Prognostic value of the QRS duration in patients with heart failure: a subgroup analysis from 24 centers of Val-HeFT

Mortality and Cardiovascular End Points In Relation to the Aortic Pulse Wave Components: An Individual-Participant Meta-Analysis

BACKGROUND

Wave separation analysis enables individualized evaluation of the aortic pulse wave components. Previous studies focused on the pressure height with overall positive but differing results. In the present analysis, we assessed the associations of the pressure of forward and backward (Pfor and Pref) pulse waves with prospective cardiovascular end points, with extended analysis for time to pressure peak (Tfor and Tref).

METHODS

Participants in 3 IDCARS (International Database of Central Arterial Properties for Risk Stratification) cohorts (Argentina, Belgium, and Finland) aged ≥20 years with valid pulse wave analysis and follow-up data were included. Pulse wave analysis was done using the SphygmoCor device, and pulse wave separation was done using the triangular method. The primary end points consisted of cardiovascular mortality and nonfatal cardiovascular and cerebrovascular events. Multivariable-adjusted Cox regression was used to calculate hazard ratios.

RESULTS

A total of 2206 participants (mean age, 57.0 years; 55.0% women) were analyzed. Mean±SDs for Pfor, Pref, Tfor, and Tfor/Tref were 31.0±9.1 mm Hg, 20.8±8.4 mm Hg, 130.8±35.5, and 0.51±0.11, respectively. Over a median follow-up of 4.4 years, 146 (6.6%) participants experienced a primary end point. Every 1 SD increment in Pfor, Tfor, and Tfor/Tref was associated with 27% (95% CI, 1.07-1.49), 25% (95% CI, 1.07-1.45), and 32% (95% CI, 1.12-1.56) higher risk, respectively. Adding Tfor and Tfor/Tref to existing risk models improved model prediction (∆Uno's C, 0.020; P<0.01).

CONCLUSIONS

Pulse wave components were predictive of composite cardiovascular end points, with Tfor/Tref showing significant improvement in risk prediction. Pending further confirmation, the ratio of time to forward and backward pressure peak may be useful to evaluate increased afterload and signify increased cardiovascular risk.

The electrocardiogram in non-ischaemic-dilated cardiomyopathy

This article summarizes the main electrocardiogram (ECG) findings in dilated cardiomyopathy (DCM) patients. Recent reports are described in the great 'pot' of DCM peculiar ECG patterns that are typical of specific forms of DCM. Patients with late gadolinium enhancement on CMR, who are at greatest arrhythmic risk, have also distinctive ECG features. Future studies in large DCM populations should evaluate the diagnostic and prognostic value of the ECG.

Prevalence, risk factors and survival in dogs with myxomatous valve degeneration

ABSTRACT The objective of this study was to describe the prevalence, survival time, and risk factors of myxomatous mitral valve disease (MMVD) in dogs by a retrospective observational cohort study design of a Brazilian veterinary center, admitted from 2012 to 2018 (2.585 days). Considering the 105 dog files confirmed as MMVD, the prevalence of the disease was higher in small-breed dogs with ages from 10 to 19 years (30.3%). The survival time of the dogs at B1 stage (1.854 ± 145 days) was higher than the B2 (1.508+209) and C/D (930 ± 209). Higher risks of death (hazard ratio) were detected in the presence of syncope (2.5), pulmonary crackling (2.0), dyspnea (1.9), and higher values of vertebral heart scale (1.7), radiographic left atrium dimension (1.8), the ACVIM staging (1.7), and the duration of QRS complex (1.05). The results achieved demonstrated higher prevalence of MMVD in old small-breed dogs, associated with longer survival time in the B1 stage of the disease, and higher risk of death related to the presence of clinical signs, such as dyspnea, syncope, and pulmonary crackling, beyond some radiographic, echocardiographic, and electrocardiographic variables of heart or atrial enlargement.

Electroanatomic Ratios and Mortality in Patients With Heart Failure: Insights from the ASIAN-HF Registry

Background

QRS duration (QRSd) is a marker of electrical remodeling in heart failure. Anthropometrics and left ventricular size may influence QRSd and, in turn, may influence the association between QRSd and heart failure outcomes.

