When to consider an implantable cardioverter defibrillator following myocardial infarction?

After reading this article the reader should be familiar with: Current guidelines for implantable cardioverter defibrillator (ICD) use post myocardial infarction (MI) and ischaemic cardiomyopathy. Primary prevention ICD guidelines. Secondary prevention ICD guidelines. Non-sustained ventricular tachycardia in patients post MI and the use of ICDs. Programming ICDs.

Effect of warfarin on survival in patients with concomitant left ventricular systolic dysfunction and pulmonary hypertension: a population cohort study.

BACKGROUND: The use of oral anticoagulation in patients with heart failure in sinus rhythm remains controversial as previous large randomized controlled trials (RCTs) have not shown a survival benefit. However, heterogeneity exists among heart failure patients and it is possible that high-risk subgroups may benefit from anticoagulation (warfarin). We hypothesize that one such subgroup are patients with heart failure and pulmonary hypertension (PH), conditions associated with coagulation abnormalities. METHODS: We conducted a retrospective, population-based, longitudinal cohort study in patients with left ventricular systolic dysfunction (LVSD) and PH [defined as a right ventricular systolic pressure (RVSP) >35 mmHg] identified from echocardiograms performed between January 1994 to May 2011. This data was linked using a unique patient-specific identifier to community-dispensed prescriptions, hospital admissions, and mortality data. For comparison, we included patients with LVSD and no PH. RESULTS: A total of 2619 subjects with LVSD and a measurable RVSP were identified (mean ± SD age of 73 ± 12 years); 1606 out of 2619 had PH and 1013 out of 2619 had no PH. The overall mean follow-up period was 2.56 ± 3.0 years. In patients with LVSD and PH, the use of warfarin was associated with an improved survival [hazard ratio (HR) = 0.72 95% confidence interval (CI) 0.58-0.90, P = 0.0003], fewer non-cardiovascular disease-related deaths (HR = 0.65, 95%CI 0.49-0.87, P = 0.0033 and showed a trend towards reduced cardiovascular disease-associated mortality (HR = 0.72, 95%CI 0.51-1.02). Warfarin did not improve survival in those with LVSD with no PH. CONCLUSIONS: In patients with both LVSD and PH, the use of warfarin is associated with a 28% reduction in mortality. Further prospective trials are required to confirm our findings.

Allopurinol reduces left ventricular mass in patients with type 2 diabetes and left ventricular hypertrophy.

OBJECTIVES: This study sought to ascertain whether high-dose allopurinol causes regression of left ventricular mass (LVM) in patients with type 2 diabetes mellitus (T2DM). BACKGROUND: Left ventricular hypertrophy (LVH) is common in T2DM and contributes to patients' high cardiovascular (CV) event rate. Oxidative stress (OS) has been implicated in LVH development, and allopurinol has been previously shown to reduce vascular OS. We therefore investigated whether allopurinol causes regression of LVH in patients with T2DM. METHODS: We conducted a randomized, double-blind, placebo-controlled study of 66 optimally-treated T2DM patients with echocardiographic evidence of LVH. Allopurinol, 600 mg/day, or placebo was given over the study period of 9 months. The primary outcome was reduction in LVM as calculated by cardiac magnetic resonance imaging at baseline and at 9 months' follow-up. Secondary endpoints were change in flow-mediated dilation and augmentation index. RESULTS: Allopurinol significantly reduced absolute LVM (-2.65 ± 5.91 g vs. placebo group +1.21 ± 5.10 g [p = 0.012]) and LVM indexed to body surface area (-1.32 ± 2.84 g/m(2) vs. placebo group +0.65 ± 3.07 g/m(2) [p = 0.017]). No significant changes were seen in either flow-mediated dilation or augmentation index. CONCLUSIONS: Allopurinol causes regression of LVM in patients with T2DM and LVH. Regression of LVH has been shown previously to improve CV mortality and morbidity. Therefore, allopurinol therapy may become useful to reduce CV events in T2DM patients with LVH. (Allopurinol in Patients with Diabetes and LVH; UKCRN 8766).

