Carvedilol administration in acute myocardial infarction results in stronger inhibition of early markers of left ventricular remodeling than metoprolol

Background

The structural secuelae of acute myocardial infarction (AMI) is mostly dictated by left ventricular (LV) remodelling, leading to heart failure. Monocyte chemoattractant protein-1 (MCP-1), matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) play a critical role in LV remodelling.β-blockers are first line therapy for AMI and heart failure; however, the mechanisms responsible for their benefits remain poorly understood. Different β-blocker agents have been shown to exert beneficial activities both in AMI and heart failure, however, their role in early remodelling after ischemia/reperfusion is to be fully elucidated.We sought to compare the effect of 2 of the most prescribed β-blocker agents in early markers of LV remodelling after AMI.

Methods

A reperfused AMI was induced in Yorshire pigs, being randomized to early intravenous carvedilol, metoprolol or placebo. Twenty-four hours after reperfusion markers of early remodelling were addressed in the LV.

Results

The early administration of both β-blockers is able to significantly reduce macrophage infiltration as well as the expression and activity of MCP-1 and MMP-2 compared to placebo. The effects of carvedilol were much stronger than those of metoprolol. Conversely, carvedilol upregulated the expression TIMP-2 to a greater extent than metoprolol.

Conclusions

In an AMI model closely mimicking human pathophysiology, the early administration of carvedilol reduced the expression of markers associated with early LV remodelling to greater extent than metoprolol. These findings may explain the superior clinical benefits exerted by carvedilol in heart failure.     

Appropriateness and complications of the use of spironolactone in patients treated in a heart failure clinic

Objectives

The widespread use of spironolactone in patients with congestive heart failure (CHF) has resulted in side effects and complications. We analyzed a cohort of patients treated by a dedicated CHF team, in order to examine the tolerability and safety of spironolactone in clinical practice.

Methods

We retrospectively evaluated data on 157 patients who were followed by the Heart Failure clinic of whom 100 patients on maximal treatment (all on β blockers, 99% on ACE inhibitors) received spironolactone. The complications following spironolactone use were defined as: hyperkalemia with serum K 5.2 mEq/l; creatinine 2.0 mg/dl; hyponatremia with serum Na 135 mEq/l, hypotension and side effects such as gynecomastia and abdominal pain.

Results

At 1 year follow-up 6 patients developed hyperkalemia (range 5.3-5.9), 4 of them had K > 5.5 mEq/l. Two patients developed hyponatremia. Six patients stopped spironolactone for: 1-gynecomastia, 2-worsening renal failure and hyperkalemia, 2-hyperkalemia (5.9 mEq/l) and 1 for bradycardia. There was an increase in mean creatinine level at 1 year (1.12 ± 0.35 vs. 1.21 ± 0.38 mg/dl, p = 0.02), however, no significant changes were found in GFR (99.9 ± 33.5 vs. 65.7 ± 27.7 ml min^− 1 1.73 m^− 2, p = ns) and potassium (4.5 ± 0.4 vs. 4.6 ± 0.5 mEq/l, p = ns). We found improvement of GFR by > 10% in 19 patients and worsening by > 10% in 38 patients. No patient was hospitalized or required urgent treatment for spironolactone-related side effects.

Conclusions

In patients with CHF on optimal therapy with ACE inhibitors and β blockers appropriate spironolactone use and close follow-up by a dedicated HF team can minimize the risk for adverse events and complications.     

Patterns of beta-blocker utilization in patients with chronic heart failure: experience from a specialized outpatient heart failure clinic

Background

β-Blockers have been shown incontrovertibly to improve morbidity and survival in patients with heart failure. However, there is limited information regarding their use in clinical practice settings, and reasonable utilization targets for quality improvement initiatives have not been established.

Method

We identified 500 consecutive patients with chronic heart failure seen at a specialized outpatient heart failure clinic from March 2001 to May 2001, and retrospectively extracted clinical and drug information from an electronic medical record.

Results

In this cross-sectional analysis, the rate of β-blocker utilization was 69%. Seventy-five percent of patients had at least tried a β-blocker. Among those with β-blockers initiated, 16% experienced side effects that led to drug discontinuation (9.1%) or down-titration (6.9%) that was similar across all NYHA classes. A lower utilization rate of β-blockers was observed in patients of advanced age and those with diabetes mellitus, concomitant antiarrhythmic therapy, and preserved left ventricular ejection fraction (P < .05). Respiratory disease remained the most common reason for withholding β-blocker therapy, especially with severe obstructive (rather than restrictive) physiology.

