Conduit Flow Compensates for Impaired Left Atrial Passive and Booster Functions in Advanced Diastolic Dysfunction

BACKGROUND

Quantification of left atrial (LA) conduit function and its contribution to left ventricular (LV) filling is challenging because it requires simultaneous measurements of both LA and LV volumes. The functional relationship between LA conduit function and the severity of diastolic dysfunction remains controversial. We studied the role of LA conduit function in maintaining LV filling in advanced diastolic dysfunction.

METHODS

We performed volumetric and flow analyses of LA function across the spectrum of LV diastolic dysfunction, derived from a set of consecutive patients undergoing multiphasic cardiac computed tomography scanning (n=489). From LA and LV time-volume curves, we calculated 3 volumetric components: (1) early passive emptying volume; (2) late active (booster) volume; and (3) conduit volume. Results were prospectively validated on a group of patients with severe aortic stenosis (n=110).

RESULTS

The early passive filling progressively decreased with worsening diastolic function (P<0.001). The atrial booster contribution to stroke volume modestly increases with impaired relaxation (P=0.021) and declines with more advanced diastolic function (P<0.001), thus failing to compensate for the reduction in early filling. The conduit volume increased progressively (P<0.001), accounting for 75% of stroke volume (interquartile range, 63-81%) with a restrictive filling pattern, compensating for the reduction in both early and booster functions. Similar results were obtained in patients with severe aortic stenosis. The pulmonary artery systolic pressure increased in a near-linear fashion when the conduit contribution to stroke volume increased above 60%. Maximal conduit flow rate strongly correlated with mitral E-wave velocity (r=0.71; P<0.0001), indicating that the increase in mitral E wave in diastolic dysfunction represents the increased conduit flow.

CONCLUSIONS

An increase in conduit volume contribution to stroke volume represents a compensatory mechanism to maintain LV filling in advanced diastolic dysfunction. The increase in conduit volume despite increasing LV diastolic pressures is accomplished by an increase in pulmonary venous pressure.

Factors Associated with Left Ventricular Function Recovery in Patients with Atrial Fibrillation Related Cardiomyopathy

BACKGROUND

The diagnosis of atrial fibrillation (AFIB) related cardiomyopathy relies on ruling out other causes for heart failure and on recovery of left ventricular (LV) function following return to sinus rhythm (SR). The pathophysiology underlying this pathology is multifactorial and not as completely known as the factors associated with functional recovery following the restoration of SR.

OBJECTIVES

To identify clinical and echocardiographic factors associated with LV systolic function improvement following electrical cardioversion (CV) or after catheter ablation in patients with reduced ejection fraction (EF) related to AFIB and normal LV function at baseline.

METHODS

The study included patients with preserved EF at baseline while in SR whose LVEF had reduced while in AFIB and improved LVEF following CV. We compared patients who had improved LVEF to normal baseline to those who did not.

RESULTS

Eighty-six patients with AFIB had evidence of reduced LV systolic function and improved EF following return to SR. Fifty-five (64%) returned their EF to baseline. Patients with a history of ischemic heart disease (IHD), worse LV function, and larger LV size during AFIB were less likely to return to normal LV function. Multivariant analysis revealed that younger patients with slower ventricular response, a history of IHD, larger LV size, and more significant deterioration of LVEF during AFIB were less likely to recover their EF to baseline values.

CONCLUSIONS

Patients with worse LV function and larger left ventricle during AFIB are less likely to return their baseline LV function following the restoration of sinus rhythm.

Left atrial function by cardiac computed tomography is a predictor of heart failure and cardiovascular death

OBJECTIVES

We sought to evaluate cardiac CT angiography (CCTA)-based assessment of left atrial (LA) function as a predictor of hospitalizations for heart failure (HF) and cardiovascular (CV) mortality.

METHODS

LA function was evaluated using automatic derivation of LA volumes to calculate LA total emptying fraction (LATEF) in 788 consecutive patients with normal sinus rhythm who had undergone spiral CT scans. The relationship between LATEF evaluated by CCTA and the composite endpoint of admission for HF or CV mortality was analyzed using Cox models.

RESULTS

During a median follow-up of 4 years, there were 100 events, 62 HF hospitalizations, and 38 cardiovascular deaths. Mean LATEF was 30.7 ± 10.7% and 40.5 ± 11.2% in patients with and without events, respectively (p < 0.0001). A high LATEF (upper tertile > 46%) was associated with a very low event rate (3.5% at 6 years [95% CI 1.7-7.1%]). The adjusted HR for HF or CV mortality was 4.37 (95% CI 1.99-9.60) in the lowest LATEF tertile, and 2.29 (95% CI 1.03-5.14) in the middle tertile, relative to the highest tertile. For the endpoint of HF alone, adjusted HR for the lowest LATEF tertile was 5.93 (95% CI 2.23-15.82) and for the middle tertile 2.89 (95% CI 1.06-7.86). The association of LATEF with outcome was similar for patients with both reduced and preserved left ventricular (LV) ejection fraction (P_interaction = 0.724). Reduced LATEF was associated with a high event rate, even when coupled with normal LA volume.