Methods and Results

Using the prospective, multicenter, multinational ASIAN‐HF (Asian Sudden Cardiac Death in Heart Failure) registry, this study evaluated whether electroanatomic ratios (QRSd indexed for height or left ventricular end‐diastole volume) are associated with 1‐year mortality in individuals with heart failure with reduced ejection fraction. The study included 4899 individuals (aged 60±19 years, 78% male, mean left ventricular ejection fraction: 27.3±7.1%). In the overall cohort, QRSd was not associated with all‐cause mortality (hazard ratio [HR], 1.003; 95% CI, 0.999–1.006, P=0.142) or sudden cardiac death (HR, 1.006; 95% CI, 1.000–1.013, P=0.059). QRS/height was associated with all‐cause mortality (HR, 1.165; 95% CI, 1.046–1.296, P=0.005 with interaction by sex p_interaction=0.020) and sudden cardiac death (HR, 1.270; 95% CI, 1.021–1.580, P=0.032). QRS/left ventricular end‐diastole volume was associated with all‐cause mortality (HR, 1.22; 95% CI, 1.05–1.43, P=0.011) and sudden cardiac death (HR, 1.461; 95% CI, 1.090–1.957, P=0.011) in patients with nonischemic cardiomyopathy but not in patients with ischemic cardiomyopathy (all‐cause mortality: HR, 0.94; 95% CI, 0.79–1.11, P=0.467; sudden cardiac death: HR, 0.734; 95% CI, 0.477–1.132, P=0.162).

Conclusions

Electroanatomic ratios of QRSd indexed for body size or left ventricular size are associated with mortality in individuals with heart failure with reduced ejection fraction. In particular, increased QRS/height may be a marker of high risk in individuals with heart failure with reduced ejection fraction, and QRS/left ventricular end‐diastole volume may further risk stratify individuals with nonischemic heart failure with reduced ejection fraction.

Registration

URL: https://Clinicaltrials.gov. Unique identifier: NCT01633398.

Prevalence and incidence of intra-ventricular conduction delays and outcomes in patients with heart failure and reduced ejection fraction: insights from PARADIGM-HF and ATMOSPHERE

AIMS

The importance of intra-ventricular conduction delay (IVCD), the incidence of new IVCD and its relationship to outcomes in heart failure and reduced ejection fraction (HFrEF) are not well studied. We addressed these questions in the PARADIGM-HF and ATMOSPHERE trials.

METHODS AND RESULTS

The risk of the primary composite outcome of cardiovascular death or heart failure hospitalization and all-cause mortality were estimated by use of Cox regression according to baseline QRS duration and morphology in 11 861 patients without an intracardiac device. At baseline, 1789 (15.1%) patients had left bundle branch block (LBBB), 524 (4.4%) right bundle branch block (RBBB), 454 (3.8%) non-specific IVCD, 2588 (21.8%) 'mildly abnormal' QRS (110-129 ms) and 6506 (54.9%) QRS <110 ms. During a median follow-up of 2.5 years, the risk of the primary composite endpoint was higher among those with a wide QRS, irrespective of morphology: hazard ratios (95% confidence interval) LBBB 1.36 (1.23-1.50), RBBB 1.54 (1.31-1.79), non-specific IVCD 1.65 (1.40-1.94) and QRS 110-129 ms 1.35 (1.23-1.47), compared with QRS duration <110 ms. A total of 1234 (15.6%) patients developed new-onset QRS widening ≥130 ms (6.1 per 100 patient-years). Incident LBBB occurred in 495 (6.3%) patients (2.4 per 100 patient-years) and was associated with a higher risk of the primary composite outcome [hazard ratio 1.42 (1.12-1.82)].

CONCLUSION

In patients with HFrEF, a wide QRS was associated with worse clinical outcomes irrespective of morphology. The annual incidence of new-onset LBBB was around 2.5%, and associated with a higher risk of adverse outcomes, highlighting the importance of repeat electrocardiogram review.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT0083658 (ATMOSPHERE) and NCT01035255 (PARADIGM-HF).

Evaluation of ivabradine in left ventricular dyssynchrony and reverse remodeling in patients with chronic heart failure

OBJECTIVES

Ivabradine is a pharmacological agent used in patients with heart failure and sinus rhythm. Its only known pharmacological effect is to slow the heart rate. In this study, we investigated the impact of ivabradine on dyssynchrony parameters in heart failure patients.

METHODS

In this study, we assigned 55 patients taking medication for heart failure to receive ivabradine in addition (Group I). Twenty healthy volunteers comprised Group II. Echocardiographic measurements (dyssynchrony, left ventricular volumes and left ventricular ejection fraction) were taken at baseline, 1 month, and 3 months.

RESULTS

A total of 32 heart failure patients in Group I completed the study. There was significant improvement in dyssynchrony parameters after ivabradine treatment in Group I. Interventricular dyssynchrony (IVD) decreased from 42.0 ± 24.4 milliseconds at baseline to 33.6 ± 20.7 milliseconds at 1 month (P = .001) and to 30.7 ± 19.4 milliseconds at 3 months (P < .001). Septal to posterior wall motion delay decreased from 90.3 ± 21.4 milliseconds to 83.9 ± 26.9 milliseconds (P = .011) at 1 month and to 81.5 ± 27.3 milliseconds at 3 months (P = .001). Septal to lateral Ts delay (Ts-SL) decreased from 42.7 ± 24.5 milliseconds to 35.8 ± 22.6 milliseconds at 1 month (P < .001) and to 34.8 ± 22.4 milliseconds at 3 months (P = .002). Left ventricular end-systolic volume (LVESV) decreased from 139.4 ± 42.2 mL to 135.3 ± 39.6 mL at 1 month (P = .006) and to 123.3 ± 39.5 mL at 3 months (P < .001).