Conclusion

It appears that about 70% of patients with chronic heart failure can be successfully treated with a β-blocker in a specialized heart failure outpatient setting where physicians are committed to β-blocker use in heart failure. It is possible that subgroups with lower utilization rates can be targeted for quality improvement initiatives.     

Improvement of left ventricular diastolic function induced by β-blockade: a comparison between nebivolol and metoprolol

Objectives

Enhanced adrenergic drive is involved in the development of left ventricular (LV) diastolic dysfunction observed in metabolic syndrome (MS). Thus, β-blockers might improve LV dysfunction observed in MS, but whether this occurs is unknown.

Methods

We assessed in Zucker fa/fa rats the effects of short- (5 days) and long-term (90 days) metoprolol (‘pure’ β-blockade; 80 mg/kg/day) or nebivolol (β-blocker with vasodilating properties; 5 mg/kg/day) treatment on LV hemodynamics and remodeling, as well as the long-term effects on coronary and peripheral endothelial dysfunction.

Results

At identical degree of β₁-receptor blockade, metoprolol and nebivolol decreased heart rate to the same extent and preserved cardiac output via increased stroke volume. None of the β-blockers, either after long- or short-term administration, modified LV end-systolic pressure-volume relation. Both β-blockers reduced, after long-term administration, LV end-diastolic pressure, Tau and end-diastolic pressure-volume relation, and this was associated with reduced LV collagen density, but not heart weight. Similar hemodynamic effects were also observed after short-term nebivolol, but not short-term metoprolol. These short-term effects of nebivolol were abolished by NO synthase inhibition. At the vascular level, nebivolol, and to a lesser extend metoprolol, improved NO dependent coronary vasorelaxation, which was abolished by NO synthase inhibition.

Conclusions

In a model of MS, the β-blockers metoprolol and nebivolol improve to the same extent LV hemodynamics, remodeling and diastolic function, but nebivolol prevent more markedly endothelium dependent vasorelaxation involving a more marked enhancement of NO bio-availability.     

Risk of intraoperative hypotension with loop diuretics: a randomized controlled trial

Background

There is growing concern regarding the safety of blood pressure-lowering medications administered during the perioperative period. Whether loop diuretics also induce intraoperative hypotension is uncertain. Our objective was to compare the effects of continuing or withholding furosemide on the day of noncardiac elective surgery on intraoperative hypotension among chronic users of furosemide.

Methods

A double blind, randomized, placebo controlled trial was conducted at 3 North American university centers between September 2000 and December 2006. Participants were randomly assigned in a 1:1 ratio to receive either furosemide or placebo on the day of surgery. The primary outcome was risk of developing intraoperative hypotension. A priori secondary outcomes included risk of heart failure; composite cardiovascular event (myocardial infarction, arrhythmia, stroke or transient ischemic attack, or death); and change in renal function and electrolytes.

Results

Of the 212 patients enrolled, 193 patients underwent surgery. There was no significant difference in risk of developing intraoperative hypotension between the furosemide (49%) and placebo (51.9%) groups (relative risk [RR], 0.95; 95% confidence interval [CI], 0.72-1.24; P = .78). The intraoperative administration of vasopressors and fluids were similar between both groups. The risk of developing postoperative cardiovascular events was not significantly different between those randomized to furosemide (4.8%) or placebo (2.8%) (RR, 1.73; 95% CI, 0.42-7.06; P = .49). There was no significant difference in renal function or electrolytes between the 2 groups.

Conclusion

Among elective, noncardiac surgeries in patients chronically treated with furosemide, the administration of furosemide on the day of surgery did not significantly increase the risk for intraoperative hypotension.     

Association between chronic heart failure and inhaled beta-2-adrenoceptor agonists

Background

Recent reports suggest an association between β-agonists and the risk of incident chronic heart failure (CHF). We sought to examine the association between inhaled β-agonists and risk of incident and nonincident heart failure.

Methods

We performed a nested case-control study within the Ambulatory Care Quality Improvement Project (ACQUIP). Case subjects were defined as having had a hospitalization with a primary discharge diagnosis of CHF. Controls were randomly selected from the ACQUIP cohort. The exposure was the number of β-agonist canisters filled in the 90 days before an index date.

