Factors determining long-term outcomes and survival in patients with coronary artery disease and ventricular tachyarrhythmias: a single center experience

Effect of coronary revascularization on long-term clinical outcomes in patients with ischemic cardiomyopathy and recurrent ventricular arrhythmia

BACKGROUND

Patients with ventricular tachycardia (VT) postmyocardial infarction (MI) are a higher risk group with significant morbidity and mortality. We examined the impact of prior coronary revascularization on clinical outcomes in patients with ischemic cardiomyopathy and VT.

METHODS

The VANISH trial randomized 259 patients with prior MI and antiarrhythmic drug-refractory VT to receive escalated medical therapy or catheter ablation. Clinical outcomes were compared according to whether patients have undergone prior revascularization procedures. The primary outcome was a composite of death, appropriate implantable cardiac defibrillator (ICD) shock, or VT storm. The secondary outcomes included elements of the primary outcome, hospitalization, and any ventricular arrhythmia.

RESULTS

190 patients (73%) had prior coronary revascularization. Revascularization group had more men (97% vs 83%; P  =  0.0003) and patients in that group were older (mean age 69.3 ± 7.6 vs 66.7 ± 9.2; P  =  0.04), had more renal insufficiency (22.6% vs 8.7%; P  =  0.01), and were more likely to have an implanted cardiac resynchronization device (23% vs 10%, P  =  0.03) as compared with the nonrevascularized patients. There were no significant differences in baseline medication use. There was a trend toward fewer hospitalizations in the revascularization group (64% vs 77%; P  =  0.07); there were no differences in the individual outcomes of mortality, VT storm, ICD shocks, recurrent MI, or cardiac failure.

CONCLUSIONS

In this cohort of patients with an ischemic cause for VT, a history of prior coronary revascularization was not associated with a reduction in ventricular arrhythmia or mortality.

Malignant ventricular arrhythmias after off-pump coronary artery bypass

BACKGROUND/PURPOSE

Sustained ventricular tachycardia and ventricular fibrillation (VT/VF) are rare complications after coronary surgery. Off-pump coronary artery bypass (OPCAB) was developed to decrease postoperative complications. No studies to date have specifically addressed VT/VF after OPCAB. We sought to assess the incidence, risk factors, and outcome of VT/VF after OPCAB.

METHODS

The study included a retrospective review of 1010 patients undergoing OPCAB between 2000 and 2012. Data were compared between the VT/VF patients and control patients who were the first cases of OPCAB in each month during the study period and did not have VT/VF.

RESULTS

Twenty-three patients (2.3%) developed VT/VF after OPCAB. The hospital mortality rate was 17.4%. In univariate analysis, the risk factors for VT/VF were old age, rapid heart rate, prolonged corrected QT interval, severe congestive heart failure, poor left ventricular ejection fraction, large left ventricular end-diastolic diameter, chronic kidney disease, preoperative dialysis, low blood hemoglobin level, preoperative intubation, recent myocardial infarction, high European System for Cardiac Operative Risk Evaluation, urgent/emergent operation, use of intra-aortic balloon pump, conversion to on-pump beating heart, postoperative dialysis, and no use of beta-blockers after operation. Multivariate analysis identified preoperative corrected QT interval > 426 milliseconds [odds ratio (OR) = 4.501; 95% confidence interval (CI) = 1.153-17.570] and estimated glomerular filtration rate < 30 mL/minute/1.73 m(2) (OR = 4.876; 95% CI = 1.112-21.374) as independent risk factors.

CONCLUSION

Postoperative VT/VF was rare after OPCAB but was associated with high mortality. Prolonged corrected QT interval and chronic kidney disease were independent risk factors. Recognition of these risk factors, proper prevention, and early intervention may improve survival.

Predictors of electrical storm recurrences in patients with implantable cardioverter-defibrillators

AIMS

To determine prevalence and predictors of electrical storm recurrences (ES-Rs) in patients with implantable cardioverter-defibrillators (ICDs) as electrical storms (ESs) represent serious clinical events carrying a high risk of mortality.