CONCLUSION

CCTA-derived LA function is a predictor of HF hospitalization or CV death, independent of clinical risk factors, LA volume, and LV systolic function.

KEY POINTS

• Left atrial function can be automatically derived from cardiac CTA scans. • Cardiac CTA-derived left atrial function is a predictor of hospitalization for heart failure and cardiovascular death. • Evaluation of left atrial function could be useful in identifying patients at risk of heart failure.

44 Determinants of functional tricuspid regurgitation progression

Background

Tricuspid regurgitation has been the focus of increasing interest and research in recent years. However, few data are available with regard to risk factors associated with the evolution of TR.

purpose

The aimed to determine the risk factors for the development of hemodynamically significant functional TR.

Methods

We studied 1552 subjects with an index echocardiogram demonstrating trivial or mild TR. Risk factors for TR progression to moderate or severe TR during a median follow-up time of 38 months (IQR 26 to 63 months), were determined using logistic regression.

Results

In the multivariable logistic regression model, older age, female gender, pacemaker electrode and indicators of left heart disease (LA enlargement, increased pulmonary artery pressure (PAP), atrial fibrillation, and left-sided valvular disease) were associated with future development moderate or severe TR (Table). The strongest predictors of TR progression were PAP, LA size, AF, and age.

The final echocardiographic examination demonstrated a marked worsening in the severity of left-sided myocardial and valvular disease, that was more prominent in subjects with TR progression (Figure). Compared with subjects in whom TR did not progress, subjects with TR progression demonstrated an increase in PAP and in the severity of mitral and aortic valve disease, larger increases in LA and reductions in LVEF (Figure). Lager proportions of subjects progressing to significant TR developed AF, were implanted with pacemakers or defibrillators or underwent valvular interventions (Figure). The mean PAP change between the baseline and final echocardiographic examination was 16 ± 15 mm Hg and 3 ± 11 mm Hg with and without TR progression, respectively (P &lt; 0.0001).

Conclusion

Predictors of TR progression are mostly indicators of more advanced left heart disease. In addition, progression to significant TR is associated with a more acceleration course of left hear disease.

Independent Predictors of TR Progression Characteristics HR (95% CI) P value Age (per 10 years increase) 1.35 (1.31-1.50) &lt;0.0001 Female sex 1.50 (1.13-1.99) &lt;0.0001 Heart failure 2.76 (1.43-5.32) 0.002 LA enlargement ≥ Moderate 1.86 (1.29-2.67) 0.001 Atrial fibrillation 2.34 (1.57-3.49) &lt;0.0001 Pacemaker/ICD 2.93 (1.48-5.78) 0.002 Pulmonary artery pressure (per 10 mm Hg increase) 1.47 (1.29-1.69) &lt;0.0001 Valvular heart disease≥ Moderate 1.50 (1.11-2.04) 0.009

Abstract 44 Figure. Proportion of new abnormalities

40 Long-term clinical outcome of functional tricuspid regurgitation

Background

Significant functional tricuspid regurgitation (TR) has been associated with higher risk for adverse cardiovascular outcomes. Left-sided heart disease (LHD) is a potentially important confounder of this association because it is strongly linked to both TR and to clinical outcome.

Methods

We studied 5886 patients who were followed for a period of 10-years after the index echocardiographic examination. The relationship between TR severity and the composite endpoint of admission for heart failure or cardiovascular mortality was analyzed using a Cox model. An additional analysis included a propensity-score-matching. To simplify the modeling of the severity of LHD, we calculated an additive score summing the number of LHD components as follows: reduced LVEF, LA enlargement ≥moderate, aortic or mitral valve disease (regurgitation or stenosis ≥moderate) and PASP≥50 mmHg.

Results

Higher TR grade was associated with markers of LHD including left ventricular systolic dysfunction, valvular heart disease ≥moderate, left atrial enlargement and pulmonary hypertension (All P &lt; 0.001). There was a significant interaction between TR and the presence of LHD with regard to the endpoint of heart failure in the model for admission for heart failure (P = 0.01) and the combined endpoint of heart failure and cardiovascular mortality (P = 0.02). In both models, moderate/severe TR was associated with higher risk for heart failure (hazard ratio [HR] 3.13; 95% CI 2.49–3.93, P &lt; 0.0001) and the combined endpoint of heart failure or cardiovascular mortality (HR 2.61; 95% CI 1.33–5.13, P = 0.005) only in patients without LHD. The interaction plot (Figure) demonstrates that when LHD is present, TR is not a predictor of clinical outcome.

Propensity score matching yielded 350 patient pairs, of which 88% had LHD. The HR for heart failure or cardiovascular mortality at 10-years was 0.78 (95% CI 0.56–1.08, P = 0.14) in the moderate/severe TR as compared with the trivial/mild TR.

Conclusions

Moderate or severe functional TR portends an increased risk for heart failure and cardiovascular mortality only when isolated, without concomitant LHD.