Results

After adjusting for potentially confounding factors, there appeared to be no association between the use of inhaled β-agonists and the risk of heart failure (1-2 canisters per month, OR 1.3 [95% CI 0.9, 1.8], ≥3 canisters per month, 1.1 [95% CI 0.8, 1.6]). However, among the cohort that had a history of CHF, there appeared to be a dose-response association between the number of inhaled β-agonists and the risk of hospitalization for chronic heart failure (1-2 canisters per month, adjusted OR 1.8 [95% CI 1.1, 3.0], ≥3 canisters per month, adjusted OR 2.1 [95% CI 1.2, 3.8]).

Conclusion

β-Agonists did not appear to be associated with incident heart failure but were associated with risk of CHF hospitalization among those subjects with a previous CHF diagnosis. Although a causal relationship cannot be inferred from these findings, further research is warranted to determine the safety and effectiveness of inhaled β-agonists for patients with CHF.     

Coronary flow reserve abnormalities in patients with diabetes mellitus who have end-stage renal disease and normal epicardial coronary arteries

Background

Diabetic nephropathy is associated with increased cardiovascular events. Coronary atherosclerosis is responsible for many of these events, but other mechanisms such as impaired flow reserve may be involved. The purpose of this study was to define the prevalence and mechanism of abnormal coronary velocity reserve (CVR) in patients with diabetes mellitus who have nephropathy and a normal coronary artery.

Methods

Patients undergoing catheterization for clinical purposes were enrolled. CVR was measured with a Doppler ultrasound scanning wire in a normal coronary in 32 patients without diabetes mellitus, 11 patients with diabetes mellitus who did not have renal failure, and 21 patients with diabetes mellitus who had nephropathy. A CVR <2.0 was considered to be abnormal.

Results

Patients with diabetes mellitus who had renal failure had a higher incidence of hypertension and left ventricular hypertrophy. The average peak velocity (APV) at baseline was higher in patients with diabetes mellitus who had renal failure. At peak hyperemia, APV increased in all 3 groups, with no difference between groups. The mean CVR for patients without diabetes was 2.8 ± 0.8 and was not different from that in patients with diabetes mellitus who did not have renal failure (2.7 ± 0.7), but was lower than that in patients with diabetes mellitus who had renal failure (1.6 ± 0.5; P < 0.001). Abnormal CVR was observed in 9% of patients without diabetes mellitus, 18% of patients with diabetes mellitus who did not have renal failure, and 57% of patients with diabetes mellitus who had renal failure, and abnormal CVR was caused by an elevation of baseline APV in 66% of these cases. The baseline heart rate and the presence of diabetes mellitus with renal failure were independent predictors of abnormal CVR by multivariable analysis.

Conclusions

Patients with diabetic nephropathy have abnormalities in CVR in the absence of angiographically evident coronary disease.     

Renal insufficiency and mortality from acute coronary syndromes

Background

Although there is accumulating evidence that renal insufficiency is an independent risk factor for mortality after acute myocardial infarction (AMI), it is not known whether renal dysfunction is associated with an increased mortality rate after a broad range of acute coronary syndromes, including unstable angina.

Methods

We examined consecutive patients from 24 Veterans Affairs hospitals with confirmed AMI or unstable angina between March 1998 and February 1999, who were categorized into groups according to estimated glomerular filtration rate (GFR). Multivariable regression was used to assess the independent association between GFR and the 7-month mortality rate, adjusting for differences in patient characteristics and treatment.

Results

Of the 2706 patients, 436 (16%) had normal renal function (GFR >90 mL/min/1.73 m²), 1169 (43%) had mild renal insufficiency (GFR 60-89 mL/min/1.73 m²), 864 (32%) had moderate renal insufficiency (GFR 30-59 mL/min/1.73 m²), and 237 (9%) had severe renal insufficiency (GFR <30 mL/min/1.73 m²). Patients with renal insufficiency were less likely to undergo coronary angiography or to receive aspirin or β-blockers at discharge. In multivariable models, renal insufficiency was associated with a higher odds of death (mild renal insufficiency: odds ratio [OR] = 1.76; 95% CI, 0.93-3.33; moderate renal insufficiency: OR = 2.72; 95% CI, 1.43-5.15; and severe renal insufficiency: OR = 6.18; 95% CI, 3.09-12.36; all compared with normal renal function). The associations between renal insufficiency and mortality rate were similar in both the AMI and unstable angina subgroups (P value for interaction = .45).