High-dose allopurinol reduces left ventricular mass in patients with ischemic heart disease.

OBJECTIVES: This study sought to ascertain if high-dose allopurinol regresses left ventricular mass (LVM) in patients with ischemic heart disease (IHD). BACKGROUND: LV hypertrophy (LVH) is common in patients with IHD including normotensive patients. Allopurinol, a xanthine oxidase inhibitor, has been shown to reduce LV afterload in IHD and may therefore also regress LVH. METHODS: A randomized, double-blind, placebo-controlled, parallel group study was conducted in 66 patients with IHD and LVH, comparing 600 mg/day allopurinol versus placebo therapy for 9 months. The primary outcome measure was change in LVM, assessed by cardiac magnetic resonance imaging (CMR). Secondary outcome measures were changes in LV volumes by CMR, changes in endothelial function by flow-mediated dilation (FMD), and arterial stiffness by applanation tonometry. RESULTS: Compared to placebo, allopurinol significantly reduced LVM (allopurinol -5.2 ± 5.8 g vs. placebo -1.3 ± 4.48 g; p = 0.007) and LVM index (LVMI) (allopurinol -2.2 ± 2.78 g/m(2) vs. placebo -0.53 ± 2.5 g/m(2); p = 0.023). The absolute mean difference between groups for change in LVM and LVMI was -3.89 g (95% confidence interval: -1.1 to -6.7) and -1.67 g/m(2) (95% confidence interval: -0.23 to -3.1), respectively. Allopurinol also reduced LV end-systolic volume (allopurinol -2.81 ± 7.8 mls vs. placebo +1.3 ± 7.22 mls; p = 0.047), improved FMD (allopurinol +0.82 ± 1.8% vs. placebo -0.69 ± 2.8%; p = 0.017) and augmentation index (allopurinol -2.8 ± 5.1% vs. placebo +0.9 ± 7%; p = 0.02). CONCLUSIONS: High-dose allopurinol regresses LVH, reduces LV end-systolic volume, and improves endothelial function in patients with IHD and LVH. This raises the possibility that allopurinol might reduce future cardiovascular events and mortality in these patients. (Does a Drug Allopurinol Reduce Heart Muscle Mass and Improve Blood Vessel Function in Patients With Normal Blood Pressure and Stable Angina?; ISRCTN73579730).

Pulmonary hypertension predicts all-cause mortality in patients with heart failure: a retrospective cohort study.

AIMS: The presence of pulmonary hypertension (PH) in left ventricular systolic dysfunction (LVSD) and symptomatic heart failure is an ominous sign. There are insufficient data regarding the risk conferred by increasing severity of PH in patients with heart failure. METHODS AND RESULTS: We performed a record linkage study in Tayside, Scotland (population ∼400,000) utilizing the Tayside echocardiogram database (>50,000 echocardiograms) maintained by the Health Informatics Centre (HIC). Data sets from the HIC include mortality data, cardiovascular medications, and other healthcare activities linked anonymously by the community health index (CHI) number. Patients were included in the analysis if they had LVSD, had a valid right ventricular systolic pressure (RVSP) measurement, and had a loop diuretic prescription (provided not more than 1 year prior to echocardiogram). A Cox proportional hazard model was used to examine the effects of RVSP on all-cause mortality. A total of 1612 patients [mean age, 75.2 ± 10.9 (SD) years; 57.4% male] met the entry criteria. Mean RVSP for the cohort was 44.9 ± 13.1 mmHg and mean follow-up was 2.8 ± 2.5 years. For each 5 mmHg stepwise increase in RVSP, after adjustment for confounding factors including the degree of LVSD and the presence of chronic obstructive pulmonary disease, the hazard ratio (HR) for all-cause mortality was 1.06 (1.03-1.08, P < 0.001). CONCLUSIONS: Pulmonary hypertension predicted all-cause mortality in a heterogeneous group of patients with heart failure. Each 5 mmHg rise in RVSP was associated with a 6% increased risk of death.

The impact of renin-angiotensin-aldosterone system blockade on heart failure outcomes and mortality in patients identified to have aortic regurgitation: a large population cohort study.