CONCLUSION

The addition of ivabradine to heart failure treatment improves cardiac dyssynchrony parameters in chronic systolic heart failure patients with sinus rhythm.

Prognostic Value of QRS Duration among Patients with Cardiogenic Shock Complicating Acute Heart Failure: Data from the Korean Acute Heart Failure (KorAHF) Registry

Background and Objectives

Prolonged QRS duration is associated with poor outcomes in patients with chronic heart failure (HF). However, the prognostic value of QRS duration in patients with cardiogenic shock complicating acute HF remains unknown. We evaluated the hypothesis that prolonged QRS duration may be associated with short-term mortality among acute HF patients with cardiogenic shock (CS).

Methods

From March 2011 through December 2013, a total of 5,625 acute HF patients were consecutively enrolled in ten tertiary university hospitals. Among them, we analyzed patients who presented with CS. Patients were divided into three groups by QRS duration cutoff values of 130 and 150 ms. The primary endpoint was 30-day in-hospital mortality.

Results

Two hundred eleven patients presented with CS at admission and those with available electrocardiograms were included in this analysis. There were 35 patients with QRS durations of 150 ms or above, 30 patients with QRS durations between 130 ms and 150 ms, and 146 patients with QRS durations below 130 ms. The 30-day all cause in-hospital mortality rates were 43.7%, 33.1%, and 24.9%, respectively. After multivariate adjustment, severe prolonged QRS duration was a significant prognostic factor for 30-day in-hospital mortality (hazard ratio, 1.909; 95% confidence interval, 1.024–3.558; p=0.042).

Conclusions

Prolonged QRS duration was associated with a higher risk of 30-day in-hospital mortality among patients with acute HF who presented with CS.

Trial Registration

ClinicalTrials.gov Identifier: NCT01389843

Prognostic Impact and Predictors of Ejection Fraction Recovery in Patients With Alcoholic Cardiomyopathy

INTRODUCTION AND OBJECTIVES

Recovery of left ventricular ejection fraction (LVEF) has been described in alcoholic cardiomyopathy (ACM) after a period of alcohol withdrawal. Nevertheless, the prognostic impact of LVEF recovery in ACM and its determinants have not been studied. We sought to define the role of LVEF improvement in the long-term outcome of ACM and to identify predictors of LVEF recovery in these patients.

METHODS

We evaluated 101 ACM patients during a median follow-up period of 82 months [interquartile range 36-134].

RESULTS

At latest follow-up, 42 patients (42%) showed substantial LVEF recovery defined as an absolute increase in LVEF ≥ 10% to a final value of ≥ 40%. Patients who recovered LVEF had better outcomes than patients who did not (heart transplant or cardiovascular death 1% vs 30%; P <.001). A QRS with <120ms (OR, 6.68; 95%CI, 2.30-19.41), beta-blocker therapy (OR, 3.01; 95%CI, 1.09-8.28), and the absence of diuretics (OR, 3.35; 95%CI, 1.08-10.42) predicted LVEF recovery in multivariate analysis. Although alcohol cessation did not predict LVEF recovery, none of the patients (n=6) who persisted with heavy alcohol consumption recovered LVEF. The rate of patients who recovered LVEF did not differ between abstainers and moderate drinkers (44% vs 45%; P=.9).

CONCLUSIONS

The LVEF recovery is associated with an excellent prognosis in ACM. Beta-blocker treatment, QRS <120ms and absence of diuretics are independent predictors of LVEF recovery. LVEF recovery is similar in moderate drinkers and abstainers.

Combined assessment of myocardial damage and electrical disturbance in chronic heart failure

AIM

To investigate feasibility of combined assessment of biochemical and electrophysiological myocardial impairment markers risk-stratifying patients with chronic heart failure (CHF).

METHODS

Serum levels of heart-type fatty acid binding protein (H-FABP) as a marker of ongoing myocardial damage and QRS duration on electrocardiogram were measured at admission in 322 consecutive patients with CHF. A prolonged QRS duration was defined as 120 ms or longer. The cut-off value for H-FABP level (4.5 ng/mL) was determined from a previous study. Patients were prospectively followed during a median follow up period of 534 d. The primary endpoint was cardiac deaths and rehospitalization for worsening CHF.

