTRODUCTION AND OBJECTIVE: Isolated right bundle branch block is a common finding in the general population. It may be associated with variations in detailed coronary anatomy characteristics. The aim of this study was to investigate the coronary anatomy in patients with isolated right bundle branch block and to compare that with normal individuals. METHOD: In this case-control study we investigated the coronary anatomy by reviewing angiographic films in two groups of normal coronary artery patients: patients with right bundle branch block (RBBB) (n = 92) and those with normal electrocardiograms (n = 184). RESULTS: There was no significant difference between the two groups in terms of diminutive left anterior descending artery, dominancy, number of obtuse marginal artery, diagonal, acute marginal artery, the position of the first septal versus diagonal branch, presence of ramus artery, and size of left main artery. The number of septal branches was higher in the case group (p-value <0.001). Origination of the atrioventricular node artery from the right circulatory system was more common in both groups but cases showed more tendency to follow this pattern (p-value = 0.021). The frequency of the normal conus branch was higher in the cases versus controls (p-value = 0.009). CONCLUSIONS: Coronary anatomy characteristics are somewhat different in subjects with RBBB compared to normal individuals.

Prosthetic tricuspid valve thrombosis: three case reports and literature review.

A common complication of prosthetic heart valves is thrombosis. Although the incidence of prosthetic valve thrombosis (PVT) in the tricuspid position is high, there are not enough data on the management of it, in contrast to left-sided PVT. Here, we describe three cases of tricuspid PVT with three different management approaches: thrombolytic therapy; close observation with oral anticoagulants; and surgery. The first case was a woman who suffered from recurrent PVT, for which we successfully used Tenecteplase for second and third episodes. We employed Tenecteplase in this case for the first time in the therapy of tricuspid PVT. The second case had fixed leaflets in open position while being symptomless. At six months' follow-up, with the patient having taken oral anticoagulants, the motion of the leaflets was restricted and she was symptomfree. The last case was a woman who had a large thrombus in the right atrium immediately after mitral and tricuspid valvular replacement. The patient underwent re-replacement surgery and a new biological valve was implanted in the tricuspid position. Also, we review the literature on the pathology, signs and symptoms, diagnosis, and management of tricuspid PVT.

Anatomy of Atrioventricular Node Artery and Pattern of Dominancy in Normal Coronary Subject: A Comparison between Individuals with and without Isolated Right Bundle Branch Block.

BACKGROUND: Isolated right bundle branch block (RBBB) is a common finding in the general population. The atrioventricular node (AVN) artery contributes to the blood supply of the right bundle branch. Our hypothesis was that the anatomy of the AVN artery and the pattern of dominancy differ between subjects with and without RBBB. METHODS: We retrospectively studied the coronary angiography of 92 patients with RBBB and 184 age- and gender-matched controls without RBBB. All the subjects had angiographically proven normal coronary arteries. The dominant circulation and precise origin of the AVN artery were determined in each subject. Obtained data were compared between the two study groups. RESULTS: There was no significant difference between the two groups in terms of dominancy (p value = 0.200). Origination of the AVN artery from the right circulatory system was more common in both groups, but this pattern was more prevalent in the cases than in the controls (p value = 0.021). There was a great variation of the AVN artery origin. In the total study population, the AVN artery was more commonly separated from a non crux origin than from the crux area. The prevalence of the non-crux origination of the AVN artery was significantly higher in the cases than in the controls (p value < 0.001). While the origination of the AVN artery from the right circulatory system was more common in both groups, the prevalence of the right origin of the AVN artery was significantly higher in the cases than in the controls. We observed that the AVN artery most commonly originated from the dominant artery but not necessarily from the crux. CONCLUSION: The anatomy of the AVN artery but not the pattern of dominancy is somewhat different in subjects with RBBB compared with normal individuals.

Glomerular filtration rate is related to severity of obstructive coronary artery disease in patients undergoing coronary angiography.