Abstract 40 Figure. Interaction plot

Risk Score for Prediction of 10-Year Atrial Fibrillation: A Community-Based Study

Purpose We used a large real-world data from community settings to develop and validate a 10-year risk score for new-onset atrial fibrillation (AF) and calculate its net benefit performance.

Methods Multivariable Cox proportional hazards model was used to estimate effects of risk factors in the derivation cohort (n = 96,778) and to derive a risk equation. Measures of calibration and discrimination were calculated in the validation cohort (n = 48,404).

Results Cumulative AF incidence rates for both the derivation and validation cohorts were 5.8% at 10 years. The final models included the following variables: age, sex, body mass index, history of treated hypertension, systolic blood pressure ≥ 160 mm Hg, chronic lung disease, history of myocardial infarction, history of peripheral arterial disease, heart failure and history of an inflammatory disease. There was a 27-fold difference (1.0% vs. 27.2%) in AF risk between the lowest (–1) and the highest (9) sum score. The c-statistic was 0.743 (95% confidence interval [CI], 0.737–0.749) for the derivation cohort and 0.749 (95% CI, 0.741–0.759) in the validation cohort. The risk equation was well calibrated, with predicted risks closely matching observed risks. Decision curve analysis displayed consistent positive net benefit of using the AF risk score for decision thresholds between 1 and 25% 10-year AF risk.

Conclusion We provide a simple score for the prediction of 10-year risk for AF. The score can be used to select patients at highest risk for treatments of modifiable risk factors, monitoring for sub-clinical AF detection or for clinical trials of primary prevention of AF.

Longitudinal two-dimensional strain for the diagnosis of left ventricular segmental dysfunction in patients with acute myocardial infarction

The objectives of this study were to assess whether 2-dimensional strain (2DS) can detect left ventricular (LV) segmental dysfunction and to compare the diagnostic accuracy of various 2DS parameters. Multiple segmental longitudinal 2DS parameters were measured in 54 patients with a first myocardial infarction and single vessel coronary artery disease (age: 56 ± 11 years, 74% men, LV ejection fraction: 47 ± 10%, left anterior descending artery occlusion in 63%) and 14 age-matched subjects. 2DS parameters were compared to visual assessment of segmental function by multiple observers. Using receiver-operating characteristics analysis, the area under the curve (AUC) for peak systolic strain in diagnosing segmental dysfunction (akinetic or hypokinetic LV segments) and for diagnosing akinetic segments was 0.85 (95% confidence interval 0.83-0.88) and 0.88 (0.85-0.90), respectively (all P values < 0.001). Other 2DS strain parameters had similar (peak strain, peak strain rate) or lower (post-systolic shortening, time-to-peak strain, diastolic 2DS parameters) AUC values. An absolute value of peak systolic strain <16.8% (25th percentile in normal subjects) had high sensitivity (0.89) and negative predictive values (0.88), but low specificity (0.55) and positive predictive values (0.59) for diagnosing segmental dysfunction. Similar findings were observed using a cutoff of <13.3% (absolute value of 10th percentile) for diagnosing akinetic segments. Diagnostic accuracy was significantly worse for segments in which visual segmental assessment was discordant between observers. In conclusion, 2DS can be used to diagnose segmental LV dysfunction with high sensitivity but limited specificity. The diagnostic limitation of 2DS is partially related to the visual echocardiographic definition of segmental abnormality.

Time Dependence of the Effect of Right Ventricular Dysfunction on Clinical Outcomes After Myocardial Infarction: Role of Pulmonary Hypertension

Background

The clinical importance of right ventricular (RV) function in acute myocardial infarction is well recognized, but the impact of concomitant pulmonary hypertension (PH) has not been studied.

Methods and Results

We studied 1044 patients with acute myocardial infarction. Patients were classified into 4 groups according to the presence or absence of RV dysfunction and PH, defined as pulmonary artery systolic pressure >35 mm Hg: normal right ventricle without PH (n=509), normal right ventricle and PH (n=373), RV dysfunction without PH (n=64), and RV dysfunction and PH (n=98). A landmark analysis of early (admission to 30 days) and late (31 days to 8 years) mortality and readmission for heart failure was performed. In the first 30 days, RV dysfunction without PH was associated with a high mortality risk (adjusted hazard ratio 5.56, 95% CI 2.05–15.09, P<0.0001 compared with normal RV and no PH). In contrast, after 30 days, mortality rates among patients with RV dysfunction were increased only when PH was also present. Compared with patients having neither RV dysfunction nor PH, the adjusted hazard ratio for mortality was 1.44 (95% CI 0.68–3.04, P=0.34) in RV dysfunction without PH and 2.52 (95% CI 1.64–3.87, P<0.0001) in RV dysfunction with PH. PH with or without RV dysfunction was associated with increased risk for heart failure.

Conclusion

In the absence of elevated pulmonary pressures, the risk associated with RV dysfunction after acute myocardial infarction is entirely confined to the first 30 days. Beyond 30 days, PH is the stronger risk factor for long‐term mortality and readmission for heart failure.