RESULTS

There were 117 primary events, including 27 cardiac deaths and 90 rehospitalizations. Patients were stratified into four groups according to H-FABP level and QRS duration (≥ 120 ms). Multivariate analysis demonstrated that high H-FABP levels [hazard ratio (HR) = 1.745, P = 0.021] and QRS prolongation (HR 1.612, P = 0.0258) were independent predictors of cardiac events. Kaplan-Meier analysis demonstrated that the combination of high H-FABP levels and QRS prolongation could be used to reliably stratify patients at high risk for cardiac events (log rank test P < 0.0001).

CONCLUSION

Combined assessment of myocardial damage and electrical disturbance can be used to risk-stratify patients with CHF.

Canadian Cardiovascular Society/Canadian Heart Rhythm Society 2016 Implantable Cardioverter-Defibrillator Guidelines

Sudden cardiac death is a major public health issue in Canada. However, despite the overwhelming evidence to support the use of implantable cardioverter defibrillators (ICDs) in the prevention of cardiac death there remains significant variability in implantation rates across Canada. Since the most recent Canadian Cardiovascular Society position statement on ICD use in Canada in 2005, there has been a plethora of new scientific information to assist physicians in their discussions with patients considered for ICD implantation to prevent sudden cardiac death due to ventricular arrhythmias. We have reviewed, critically appraised, and synthesized the pertinent evidence to develop recommendations regarding: (1) ICD implantation in the primary and secondary prevention of sudden cardiac death in patients with and without ischemic heart disease; (2) when it is reasonable to withhold ICD implantation on the basis of comorbidities; (3) ICD implantation in patients listed for heart transplantation; (4) implantation of a single- vs dual-chamber ICD; (5) implantation of single- vs dual-coil ICD leads; (6) the role of subcutaneous ICDs; and (7) ICD implantation infection prevention strategies. We expect that this document, in combination with the companion article that addresses the implementation of these guidelines, will assist all medical professionals with the care of patients who have had or at risk of sudden cardiac death.

Usefulness of Electrocardiographic Patterns at Presentation to Predict Long-term Risk of Cardiac Death in Patients With Hypertrophic Cardiomyopathy

The objective of this study was to investigate the prognostic significance of 12-lead electrocardiogram (ECG) patterns in a large multicenter cohort of patients with hypertrophic cardiomyopathy; 1,004 consecutive patients with hypertrophic cardiomyopathy and a recorded standard ECG (64% men, mean age 50 ± 16 years) were evaluated at 4 Italian centers. The study end points were sudden cardiac death (SCD) or surrogates, including appropriate implanted cardiac defibrillator discharge and resuscitated cardiac arrest and major cardiovascular events (including SCD or surrogates and death due to heart failure, cardioembolic stroke, or heart transplantation). Prevalence of baseline electrocardiographic characteristics was: normal ECG 4%, ST-segment depression 56%, pseudonecrosis waves 33%, "pseudo-ST-segment elevation myocardial infarction (STEMI)" pattern 17%, QRS duration ≥120 ms 17%, giant inverted T waves 6%, and low QRS voltages 3%. During a mean follow-up of 7.4 ± 6.8 years, 77 patients experienced SCD or surrogates and 154 patients experienced major cardiovascular events. Independent predictors of SCD or surrogates were unexplained syncope (hazard ratio [HR] 2.5, 95% confidence interval [CI] 1.4 to 4.5, p = 0.003), left ventricular ejection fraction <50% (HR 3.5, 95% CI 1.9 to 6.7, p = 0.0001), nonsustained ventricular tachycardia (HR 1.7, 95% CI 1.1 to 2.6, p = 0.027), pseudo-STEMI pattern (HR 2.3, 95% CI 1.4 to 3.8, p = 0.001), QRS duration ≥120 ms (HR 1.8, 95% CI 1.1 to 3.0, p = 0.033), and low QRS voltages (HR 2.3, 95% CI 1.01 to 5.1, p = 0.048). Independent predictors of major cardiovascular events were age (HR 1.02, 95% CI 1.01 to 1.03, p = 0.0001), LV ejection fraction <50% (HR 3.73, 95% CI 2.39 to 5.83, p = 0.0001), pseudo-STEMI pattern (HR 1.66, 95% CI 1.13 to 2.45, p = 0.010), QRS duration ≥120 ms (HR 1.69, 95% CI 1.16 to 2.47, p = 0.007), and prolonged QTc interval (HR 1.68, 95% CI 1.21 to 2.34, p = 0.002). In conclusion, a detailed qualitative and quantitative electrocardiographic analyses provide independent predictors of prognosis that could be integrated with the available score systems to improve the power of the current model.

Natural history and prognostic factors in alcoholic cardiomyopathy

OBJECTIVES

This study sought to determine the natural history of contemporary alcoholic cardiomyopathy (ACM), to compare it with that of idiopathic dilated cardiomyopathy (IDCM), and to identify risk factors for poor outcome.