Conclusions

Renal insufficiency is common and is associated with higher risks for death in patients with a broad range of ACS at presentation. Future efforts should be dedicated to determining whether more aggressive treatment will optimize outcomes in this patient population.     

Effect of iodixanol and ioxilan on QT interval and renal function in patients with systolic heart failure

Background

Contrast media (CM) exposure is associated with a substantial risk of arrhythmias and nephrotoxicity. These adverse effects may be exacerbated in high-risk conditions such as heart failure, although no studies have evaluated newer CM agents in this population. This study evaluated the electrophysiologic and renal effects of two newer CM agents, iodixanol and ioxilan, in heart failure patients undergoing angiography.

Methods

Eighty-seven consecutive systolic heart failure patients who received either iso-osmolar iodixanol (n = 44) or low-osmolar ioxilan (n = 43), stratified for concomitant amiodarone, were evaluated for QT interval and serum creatinine changes in comparison to baseline. QT values were corrected according to three formulae: Bazett's correction, Fridericia formula, and Framingham equation.

Results

Baseline patient characteristics were not significantly different in the iodixanol versus ioxilan groups, except for myocardial infarction and renal disease. No significant change in mean QTc was observed after exposure to either CM agent compared to baseline. These results were unaffected by amiodarone. A significant improvement in serum creatinine from baseline was observed in the iodixanol group compared to the ioxilan group (−0.121 ± 0.35 mg/dL vs. 0.033 ± 0.23 mg/dL, respectively; p = 0.045).

Conclusions

No significant change in QTc interval was observed in patients receiving either iodixanol or ioxilan during angiography. Iodixanol appeared to improve short-term renal function in patients with heart failure and should be further investigated.     

Clinical outcome of patients with heart failure and preserved left ventricular function

Background

Patients with heart failure have a poor prognosis. However, it has been presumed that patients with heart failure and preserved left ventricular function (LVF) may have a more benign prognosis.

Objectives

We evaluated the clinical outcome of patients with heart failure and preserved LVF compared with patients with reduced function and the factors affecting prognosis.

Methods

We prospectively evaluated 289 consecutive patients hospitalized with a definite clinical diagnosis of heart failure based on typical symptoms and signs. They were divided into 2 subsets based on echocardiographic LVF. Patients were followed clinically for a period of 1 year.

Results

Echocardiography showed that more than one third (36%) of the patients had preserved systolic LVF. These patients were more likely to be older and female and have less ischemic heart disease. The survival at 1 year in this group was poor and not significantly different from patients with reduced LVF (75% vs 71%, respectively). The adjusted survival by Cox regression analysis was not significantly different (P = .25). However, patients with preserved LVF had fewer rehospitalizations for heart failure (25% vs 35%, P < .05). Predictors of mortality in the whole group by multivariate analysis were age, diabetes, chronic renal failure, atrial fibrillation, residence in a nursing home, and serum sodium ≤ 135 mEq/L.

Conclusion

The prognosis of patients with clinical heart failure with or without preserved LVF is poor. Better treatment modalities are needed in both subsets.     

Beta-blocker therapy in patients with heart failure in the urban setting: moving beyond clinical trials

Background

Despite their known benefits, β-blockers (BBL) are not yet widely prescribed for heart failure, especially in the primary care setting. We wanted to identify patient characteristics that could guide primary care physicians in deciding whether they or a cardiologist should initiate BBL. A second objective was to determine the tolerability of BBL in clinical practice.

Methods

A retrospective chart review was conducted on a consecutive series of 551 patients with systolic dysfunction referred to a heart failure clinic in an urban public hospital. Patient responses to BBL were stratified into three categories: favorable (improvement of left ventricular ejection fraction by serial echocardiography), unfavorable (development of decompensated heart failure), or neither. Tolerability of BBL was assessed by the need to permanently discontinue BBL.

Results

Of 551 patients, 363 (66%) tolerated BBL. Among patients who had BBL initiated in the clinic, 48 had a favorable response, 34 had an unfavorable response, and 57 had neither a favorable or unfavorable response, as defined. A lower systolic blood pressure and higher diuretic dose were associated with development of decompensated heart failure as compared to improvement of ejection fraction.