OBJECTIVES: The aim of this study was to investigate the effect of renin-angiotensin system blockade on outcomes in patients with aortic regurgitation (AR). BACKGROUND: Angiotensin-converting enzyme (ACE) inhibitors have the potential to reduce afterload, blunt left ventricular wall stress, and limit left ventricular dilation and hypertrophy. However, long-term studies have yielded inconsistent results, and very few have assessed clinical outcomes. METHODS: The Health Informatics Centre dispensed prescription and morbidity and mortality database for the population of Tayside, Scotland, was linked through a unique patient identifier to the Tayside echocardiography database. Patients diagnosed with at least moderate AR from 1993 to 2008 were identified. Cox regression analysis was used to assess differences in all-cause mortality and cardiovascular (CV) and AR events (heart failure hospitalizations, heart failure deaths, or aortic valve replacement) between those treated with and without ACE inhibitors or angiotensin receptor blockers (ARBs). RESULTS: A total of 2,266 subjects with AR (median age 74 years; interquartile range: 64 to 81 years) were studied, with a mean follow-up period of 4.4 ± 3.7 years. Seven hundred and five patients (31%) received ACE inhibitor or ARB therapy. There were 582 all-cause deaths (25.7%). Patients treated with ACE inhibitors or ARBs had significantly lower all-cause mortality and fewer CV and AR events, with adjusted hazard ratios of 0.56 (95% confidence interval [CI]: 0.64 to 0.89; p < 0.01) for all-cause mortality, 0.77 (95% CI: 0.67 to 0.89; p < 0.01) for CV events, and 0.68 (95% CI: 0.54 to 0.87; p < 0.01) for AR events. CONCLUSIONS: This large retrospective study shows that the prescription of ACE inhibitors or ARBs in patients with moderate to severe AR was associated with significantly reduced all-cause mortality and CV and AR events. These data need to be confirmed by a prospective randomized controlled outcome trial.

Meta-analysis of B-type natriuretic peptide's ability to identify stress induced myocardial ischemia.

Studies in victims of sudden cardiac death and those surviving a cardiac arrest have confirmed that extent of coronary artery disease is similar in those with and without angina, suggesting that it is the presence of myocardial ischemia rather than associated symptoms that determine the prognosis. Experimental models show that hypoxic myocardial tissue results in production of extra B-type natriuretic peptide (BNP), suggesting that BNP could potentially serve as a biomarker of myocardial ischemia. We performed a meta-analysis of the studies that link BNP to inducible myocardial ischemia as indicated by noninvasive stress tests. Values of true positive, false positive, true negative, and false negative were calculated from the reported sensitivity, specificity, disease prevalence, and total number of patients studied. Sixteen studies reporting data on 2,784 patients across 14 study populations were included in the final analysis. Mean age of participants was 55 to 69 years and 55% to 90% were men. Pooled sensitivity and specificity of BNP for detection of stress-induced myocardial ischemia were 71% (95% confidence interval [CI] 68 to 74) and 52% (95% CI 52 to 54), respectively. Pooled diagnostic odds ratio was 3.5 (95% CI 2.46 to 5.04) and summary receiver operating characteristic curve revealed an area under the curve of 0.71 ± 0.02 (mean ± SE). In conclusion, this meta-analysis suggests that an increased BNP level can identify inducible ischemia as detected by standard noninvasive stress tests. This raises the possibility of a whole new role for BNP in the diagnosis and management of myocardial ischemia.

Vitamin D and cardiovascular prevention.

Vitamin D has been known to medical science for almost a century. Yet, it is only in the last 15 years that we have realized that the biological effects of vitamin D extend far beyond the control of calcium metabolism. Recent observational evidence suggests strong links between low vitamin D levels and a range of cardiovascular conditions, including stroke, myocardial infarction, hypertension, and diabetes. Interventional studies are beginning to explore whether vitamin D supplementation can modify vascular health and prevent cardiovascular disease. This article reviews the physiology and function of vitamin D, examines the current observational and intervention data in cardiovascular disease, and discusses future research and current practice recommendations.