BACKGROUND

ACM is a common cause of dilated cardiomyopathy (DCM), but little is known about its natural history or the effect of reducing alcohol intake on disease progression.

METHODS

We studied the clinical characteristics and outcomes of 94 consecutive patients with ACM and 188 with IDCM, evaluated over the period between 1993 and 2011.

RESULTS

After a median follow-up of 59 months (interquartile range: 25 to 107 months), 14 ACM patients (15%) had died from cardiovascular causes (6 from heart failure and 8 from sudden cardiac death), 14 (15%) underwent heart transplantation, 35 (37%) experienced recovery in left ventricular function, and 31 (33%) remained clinically stable without improvement in systolic function. Transplantation-free survival was higher in ACM patients than in IDCM patients (p = 0.002), and ACM was associated with a favorable outcome on multiple analysis of the entire cohort (odds ratio [OR]: 0.4; 95% confidence interval [CI]: 0.2 to 0.8; p = 0.01). Independent predictors of death or heart transplantation in ACM identified by multiple logistic regression analysis were atrial fibrillation (OR: 9.7; 95% CI: 2.56 to 36.79; p = 0.001); QRS duration >120 ms (OR: 7.2; 95% CI: 2.02 to 26; p = 0.002), and lack of beta-blocker therapy (OR: 4.4; 95% CI: 1.35 to 14.49; p = 0.014). ACM patients who reduced their alcohol intake to moderate levels exhibited similar survival (p = 0.22) and cardiac function recovery (p = 0.8) as abstainers.

CONCLUSIONS

ACM has a better prognosis than IDCM. Atrial fibrillation, QRS width >120 ms, and the absence of beta-blocker therapy identify patients with a poor outcome. Alcohol abstainers and those who reduce intake to a moderate degree show similar clinical outcomes.

Short- and long-term outcomes depending on electrical dyssynchrony markers in patients presenting with acute heart failure: clinical implication of the first-degree atrioventricular block and QRS prolongation from the Korean Heart Failure registry

BACKGROUND

Prolongations of PR interval and QRS duration on 12-lead electrocardiogram are associated with atrioventricular and interventricular/intraventricular dyssynchrony, respectively. However, their clinical significance remains unclear in real-world heart failure (HF) population. We assessed whether the presence of first-degree atrioventricular block and/or QRS prolongation (≥120 ms) is associated with worse short- and long-term outcomes in patients with acute HF.

METHODS

The Korean Heart Failure is a nationwide registry of 3,200 consecutive patients presenting with acute HF at 24 centers in South Korea between June 2004 and April 2009. We selected 1,986 patients with sinus rhythm and divided them into 4 groups depending on the presence of first-degree atrioventricular block and/or QRS prolongation; ED_Neither (n = 1,347), ED_PR (n = 217), ED_QRS (n = 329), and ED_Both (n = 93) groups, respectively.

RESULTS

During the median follow-up of 18.2 months, overall death rate (17%, 22%, 20%, and 29%, P < .01) tended to rise with increasing number of electrical dyssynchrony markers. Patients in ED_Both group showed worst outcomes regarding the requirement of invasive managements during the index admission, in-hospital mortality, postdischarge death/rehospitalization, and cardiac device implantation. In time-dependent Cox regression analyses, presence of both PR >200 ms and QRS ≥120 ms was independently associated with in-hospital death (P < .01), postdischarge death/rehospitalization (P = .03), cardiac device implantation (P < .01), and overall death (P < .01).

CONCLUSIONS

A combined analysis of electrical dyssynchrony markers (PR prolongation and QRS widening) might be useful for short- and long-term risk stratifications of patients with acute HF.

Cerebral blood flow as a marker for recovery of left ventricular systolic dysfunction in patients with idiopathic dilated cardiomyopathy

BACKGROUND

This study was intended to investigate whether cerebral blood flow (CBF) could predict the recovery of left ventricular (LV) systolic dysfunction in patients with idiopathic dilated cardiomyopathy (DCMP).

METHODS AND RESULTS

Between July 2001 and March 2009, 107 patients who had been diagnosed with idiopathic DCMP underwent radionuclide angiography to assess their CBF. The recovery of LV systolic dysfunction was defined as recovery of the ejection fraction (EF) measured by transthoracic echocardiography to a level of 40% or greater and an increase of 10% or greater in its absolute value during follow-up. The EF was followed for at least 36 months if it did not recover. Thirty-four patients (31.8%) recovered and had greater CBF than the nonrecovered patients (41.9 ± 3.4 vs. 37.1 ± 4.9 mL/min/100g, P < .001). On multivariate logistic analysis, CBF (odds ratio 1.216) and symptom duration (odds ratio 0.952) were independent predictors of the recovery of LV systolic dysfunction. There was also a weak negative correlation between CBF and symptom duration (r = -0.334, P < .001). Furthermore, CBF was associated with LVEF improvement seen at the 1- and 2-year follow-up times according to multiple linear regression analysis.