Conclusions

A majority of patients with heart failure in an urban public hospital can tolerate BBL. Easily measurable characteristics such as lower systolic blood pressure and higher diuretic dose may assist primary care physicians in triaging patients for referral to cardiologists for β-blocker initiation.     

Successful weaning and explantation of the Heartmate II left ventricular assist device

Background

Ventricular assist devices (VADs) are used in cases of heart failure refractory to medical therapy. Most VADs are used as a bridge to heart transplantation; however, in certain cases, myocardial function recovers and VADs can be explanted after the patient is weaned. The objectives of this study were to describe patients who required Heartmate II VAD insertion, followed by myocardial recovery and explanation in a quaternary heart centre.

Methods

Patients who had a VAD explanted were identified in the mechanical support institutional database and their outcomes were analyzed. Clinical examinations, biochemical markers, and serial echocardiograms were used to demonstrate myocardial recovery.

Results

Seventeen patients had a Heartmate II VAD inserted between 2008 and 2010. Four patients underwent successful weaning and subsequent VAD explantation. Etiology of decompensated heart failure was idiopathic dilated cardiomyopathy (n = 1), ischemic (n = 1), or myocarditis (n = 2). Mean age was 35.3 years. Patients were supported for 213 days (range 70-293 days) and were in New York Heart Association class I in the community before explantation. The devices were explanted via a minimally invasive approach, without cardiopulmonary bypass. All patients survived explantation and were discharged alive from hospital after an average of 5.7 ± 1.5 days post pump explantation. No adverse events were reported after explantation. Only one patient required allogenic blood transfusion after the procedure.

Conclusions

Patients requiring VAD support for myocardial failure can undergo significant reverse remodelling. Explantation can lead to optimal outcome with minimal morbidity. Methods for assessment of reverse remodelling, weaning protocol, and optimal timing of explantation remain under evaluation.     

New York Heart Association Functional class influences the impact of diabetes on cardiac autonomic function

Background

Diabetes (D) and heart failure (HF) are associated with abnormal heart rate variability (HRV). It is unclear whether the HRV effect of having both is cumulative.

Methods

Pretreatment HRV (traditional, nonlinear, and heart rate [HR] turbulence) in 80 D versus 74 non-D (ND) systolic HF patients was compared by New York Heart Association II versus III among patients entered into an HF drug evaluation study.

Results

Age-adjusted HR was lower in class II D versus class III and most HRV including HR turbulence was better in class II ND versus all others, with few differences between class II D and class III ND and D patients.

Conclusion

The effect of D and HF on autonomic function may be cumulative in class II, but D may have little additional effect on most HRV in class III patients. The prognostic value of different HRV measures in D versus ND HF patients should be further investigated.     

Incident Hyperkalemia,Hypokalemia, and Clinical Outcomes During Spironolactone Treatment of Heart Failure With Preserved Ejection Fraction: Analysis of the TOPCAT Trial

Background

In patients with heart failure and preserved ejection fraction (HF-PEF) randomized in the Americas as part of the Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist (TOPCAT) trial, treatment with spironolactone enhanced the risk of hyperkalemia but reduced the risk of hypokalemia. We examined the clinical correlates and prognostic implications of incident hypo- and hyperkalemia during study follow-up.

The diagnostic utility of heart rate-corrected ST-segment depression during adenosine nuclear stress testing

Background

Vasodilator stress testing relies heavily on the imaging portion so that clinically useful information from the electrocardiogram may be overlooked. Stress-induced ST-segment depression, although uncommon, is highly predictive of severe disease. We investigated whether minor ST depressions during adenosine nuclear stress testing corrected for the modest heart rate increases (ST/HR slope and ST/HR index) might be clinically relevant.

Methods

The study included 74 consecutive patients with electrocardiograms interpretable for ischemia who underwent coronary angiography within the following 6 months.

Results

Abnormal responses using conventional thresholds for ischemic ST depression, the ST/HR slope, and ST/HR index were present in 8%, 20%, and 27%, respectively. The sensitivity for conventional ST depression was 11% and, when corrected for heart rate, increased to 27% and 36%, (P = .012), without adversely affecting the high positive predictive accuracy (83%, 80%, and 80%). Even with a normal perfusion scan, heart rate correction was highly predictive of multivessel coronary artery disease (4/5 patients).

Summary

Heart rate correction of ST depression during adenosine nuclear stress improves on conventional ST depression and may compliment perfusion imaging in detecting multivessel disease.     