Assessment of left sided filling dynamics in diastolic dysfunction using cardiac computed tomography

BACKGROUND

Left ventricular (LV) diastolic dysfunction (DD) often accompanies coronary artery disease but is difficult to assess since it involves a complex interaction between LV filling and left atrial (LA) emptying.

OBJECTIVE

To characterize simultaneous changes in LA and LV volumes using cardiac computed tomography (CT) in a group of patients with various grades of DD based on echocardiography.

METHODS

We identified 35 patients with DD by echocardiography, who had also undergone cardiac CT, and 35 age-matched normal controls. LV and LA volumes were measured every 10% of the RR interval, using semi-automatic software. From these, - systolic, early-diastolic and late-diastolic volume changes were calculated, and additional parameters of diastolic filling derived. Conduit volume was defined as the difference between the LV and LA early-diastolic volume change.

RESULTS

Patients with DD had significantly larger LV mass, and LA volumes, reduced early emptying volumes and increased conduit volume as percent of early LV filling (All p<0.001). LA function, manifesting as total emptying fraction (LATEF), decreased proportionately with worsening grades of DD (p<0.001). LA contractile function was maintained until advanced grade-3 DD. By receiver operating characteristic analysis, LATEF had an AUC of 0.88 to separate between normals and DD. At a threshold of <42.5%, LATEF has 97% sensitivity and 69% specificity to detect DD.

CONCLUSIONS

DD is characterized by reduced LA function and an alteration in the relative contributions of the atrial emptying and conduit volume components of early LV filling. In patients undergoing cardiac CT, it is possible to identify the presence and severity of DD.

Symptoms in severe aortic stenosis are associated with decreased compensatory circumferential myocardial mechanics

BACKGROUND

Symptomatic patients with severe aortic stenosis (AS) demonstrate abnormal left ventricular (LV) mechanics. The aim of this study was to compare mechanics in asymptomatic and symptomatic patients with severe AS using two-dimensional myocardial strain imaging.

METHODS

One hundred fifty-four patients with severe AS (aortic valve area ≤ 1.0 cm(2)) referred to a heart valve clinic from 2004 to 2011 were studied. Thirty patients were asymptomatic, with normal LV ejection fractions (≥ 55%), without other significant valvular disease or wall motion abnormalities. Thirty-two symptomatic patients who underwent early aortic valve replacement, with similar age, gender, LV ejection fraction, and aortic valve area, were selected for comparison. Both groups were also compared with 32 healthy subjects with similar age and gender distributions and normal echocardiographic results who served as controls. LV longitudinal and circumferential strain and rotation were measured using speckle-tracking software applied to archived echocardiographic studies. Conventional echocardiographic and myocardial mechanical parameters were compared among the study subgroups.

RESULTS

Patients with asymptomatic severe AS demonstrated smaller reductions in longitudinal strain, higher (supernormal) apical circumferential strain (-38 ± 6% vs -35 ± 4%, P < .05), and extreme (supernormal) apical rotation (12.2 ± 4.9° vs 2.9 ± 1.7°, P < .0005) compared with symptomatic patients. Apical rotation < 6° was the single significant predictor of symptoms in logistic regression analysis of clinical, echocardiographic, and mechanical parameters. Twelve asymptomatic patients underwent eventual aortic valve replacement and showed decreases in strain and apical rotation compared with baseline values.

CONCLUSIONS

Longitudinal strain was uniformly low in patients with severe AS and lower in those with symptoms. Compensatory circumferential myocardial mechanics (increased apical circumferential strain and rotation) were absent in symptomatic patients. Thus, myocardial mechanics may help in the follow-up of patients with severe AS and timing of valve surgery.

Pulmonary hypertension, right ventricular function, and clinical outcome in acute decompensated heart failure

BACKGROUND

Pulmonary hypertension (PH) and right ventricular (RV) dysfunction have been associated with adverse outcome in patients with chronic heart failure. However, data are lacking in the setting of acute decompensated heart failure (ADHF). We sought to determine prognostic significance of PH in patients with ADHF and its interaction with RV function.

METHODS

We studied 326 patients with ADHF. Pulmonary artery systolic pressure (PASP) and RV function were determined with the use of Doppler echocardiography, with PH defined as PASP >50 mm Hg. The primary end point was all-cause mortality during 1-year follow-up.

RESULTS

PH was present in 139 patients (42.6%) and RV dysfunction in 83 (25.5%). The majority of patients (70%) with RV dysfunction had PH. Compared with patients with normal RV function and without PH, the adjusted hazard ratio (HR) for mortality was 2.41 (95% confidence interval [CI] 1.44-4.03; P = .001) in patients with both RV dysfunction and PH. Patients with normal RV function and PH had an intermediate risk (adjusted HR 1.78, 95% CI 1.11-2.86; P = .016). Notably, patients with RV dysfunction without PH were not at increased risk for 1-year mortality (HR 1.04, 95% CI 0.43-2.41; P = .94). PH and RV function data resulted in a net reclassification improvement of 22.25% (95% CI 7.2%-37.8%; P = .004).