CONCLUSIONS

CBF was associated with recovery of LV systolic dysfunction in patients with idiopathic DCMP. Therefore, measurement of CBF would be helpful to predict the clinical course of their disease.

Changing characteristics and mode of death associated with chronic heart failure caused by left ventricular systolic dysfunction: a study across therapeutic eras

BACKGROUND

Therapies for patients with chronic heart failure caused by left ventricular systolic dysfunction have advanced substantially over recent decades. The cumulative effect of these therapies on mortality, mode of death, symptoms, and clinical characteristics has yet to be defined.

METHODS AND RESULTS

This study was a comparison of 2 prospective cohort studies of outpatients with chronic heart failure caused by left ventricular systolic dysfunction performed between 1993 and 1995 (historic cohort: n=281) and 2006 and 2009 (contemporary cohort: n=357). In the historic cohort, 83% were prescribed angiotensin-converting enzyme inhibitors and 8.5% were prescribed β-adrenoceptor antagonists, compared with 89% and 80%, respectively, in the contemporary cohort. Mortality rates over the first year of follow-up declined from 12.5% to 7.8% between eras (P=0.04), and sudden death contributed less to contemporary mortality (33.6% versus 12.7%; P<0.001). New York Heart Association class declined between eras (P<0.001). QTc dispersion across the chest leads declined from 85 ms (SD, 2) to 34 ms (SD, 1) and left ventricular end-diastolic dimensions declined from 65 mm (SD, 0.6) to 59 mm (SD, 0.5) (both P<0.001).

CONCLUSIONS

Survival has significantly improved in patients with chronic heart failure caused by left ventricular systolic dysfunction over the past 15 years; furthermore, sudden death makes a much smaller contribution to mortality, and noncardiac mortality is a correspondingly greater contribution. This has been accompanied by an improvement in symptoms and some markers of adverse electric and structural left ventricular remodeling.

Electrocardiographic and cardiac magnetic resonance imaging parameters as predictors of a worse outcome in patients with idiopathic dilated cardiomyopathy

Aims

Clinical parameters are weak predictors of outcome in patients with idiopathic dilated cardiomyopathy (IDC). We assessed the prognostic value of cardiac magnetic resonance (CMR) parameters in addition to conventional clinical and electrocardiographic characteristics.

Methods and results

One hundred and forty-one IDC patients were studied. QRS and QTc intervals were measured in 12-lead surface electrocardiogram. Patients were followed for median 1339 days, including 483 patient-years. The primary endpoint—cardiac death or sudden death—occurred in 25 (18%) patients, including 16 patients with cardiac death, 3 patients with sudden cardiac death (SCD), and 6 patients with ICD shock. Late gadolinium enhancement (LGE) was detected in 36 patients (26%). Kaplan–Meier survival analysis displayed QRS >110 ms (P = 0.010), the presence of LGE (P = 0.037), and diabetes mellitus (P < 0.001) as significant parameters for a worse outcome. Multivariable analysis revealed cardiac index (P < 0.001), right ventricular end-diastolic volume index (RVEDVI) (P = 0.006) derived from CMR imaging, the presence of diabetes mellitus (P = 0.006), and QRS >110 ms (P = 0.045) as significant predictors for the primary endpoint.

Conclusion

Cardiac index and RVEDVI derived from CMR imaging in addition to QRS duration >110 ms from conventional surface ECG and diabetes mellitus provide prognostic impact for cardiac death and SCD in patients with IDC.

Intracellular calcium modulation of voltage-gated sodium channels in ventricular myocytes

AIMS

Cardiac voltage-gated sodium channels control action potential (AP) upstroke and cell excitability. Intracellular calcium (Ca(i)(2+)) regulates AP properties by modulating various ion channels. Whether Ca(i)(2+) modulates sodium channels in ventricular myocytes is unresolved. We studied whether Ca(i)(2+) modulates sodium channels in ventricular myocytes at Ca(i)(2+) concentrations ([Ca(i)(2+)]) present during the cardiac AP (0-500 nM), and how this modulation affects sodium channel properties in heart failure (HF), a condition in which Ca(i)(2+) homeostasis is disturbed.