PURPOSE: Chronic kidney disease is independently associated with an increased risk of cardiovascular events; however, the relationship between the glomerular filtration rate (GFR) and coronary artery disease (CAD) in patients undergoing coronary angiography has yet to be fully elucidated. METHODS: This retrospective study enrolled a total of 7968 patients who underwent diagnostic coronary artery catheterization [mean age = 54.8 ± 10.6 years, 74.4% males] and did not have any previous history of coronary revascularization, diabetes mellitus, hypertension, end-stage renal disease treated by dialysis or renal transplantation, and were not taking diuretics or drugs acting on renin angiotensin system. The severity of CAD was defined as the number of coronary arteries with a luminal stenosis ≥50% on the angiogram, and the GFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI). RESULTS: There were 2133 (26.8%) patients with GFR ≥ 90 ml/min/1.73 m(2), 4574 (57.4%) patients with 60 ≤ GFR < 90 ml/min/1.73 m(2), 1073 (13.5%) with 45 ≤ GFR < 60 ml/min/1.73 m(2) and 181 (2.3%) with 15 < GFR < 45 ml/min/1.73 m(2). After adjustment for traditional cardiovascular risk factors (age, sex, dyslipidemia, low to high-density lipoprotein ratio, smoking status, and family history), the GFR showed a significant association with the severity of CAD and remained a significant predictor of CAD (Odds Ratio raised from 1.1 in patients with 60 ≤ GFR < 90 ml/min/1.73 m(2) to 1.8 in patients with 15 < GFR < 45 ml/min/1.73 m(2)). CONCLUSIONS: A reduced kidney function, even mildly, is significantly associated with CAD severity, independently of other traditional CAD risk factors.

Characterization of suitability of coronary venous anatomy for targeting left ventricular lead placement in patients undergoing cardiac resynchronization therapy.

BACKGROUND: Differences in the quantity and distribution of coronary veins between patients with ischemic and nonischemic cardiomyopathy might affect the potential for the left ventricular (LV) lead targeting in patients undergoing cardiac resynchronization therapy (CRT). In the current study, we assessed and compared the suitability of the coronary venous system for the LV lead placement in ischemic and dilated cardiomyopathy. METHODS: This single-centre study, performed at our hospital, retrospectively studied 173 patients with the New York Heart Association class III or IV who underwent CRT. The study population was comprised of 74 patients with an ischemic underlying etiology and 99 patients with a non-ischemic etiology. The distribution of the veins as well as the final lead positions was recorded. RESULTS: There was no significant difference between the two groups in terms of the position of the available suitable vein with the exception of the posterior position, where the ischemic group had slightly more suitable veins than did the dilated group (48.4% versus 32.1%, p value = 0.049). There was also no significant difference with respect to the final vein, through which the LV lead was inserted. Comparative analysis showed that the patients with previous coronary artery bypass grafting surgery (CABG) had significantly fewer suitable veins in the posterolateral position than did the non-CABG group (16.3% versus 38.7%, p value = 0.029). There was, however, no significant difference between the two subgroups regarding the final vein position in which the leads were inserted. CONCLUSION: The final coronary vein position suitable and selected for the LV lead insertion was not different between the cases with cardiomyopathy with different etiologies, and nor was it different between the ischemic cases with and without a history of CABG. Patients with a history of procedures around the coronary vessel may have an intact or recovered venous system and may, therefore, benefit from transvenous LV lead placement for CRT.

Atrial standstill: a rare case.

We introduce a 32-year-old man who was evaluated for a dizziness and headache of unknown origin for at least two months and was referred to our center after ECG findings. He was finally diagnosed as a case of idiopathic, familial, diffuse, persistent atrial standstill, which is a rare arrhythmogenic condition characterized by the absence of electrical and mechanical activity in the atria. He successfully received a single-chamber permanent pacemaker.

Effect of exercise-based cardiac rehabilitation following coronary artery bypass surgery on ventricular repolarization indices.

PURPOSE: Indices of ventricular repolarization heterogeneity are associated with future arrhythmias and sudden cardiac death. We investigated the effect of exercise-based cardiac rehabilitation (CR) on these indices in a sample of Iranian patients. METHODS: Patients (N 122), who had undergone coronary artery bypass surgery (CABGS), were enrolled in this cohort study. Sixty patients attended 15 or more sessions of CR (CR group) and the remaining 62 patients attended 5 or fewer sessions of CR (control group). A standard 12-lead electrocardiogram was recorded for each patient. QT interval dispersion (QTd), RR interval variability (RRV), and heart rate-corrected QTd (QTc-d) were measured 3 times as follow: just before surgery, at the beginning of the first session of the CR program, and at the end of the 15th session for the CR group or the last session for the control group. RESULTS: Following completion of the exercise-training program, the CR group showed a significant decrease in QTd (Δ = -49.4%, P < .0001) and QTc-d (Δ = 52.8%, P .0001), but not in the control group (Δ = 13.4% and 17.9%, respectively, P > .05 for both). In both groups, no statistically significant change in RRV was observed. After adjustment for variables such as age, gender, digoxin use, ß-blocker use, and prerehabilitation ejection fraction, CR remained the independent predictor of QTd and QTc-d. CONCLUSION: Results suggest that cardiac rehabilitation and exercise training programs significantly improve the indices of ventricular repolarization heterogeneity in patients with coronary artery disease who received CABGS.