CONCLUSIONS

PH and RV function provide incremental prognostic information in ADHF. The combination of PH and RV dysfunction is particularly ominous. Thus, the estimation of PASP may be warranted in the standard assessment of ADHF.

Restrictive left ventricular filling pattern and risk of new-onset atrial fibrillation after acute myocardial infarction

Mechanisms for atrial arrhythmias that occur in the context of acute myocardial infarction (AMI) have not been well characterized. AMI often leads to alterations in left ventricular (LV) filling dynamics, which may result in advanced diastolic dysfunction. Diastolic dysfunction may produce increased left atrial (LA) pressure and initiate LA remodeling, promoting the progression to atrial fibrillation (AF). We studied 1,169 patients admitted with AMI. Advanced diastolic dysfunction was defined as a restrictive filling pattern (RFP), defined as ratio of early to late transmitral velocity of mitral inflow >1.5 or deceleration time <130 ms. The relation between RFP and the primary end point of new-onset AF occurring within 6 months was analyzed using multivariable Cox models. Of 1,169 patients (70% men, mean ± SD 64 ± 10 years of age), 110 (9.4%) developed new-onset AF (19.6% and 7.5% in patients with and without RFP, respectively, p <0.0001). RFP was associated with a hazard ratio of 2.72 for AF (95% confidence interval 1.83 to 4.05, p <0.0001). After multivariable adjustments for clinical variables, LV ejection fraction (EF) and LA size, RFP remained an independent predictor of AF (hazard ratio 2.17, 95% confidence interval 1.42 to 3.32, p <0.0001). Risk of AF was higher in patients with RFP for preserved (≥45%, hazard ratio 2.14, 95% confidence interval 1.09 to 4.20, p = 0.03) or decreased (hazard ratio 2.80, 95% confidence interval 1.63 to 4.82, p <0.0001) LVEF. In contrast, decreased LVEF in the absence of RFP was similar to that of patients with preserved LVEF and without RFP. In conclusion, in patients with AMI, presence of advanced diastolic dysfunction was independently associated with new-onset AF, suggesting that increased filling pressures may contribute to the development of AF after AMI.

Relation of myocardial mechanics in severe aortic stenosis to left ventricular ejection fraction and response to aortic valve replacement

Decreased left ventricular (LV) longitudinal strain and increased circumferential LV strain have been demonstrated in patients with severe aortic stenosis (AS) and normal LV ejection fraction (LVEF). Biplane myocardial mechanics normalize after aortic valve replacement (AVR). This study objective was to examine LV mechanics before and soon after AVR in patients with AS and LV systolic dysfunction. Paired echocardiographic studies before and soon (7 ± 3 days) after AVR were analyzed in 64 patients with severe AS: 32 with normal LVEF (≥ 50%), 16 with mild to moderate LV dysfunction (LVEF <36% to 50%), and 16 with severe LV dysfunction (LVEF ≤ 35%). Longitudinal myocardial function was assessed from 3 apical views (average of 18 segments) and circumferential function was assessed at mid-LV and apical levels (average of 6 segments per view). Strain, strain rate, and mid-LV and apical rotations were measured using 2-dimensional velocity vector imaging. Before AVR (1) longitudinal strain was low in all patients and correlated with LVEF (ρ = 0.74, p <0.001), (2) mid-LV circumferential strain was supranormal in patients with normal LVEF and low in patients with low LVEF (ρ = 0.88, p <0.001), and (3) apical rotation was highest in patients with mild to moderate LV dysfunction. After AVR, LVEF increased in patients with LV dysfunction and myocardial mechanics partly normalized. In conclusion, compensatory mechanisms (high circumferential strain in patients with preserved LVEF and increased apical rotation in patients with mild to moderate LV dysfunction) were observed in patients with severe AS. Compensatory mechanics were lost in patients with severe LV dysfunction. AVR partly reversed these changes in patients with LV dysfunction.

Frequency, characteristics, and outcome of patients with aortic stenosis, left ventricular dysfunction, and high (versus low) trans-aortic pressure gradient

BACKGROUND

Trans-aortic pressure gradient in patients with aortic stenosis and left ventricular systolic dysfunction is typically low but occasionally high.

OBJECTIVES

To examine the distribution of trans-aortic PG in patients with severe AS and severe LV dysfunction and compare the clinical and echocardiographic characteristics and outcome of patients with high versus low PG.

METHODS

Using the echocardiographic laboratory database at our institution, 72 patients with severe AS (aortic valve area < or = 1.0 cm2) and severe LV dysfunction (LV ejection fraction < or = 30%) were identified. The characteristics and outcome of these patients were compared.