METHODS AND RESULTS

Sodium current (I(Na)) and maximal AP upstroke velocity (dV/dt(max)), a measure of I(Na), were studied at 20 and 37 degrees C, respectively, in freshly isolated left ventricular myocytes of control and HF rabbits, using whole-cell patch-clamp methodology. [Ca(i)(2+)] was varied using different pipette solutions, the Ca(i)(2+) buffer BAPTA, and caffeine administration. Elevated [Ca(i)(2+)] reduced I(Na) density and dV/dt(max), but caused no I(Na) gating changes. Reductions in I(Na) density occurred simultaneously with increase in [Ca(i)(2+)], suggesting that these effects were due to permeation block. Accordingly, unitary sodium current amplitudes were reduced at higher [Ca(i)(2+)]. While I(Na) density and gating at fixed [Ca(i)(2+)] were not different between HF and control, reductions in dV/dt(max) upon increases in stimulation rate were larger in HF than in control; these differences were abolished by BAPTA.

CONCLUSION

Ca(i)(2+) exerts acute modulation of I(Na) density in ventricular myocytes, but does not modify I(Na) gating. These effects, occurring rapidly and in the [Ca(i)(2+)] range observed physiologically, may contribute to beat-to-beat regulation of cardiac excitability in health and disease.

The electrocardiogram as a prognostic tool for predicting major cardiac events

Among patients with cardiac disease, the identification of those who are at low risk and those who are at high risk for major cardiac events is crucial for a rational clinical management of individual patients. A correct noninvasive risk stratification of cardiac patients, in particular, has relevant clinical implications because it would avoid unnecessary exposure to potentially risky invasive diagnostic or interventional procedures in low-risk patients, whereas it would allow an appropriate aggressive diagnostic and therapeutic approach in high-risk patients. Furthermore, the appropriate identification of low- and high-risk patients would also have social and economic implications by favoring optimization of resource distribution and costs. A large number of studies in previous decades provided evidence that several methods and variables derived from the analysis of the electrocardiogram (ECG) are powerful predictors of major cardiac events in several clinical conditions. Despite that, there has been limited attention about how several of these findings can be used in clinical practice. Furthermore, in recent years, most studies about risk stratification of cardiac patients have mainly been focused on the use of a number of serum/plasma biomarkers with reduced attention to ECG variables. Surprisingly, however, there have been few attempts to establish whether the various proposed risk markers add any significant information to that obtainable from ECG methods. In this article, the evidence for the prognostic value of variables derived from the assessment of the ECG signal by several methods and techniques will be briefly reviewed. Because of the largeness of the topic, this review will be necessarily incomplete. Because most of the clinical research in this field concerned risk stratification of patients with coronary artery disease, the article will be largely focused on this population of patients. The role of ECG methods in specific cardiac diseases and, in particular, in the general population of asymptomatic subjects will be briefly discussed when believed appropriate and helpful. Furthermore, only major clinical events (ie, cardiac death, arrhythmic events, acute myocardial infarction) will be taken into account as end points in this article. Minor clinical events (eg, coronary revascularization procedures, coronary artery restenosis, recurrences of symptoms) are indeed less robust as end points because they are widely biased by subjective judgments.

Relation of QRS duration to mortality in a community-based cohort with hypertrophic cardiomyopathy

A prolonged QRS duration on the standard electrocardiogram is associated with an increased risk of cardiovascular death in cardiomyopathies of different origin. However, the relation between QRS duration and prognosis in hypertrophic cardiomyopathy (HC) remains undefined. We assessed the relation between QRS duration and cardiovascular death in 241 consecutive patients with HC. The study cohort was divided into 2 groups according to QRS duration: <120 and > or =120 ms. Of the 241 patients, 191 (79%) had a QRS duration <120 ms and 50 (21%) a QRS duration > or =120 ms. During a mean follow-up of 7.9 +/- 5.1 years, 35 patients died of cardiovascular causes related to HC. Of these 35 patients, 13 (6%) had a QRS duration <120 ms and 22 (43%) had a QRS duration > or =120 ms (p <0.01). Risk of cardiovascular death was significantly higher in patients with a QRS duration > or =120 ms than in those with a QRS duration <120 ms (relative risk 5.2, p <0.0001). At 8-year follow-up, cumulative risks of HC-related death were 7.1% in patients with a QRS duration <120 ms and 55% in those with a QRS duration > or =120 ms. Multivariate analysis confirmed that a QRS duration > or =120 ms was independently associated with an increased risk of cardiovascular death (hazard ratio 3.2, p = 0.007). New York Heart Association functional class III/IV was the only other clinical variable significantly and independently associated with an increased risk of cardiovascular death. In conclusion, in patients with HC, QRS duration on standard electrocardiogram is directly related to cardiovascular mortality, and a QRS duration > or =120 ms is a strong and independent predictor of prognosis.

Prevalence and prognostic impact of bundle branch block in patients with heart failure: evidence from the CHARM programme

BACKGROUND

Bundle branch block (BBB) is a powerful independent predictor of cardiovascular mortality in patients with heart failure (HF) and reduced left ventricular ejection fraction (LVEF). The prognostic implications in HF with preserved systolic function (HF-PSF) are less well understood.