Cystatin C in Acute Heart Failure Without Advanced Renal Impairment

Background

The prognostic value of cystatin C relative to glomerular filtration rate (GFR) estimated by the Modification of Diet in Renal Disease Study (MDRD) equation modified for Japan has not been investigated in acute heart failure patients with normal to moderately impaired renal function. More accurate detection of mild renal impairment might improve the risk stratification of heart failure patients, especially patients with normal to moderately impaired renal function.

Methods

Cystatin C and creatinine levels were measured on admission in 328 consecutive patients hospitalized for worsening chronic heart failure with a GFR estimated by MDRD equation modified for Japan ≥30 mL/min/1.73 m².

Results

During a median follow-up period of 915 days, there were 52 (16%) cardiac deaths. In stepwise Cox regression analyses including cystatin C and GFR estimated by MDRD equation modified for Japan (either as continuous variables or as variables categorized into quartiles), cystatin C (P <.0001), but not GFR estimated by MDRD equation modified for Japan, was independently associated with cardiac mortality. Adjusted relative risk according to the quartiles of these markers and Kaplan-Meier analyses revealed that the cystatin C was a better marker to separate low-risk from high-risk patients. Furthermore, receiver-operating characteristic curve analyses of these markers revealed that cystatin C showed a higher precision in predicting cardiac mortality.

Conclusion

Measurements of cystatin C might improve early risk stratification compared with GFR estimated by MDRD equation modified for Japan in acute heart failure patients with normal to moderately impaired renal function.     

Effects of diabetes mellitus and ischemic heart disease on the progression from asymptomatic left ventricular dysfunction to symptomatic heart failure: a retrospective analysis from the Studies of Left Ventricular Dysfunction (SOLVD) Prevention trial

Background

Emerging data suggest that diabetes mellitus is a risk factor for the progression of established heart failure only in those patients with ischemic cardiomyopathy. Whether diabetes mellitus is a risk factor for the progression from asymptomatic left ventricular systolic dysfunction to symptomatic heart failure in patients with left ventricular dysfunction of an ischemic cause is not known.

Methods

We performed a retrospective analysis of 2821 patients with asymptomatic left ventricular systolic dysfunction from the Studies of Left Ventricular Dysfunction (SOLVD) Prevention trial. We used adjusted survival analysis to examine the effects of ischemic heart disease and diabetes mellitus on 3 prespecified study end points: (1) development of heart failure (HF) symptoms, (2) HF hospitalization, and (3) death or development of symptoms.

Results

There is a statistically significant interaction between the cause of left ventricular systolic dysfunction and diabetes mellitus on the risk of development of heart failure symptoms (P = .020). Patients with ischemic cardiomyopathy and diabetes had an increased risk of progression to symptomatic heart failure (HR = 1.56, P < .001), hospitalization for heart failure (HR = 2.16, P < .001), and death or development of symptoms (HR = 1.50, P < .001), compared with patients with ischemic cardiomyopathy without diabetes. In contrast, diabetes was not associated with an increased risk of reaching these end points in patients with nonischemic cardiomyopathy.

Conclusions

Diabetes mellitus is a risk factor for the progression from asymptomatic left ventricular systolic dysfunction to symptomatic heart failure, but this risk appears to be confined to those patients with ischemic cardiomyopathy.     

The effects of enhanced external counterpulsation on time- and frequency-domain measures of heart rate variability

Background and Purpose

We hypothesized that symptom improvement from enhanced external counterpulsation (EECP) is related to improved heart rate variability (HRV).

Methods

This prospective, multicenter study enrolled 27 patients with angina who underwent 48-hour ambulatory electrocardiogram monitoring at baseline, immediately after 35 hours of EECP, and at 1 month. Primary end points included change in time-domain (SD of normal-to-normal intervals) and frequency-domain HRV.

Results

Twenty-four patients completed the full course of EECP therapy and 3 ambulatory electrocardiograms. There were no significant changes in time-domain HRV measures after EECP. Patients younger than 65 years and those with heart failure had improved SD of normal-to-normal interval after EECP (P = .02). Although frequency-domain HRV measures did not change in the overall cohort, patients with diabetes had improved daytime low-frequency power (P = .016).

Conclusions

There was no significant change in the time- or frequency-domain HRV measures after EECP. In diabetic individuals, there was an increase in low-frequency HRV, which has been associated with reduced mortality.