METHODS AND RESULTS

Single-centre study analysing data of consecutive patients receiving an ICD between 1993 and 2008. Electrical storm was defined as ≥ 3 separate ventricular tachyarrhythmic (VT/VF) episodes ≤ 24 h. Nine hundred and fifty-five patients [mean left ventricular ejection fraction (LVEF) 35.7 ± 15.6%] were prospectively followed for 54.2 ± 35.5 months. In 274 of 955 patients (28.7%), 2871 VT/VF episodes were observed. One hundred and fifty-three ES episodes occurred in 63 of 955 patients (6.6%). Thirty-two of 63 patients (50.8%) experienced ≥ 2 ES episodes. Twenty-six of 32 patients (81.2%) with ES-Rs experienced the second ES episode within 1 year after the initial event. Cox regression analysis identified an LVEF ≤ 30% (OR 2.2; 95% CI 1.021-4.856; P = 0.044) and a patient's age >65 years (OR 3.5; 95% CI 1.207-10.176; P = 0.021) to be predictive for ES-Rs. Patients with angiotensin-converting enzyme (ACE) inhibitor therapy were less likely to experience ES-Rs (OR 0.39; 95% CI 0.187-0.817; P = 0.013).

CONCLUSIONS

Electrical storm events are not rare in a 'real-world' patient population with ICDs (6.6% in 4.5 years). The risk for ES-Rs, especially within the first year after the initial event, is high. Left ventricular ejection fraction ≤ 30%, age >65 years, and a lack of ACE inhibitor therapy are independent predictors of ES-R.

A correlative study comparing current different methods of calculating left ventricular ejection fraction

BACKGROUND

Left ventricular ejection fraction (EF) is a major determinant of survival in patients with coronary artery disease (CAD). Comparative accuracy of numerous modalities in calculating EF is not well investigated.

METHOD

We compared EF as calculated by rest and post-stress Cedars automated quantitative gated SPECT (AQGS), rest and post-stress semi-automatically processed gated SPECT (MQGS), echocardiography and contrast ventriculography (LVG) to those determined by rest and post-stress cavity-to-myocardium ratio (CMR) in 109 patients. Gated SPECT was performed based on a 2-day protocol using Tc-MIBI.

RESULTS

Mean EF in LVG, echo, post-stress CMR, rest CMR, post-stress AQGS, rest AQGS, post-stress MQGS and rest MQGS were 41.8%+/-12.1, 44.8%+/-11.8, 38.1%+/-10.7, 35.7%+/-12.1, 44.5%+/-15.1, 46.9%+/-14.7, 40.1%+/-14.3 and 43.5%+/-14.3 respectively. Although significant differences were observed between some of these methods, good and excellent linear correlations were present among values (all Pearson correlations >0.63). Considering LVG as the 'gold standard', we defined two groups: EF <35% (class 1) and >35% (class 2). Discriminant analysis showed that SPECT has the ability to predict patients' classes. In 4/18 of patients with normal SPECT (on both visual and quantitative analyses, SSS <4), EF on QGS showed a significant decrease on post-stress compared with rest.

CONCLUSION

There is a good correlation in calculating EF by LVG, QGS and echocardiography, regardless of EF value. Whenever QGS is impossible, CMR is a reliable indirect indicator of EF. Gating of both phases (and when impossible, CMR of both phases) has an additional value in diagnosis of CAD.

Prevention of sudden death in patients with coronary artery disease: do lipid-lowering drugs play a role?

Ventricular arrhythmias are the most common cause of sudden cardiac death in patients with coronary artery disease. Since treatment of hypercholesterolemia in patients with coronary artery disease reduces the risk of major coronary events by about 30%, one could speculate that this treatment could also result in a reduction of arrhythmic episodes in high-risk patients. In this review, the importance of myocardial ischemia as a trigger for ventricular arrhythmias, as well as the available data that suggest a possible effect of anti-ischemic treatments, including lipid-lowering drugs, on these arrhythmias are presented. Also, possible mechanisms and future research to test the hypothesis that lipid-lowering drugs can reduce life-threatening ventricular arrhythmias are discussed.

The implantable cardioverter-defibrillator: does everybody need one?

The implantable cardioverter-defibrillator (ICD) has emerged as an effective, but expensive, therapy for arrhythmic sudden cardiac death. ICD use has been increasing by 20% to 30% per year. Clinical trials have shown that the ICD can be effective for both the primary prevention and the secondary prevention of sudden cardiac death in selected populations. Despite the available trial evidence, several issues pertaining to ICD use remain unresolved, including the treatment of patients not represented in clinical trials, the optimal selection of patients who will benefit from an ICD, the duration of benefit from an ICD, the quality of life for patients with an ICD, and both the cost-effectiveness and the cost impact of the ICD. These considerations are discussed in this article.