METHODS

The Candesartan in Heart failure: Assessment of Reduction in Mortality and morbidity (CHARM) programme randomised 7599 patients with symptomatic HF to receive candesartan or placebo. The primary outcome comprised cardiovascular death or HF hospitalisation. The relative risk conveyed by BBB relative to a normal electrocardiogram was examined.

RESULTS

The prevalence of BBB was significantly lower in patients with preserved compared with reduced systolic function (CHARM-Preserved 14.4%, Alternative 29.6%, Added 30.5%), p<0.0001. Overall, the adjusted hazard ratio for the primary outcome was 1.48 (95% confidence interval 1.22-1.78), p<0.0001, reflecting increased risk in patients with reduced LVEF (1.72 [1.28-2.31], p=0.0003). The apparently more modest risk among patients with HF-PSF was significant in unadjusted (1.80 [1.37-2.37], p<0.0001) but not adjusted analysis (1.16 [0.88-1.54], p=0.2897). However, no formal statistical difference was observed between the two cohorts, and interpretation is limited by the unknown prevalence of left and right BBB morphologies in each. Comparing BBB presence with absence yielded qualitatively similar results.

CONCLUSION

The simple clinical finding of BBB is a powerful independent predictor of worse clinical outcomes in patients with HF and reduced LVEF. It is less frequent, with a more modest predictive effect, in patients with preserved systolic function.

Abnormal Conduction Increases Risk of Adverse Outcomes From Right Ventricular Pacing

OBJECTIVES

The purpose of this study was to determine whether QRS duration or morphology increased the risk of adverse outcome in the DAVID (Dual Chamber and VVI Implantable Defibrillator) trial.

BACKGROUND

The DAVID trial found an increased risk of the combined end point of death and new or worsening congestive heart failure (CHF) in defibrillator recipients who were paced DDDR-70 versus VVI-40.

METHODS

We analyzed the combined end point in patients with abnormal QRS duration (AbQRS) (> or =110 ms) compared with those with normal QRS duration (NQRS) (<110 ms).

RESULTS

The QRS data were available for 496 of the 506 patients enrolled in the trial, including 223 patients with NQRS (45%) and 273 patients with AbQRS (55%). In patients in whom defibrillators were programmed to pace infrequently (VVI-40), having an NQRS or AbQRS was not an indicator of increased risk of adverse outcome. However, among patients in whom defibrillators were programmed in a manner that promoted more frequent ventricular pacing (DDDR-70), there was a significant adverse interaction with AbQRS; this combination was independently associated with a higher risk for developing CHF or death (p = 0.017).

CONCLUSIONS

Although patients with AbQRS tended to have other risk factors associated with poor outcome, the interaction of QRS duration with ventricular pacing (DDDR-70) independently contributed to a worse outcome and therefore, was a marker of patients in whom such treatment may be harmful. This should not imply that right ventricular pacing in NQRS patients is safe but rather that pacing in the context of an AbQRS is probably best avoided.

Association of QRS duration and outcomes after myocardial infarction: the VALIANT trial

BACKGROUND

Prolongation of the QRS duration has been shown to be associated with adverse outcomes among heart failure (HF) patients. The association of QRS duration with clinical outcomes in the post-myocardial infarction (MI) setting is less well defined.

OBJECTIVES

To assess the prognostic significance of QRS duration prolongation on initial electrocardiogram after acute MI.

METHODS

QRS duration was measured in 403 patients with MI complicated by left ventricular dysfunction, signs or symptoms of HF, or both, who were enrolled in the Valsartan in Acute Myocardial Infarction (VALIANT) echo study. The cohort was divided into quartiles of QRS duration (<75 ms, 75-88 ms, 89-108 ms, >108 ms). The number of clinical events were determined and compared across the groups.

RESULTS

Increasing QRS duration is associated with a higher incidence of HF, sudden death (SD), and cardiovascular (CV) death (P-trend <0.05) but not with stroke or recurrent MI. The univariate relative risks for HF, SD, and CV death with increasing QRS duration quartiles were 1.31 (95% CI, 1.06-1.64), 1.57 (95% CI, 1.03-2.40), and 1.31 (95% CI, 1.03-1.66), respectively, but QRS duration did not remain independently predictive of adverse outcome after adjusting for the 10 most predictive baseline covariates. Baseline end-diastolic and end-systolic volumes were larger and ejection fraction was lower in the higher QRS quartile groups.

CONCLUSIONS

Prolonged QRS duration, even within the normal range, is associated with larger ventricular volumes, reduced systolic function, and an increased risk for development of HF, SD, and CV death after MI but appears to be a marker, rather than an independent predictor, for increased risk.