RESULTS

PG was high (mean PG > or = 35 mmHg) in 32 patients (44.4%) and low (< 35 mmHg) in 40 (55.6%). Aortic valve area was slightly smaller in patients with high PG (0.63 + 0.15 vs. 0.75 +/- 0.16 cm2 in patients with low PG, P = 0.003), and LV ejection fraction was slightly higher in patients with high PG (26 +/- 5 vs. 22 +/- 5% in patients with low PG, P = 0.005). During a median follow-up period of 9 months 14 patients (19%) underwent aortic valve replacement and 46 patients (64%) died. Aortic valve replacement was associated with lower mortality (age and gender-adjusted hazard ratio 0.19, 95% confidence interval 0.05-0.82), whereas trans-aortic PG was not (P = 0.41).

CONCLUSIONS

A large proportion of patients with severe AS have relatively high trans-aortic PG despite severe LV dysfunction, a finding partially related to more severe AS and better LV function. Trans-aortic PG is not related to outcome in these patients.

Impact of diastolic dysfunction on the development of heart failure in diabetic patients after acute myocardial infarction

BACKGROUND

Diabetes is often associated with an abnormal diastolic function. However, there are no data regarding the contribution of diastolic dysfunction to the development of heart failure (HF) in diabetic patients after acute myocardial infarction.

METHODS AND RESULTS

A total of 1513 patients with acute myocardial infarction (417 diabetic) underwent echocardiographic examination during the index hospitalization. Severe diastolic dysfunction was defined as a restrictive filling pattern (RFP) based on E/A ratio >1.5 or deceleration time <130 ms. The primary end points of the study were readmission for HF and all-cause mortality. The frequency of RFP was higher in patients with diabetes (20 versus 14%; P=0.005). During a median follow-up of 17 months (range, 8 to 39 months), 52 (12.5%) and 62 (5.7%) HF events occurred in patients with and without diabetes, respectively (P<0.001). There was a significant interaction between diabetes and RFP (P=0.04) such that HF events among diabetic patients occurred mainly in those with RFP. The adjusted hazard ratio for HF was 2.77 (95%, CI 1.41 to 5.46) in diabetic patients with RFP and 1.21 (95% CI, 0.75 to 1.55) in diabetic patients without RFP. A borderline interaction (P=0.059) was present with regard to mortality (adjusted hazard ratio, 3.39 [95% CI, 1.57 to 7.34] versus 1.61 [95% CI, 1.04 to 2.51] in diabetic patients with and without RFP, respectively).

CONCLUSIONS

Severe diastolic dysfunction is more common among diabetic patients after acute myocardial infarction and portends adverse outcome. HF and mortality in diabetic patients occur predominantly in those with concomitant RFP.

Differential effects of afterload on left ventricular long- and short-axis function: insights from a clinical model of patients with aortic valve stenosis undergoing aortic valve replacement

BACKGROUND

The effects of left ventricular (LV) afterload on longitudinal versus circumferential ventricular mechanics are largely unknown. Our objective was to examine changes in LV deformation before and early after aortic valve replacement (AVR) in patients with severe aortic valve stenosis (AS).

METHODS

Paired echocardiographic studies before and early (7 +/- 3 days) after AVR were analyzed in 45 patients (age 67 +/- 12 years, 49% men) with severe AS and normal LV ejection fraction without segmental wall motion abnormalities. Longitudinal myocardial function was assessed from 3 apical views (average of 18 segments). Circumferential function was assessed at mid and apical levels (averaging 6 segments per view). Strain, strain rate (SR), and LV twist (relative rotation of the mid and apex) were measured using 2-dimensional strain software.

RESULTS

Early post-AVR, (1) LV size and LV ejection fraction did not change; (2) longitudinal systolic strain, which was lower than normal before AVR, increased (-12.8 +/- 1.7 to -15.9 +/- 2.2, P < .05), whereas mid-LV circumferential strain, which was higher than normal, decreased (-27.0 +/- 5.1 to -22.3 +/- 4.9, P < .05); (3) longitudinal early diastolic SR increased (0.6 +/- 0.1 to 0.7 +/- 0.2, P < .05), whereas mid-LV circumferential diastolic SR decreased (1.2 +/- 0.5 to 1.0 +/- 0.3, P < .05); and (4) LV twist increased (3.7 degrees +/- 2.1 degrees to 6.1 degrees +/- 2.9 degrees , P < .05).

CONCLUSIONS

Aortic valve stenosis causes differential changes in longitudinal and circumferential mechanics that partially normalize after AVR. These findings provide new insights into the mechanical adaptation of the LV to chronic afterload elevation and its response to unloading.

Relation of statin therapy to risk of heart failure after acute myocardial infarction

Recent studies suggest that statin therapy reduces hospitalizations for heart failure (HF). However, few data exist regarding the role of statins in preventing HF after acute myocardial infarction (AMI). In addition, the potential impact of left ventricular (LV) ejection fraction (EF) and coexisting functional mitral regurgitation (MR) on the efficacy of statin therapy was not considered. We prospectively studied 1,563 patients with AMI. The primary endpoint was readmission for the treatment of HF. The effect of statin therapy initiated before hospital discharge was evaluated using a Cox model, adjusting for clinical variables, a propensity score for statin therapy, LVEF, and MR grade. Patients with recurrent infarctions were censored. Statins were prescribed in 1,048 patients (67.1%) before hospital discharge. During a median follow-up of 17 months, admissions for HF were lower in patients receiving statins (6.5% vs 14.8%; unadjusted hazard ratio 0.45, 95% confidence interval 0.32 to 0.63, p <0.0001). In a multivariable Cox model, statin therapy was associated with a significant reduction of hospitalization for HF (HR 0.62, 95% confidence interval 0.43 to 0.89, p = 0.009). There was a significant interaction between MR and statin therapy (p = 0.039), such that the beneficial effect of statins on HF hospitalizations was most pronounced in patients without concomitant MR and absent in patients with hemodynamically significant MR. In conclusion, in patients with AMI statin therapy initiated before hospital discharge significantly reduces subsequent hospitalizations for HF. The effect of statins is driven largely by the reduction in events in patients without concomitant hemodynamically significant MR.

Predictive value of white blood cell subtypes for long-term outcome following myocardial infarction

INTRODUCTION

Elevation of total white blood cells (WBC) count is associated with higher mortality in patients with acute coronary syndromes. However, it is unknown which specific subset of leukocytes best correlates with increased risk of adverse outcome.

METHODS AND RESULTS

We prospectively studied the predictive value of WBC subtypes for long-term outcome in 1037 patients with acute myocardial infarction (AMI). Total WBC, neutrophil, monocyte and lymphocyte counts, and high-sensitivity C-reactive protein (CRP) were obtained in each patient. The median duration of follow up was 23 months (range, 6-42 months). Analyzed separately, baseline total WBC (HR 2.2, 95% CI 1.5-3.3; P<0.0001), neutrophil (HR 2.7, 95% CI 1.8-4.1; P<0.0001) and monocyte (HR 1.9, 95% CI 1.3-2.8; P=0.001) counts in the upper quartile, and lymphocyte count in the lower quartile (HR 1.5, 95% CI 1.1-2.3; P=0.03), were all independent predictors of mortality. Comparing nested models, adding other WBC data failed to improve model based on neutrophil count. In contrast, adding neutrophil count to the models based on total WBC (P=0.01), on monocyte count (P<0.0001) or on lymphocyte count (P<0.0001) improved the prediction of the models. Neutrophil count in the upper quartile (>or=9800 microL(-1)) remained a strong independent predictor of mortality after adjustment for left ventricular systolic function and for CRP (HR 2.2, 95% CI 1.6-3.0; P<0.0001).

CONCLUSION

Of all WBC subtypes, elevated neutrophil count best correlates with mortality in patients with AMI. Neutrophil count provides additive prognostic information when combined with CRP.

Diagnostic accuracy of myocardial hypoenhancement on multidetector computed tomography in identifying myocardial infarction in patients admitted with acute chest pain syndrome

OBJECTIVE

To evaluate prevalence and diagnostic accuracy of myocardial hypoenhancement (MH) using multidetector computed tomography (MDCT) in patients admitted for acute chest pain syndromes.

METHODS

Sixty-nine patients underwent first-pass MDCT, coronary angiography, and echocardiography. Using a standardized analysis protocol, left ventricular short-axis reformations were evaluated for presence, size, and density of MH in 16 myocardial segments. These were correlated with the presence and location of myocardial infarction (MI), regional myocardial dysfunction, and coronary artery disease.

RESULTS

Myocardial hypoenhancement was found in acute MI (27/35), healed MI (6/14), unstable angina (3/9), and atypical chest pain (0/11). Sensitivity, specificity, and positive and negative predictive values of MH for diagnosing any MI were 67%, 85%, 92% and 52%, respectively.

CONCLUSIONS

The presence of MH on MDCT in acute chest pain patients has high positive predictive value and specificity but only moderate sensitivity for presence of acute or healed MI using the strict criteria proposed in this study.

Is functional improvement after myocardial infarction predicted with myocardial enhancement patterns at multidetector CT?

PURPOSE

To prospectively evaluate the sensitivity of myocardial early perfusion defects (EDs) and late enhancement (LE) at multidetector computed tomography (CT) following acute myocardial infarction (AMI) to predict segment myocardial dysfunction and myocardial functional recovery (MFR), by using echocardiography as the reference standard.

MATERIALS AND METHODS

Institutional review board approval and informed consent were obtained. Twenty-six patients (25 men, one woman; mean age, 53 years+/-9 [standard deviation]), underwent baseline multidetector CT, coronary angiography, and echocardiography within a week of AMI and a follow-up echocardiography at 3 months. ED, LE, and late hypoattenuation were compared with regional left ventricular function and MFR. A logistic regression model and generalized estimating equation analysis were applied to estimate the predictive effect of ED and LE. Differences between groups were evaluated by using nonpaired Student t tests.

RESULTS

All EDs and LE corresponded with AMI location determined by using angiography and echocardiography. For occluded arteries (n=5), no relationship was found between the presence of ED or LE and MFR. For patent arteries (n=21), presence of LE had a respective sensitivity and specificity of 73% and 85% for predicting follow-up segment dysfunction, compared with 57% and 90% for ED. In abnormal baseline segments, nonrecovery was clearly related to the presence and size of segment defect area for both ED (odds ratio: 1.95 [95% confidence interval: 0.9, 4.1] per square centimeter) and LE (odds ratio: 1.85 [95% confidence interval: 1.2, 2.9] per square centimeter). Segments that recovered had significantly lower prevalence of ED and LE, and if present, were significantly smaller than in segments remaining abnormal (P<.05).

CONCLUSION

The presence and size of ED and LE at multidetector CT is closely related to follow-up segment myocardial dysfunction and MFR.

Echocardiography-based Spectrum of Severe Tricuspid Regurgitation: The Frequency of Apparently Idiopathic Tricuspid Regurgitation

BACKGROUND

The cause of tricuspid valve (TV) regurgitation (TR) occasionally remains unclear. The objectives of our study were to define the causal spectrum of severe TR diagnosed by echocardiography at a tertiary medical center and to assess the relative frequency and determine the clinical and echocardiographic characteristics of TR without an apparent cause (idiopathic TR).

METHODS

Consecutive patients with severe TR were identified by the echocardiography laboratory computerized database. The echocardiographic reports of all patients were reviewed and the causes of TR were determined. The echocardiographic studies and medical charts were reviewed in patients without an obvious cause of TR.

RESULTS

Of 242 consecutive patients diagnosed with severe TR, organic TV disease was evident in 23 patients (9.5%) and significant pulmonary hypertension (estimated pulmonary artery systolic pressure > 50 mm Hg) in an additional 157 patients (64.9%). After further excluding patients with various confounding factors, possibly associated with occult organic TV disease or significant pulmonary hypertension, 23 patients (9.5%) had severe TR without an apparent cause. Of these, TV coaptation appeared relatively intact, allowing adequate estimation of pulmonary artery pressure, in 15 patients (6.2% of all patients with severe TR; idiopathic TR group). Patients with idiopathic TR were older (76 +/- 10 years), with a high frequency of atrial fibrillation (93%), and prominent TV annular dilatation.

CONCLUSIONS

After excluding multiple potential causes of TR, severe TR is occasionally idiopathic. Annular dilatation (secondary to aging, atrial fibrillation, or other causes) is the likely mechanism of TR in these patients.

Ischemic Mitral Regurgitation and Risk of Heart Failure After Myocardial Infarction

BACKGROUND

The development of ischemic mitral regurgitation (MR) after myocardial infarction may impose hemodynamic load during a period of active left ventricular remodeling and promote heart failure (HF). However, few data are available on the relationship between ischemic MR and the long-term risk for HF.

METHODS

We prospectively studied 1190 patients admitted for acute myocardial infarction. Mitral regurgitation was assessed by echocardiography and was considered mild, moderate, and severe when the regurgitant jet area occupied less than 20%, 20% to 40%, and greater than 40% of the left atrial area, respectively. The median duration of follow-up was 24 months (range, 6-48 months).

RESULTS

Mild and moderate or severe ischemic MR was present in 39.7% and 6.3% of patients, respectively. After adjusting for ejection fraction and clinical variables (age, sex, Killip class, previous infarction, hypertension, diabetes mellitus, anterior infarction, ST-elevation infarction, and coronary revascularization), compared with patients without MR, the hazard ratios for HF were 2.8 (95% confidence interval [CI], 1.8-4.2; P<.001) and 3.6 (95% CI, 2.0-6.4; P<.001) in patients with mild and moderate or severe ischemic MR, respectively. The adjusted hazard ratios for death were 1.2 (95% CI, 0.8-1.8; P = .43) and 2.0 (95% CI, 1.2-3.4; P = .02) in patients with mild and moderate or severe MR, respectively.

CONCLUSIONS

There is a graded independent association between the severity of ischemic MR and the development of HF after myocardial infarction. Even mild ischemic MR is associated with an increase in the risk of HF.

Comparison of multidetector computed tomography versus echocardiography for assessing regional left ventricular function

Multidetector computed tomography (MDCT) of the heart is a rapidly developing technique mainly used to evaluate the coronary arteries. However, it is also capable of evaluating ventricular function. It compares well with magnetic resonance imaging in calculating volumes and ejection fractions, but little has been reported on its ability to assess left ventricular (LV) segmental wall motion (LVSWM). This study compared semiquantitative LVSWM scoring by MDCT with echocardiography as the gold standard. Thirty-nine patients underwent MDCT angiography on a 16-slice scanner. Short- and long-axis LV slices were created at different phases of the cardiac cycle and visually evaluated using cine mode. Echocardiography was performed <48 hours after MDCT for 21 patients after acute myocardial infarctions and <1 month after MDCT for 18 patients without acute myocardial infarctions. Two blinded observers scored the MDCT and echocardiographic examinations according to the 16-segment model, scoring each segment from 1 (normal) to 3 (akinetic). Segmental dysfunction was found in 27 patients by echocardiography and in 24 by MDCT. An identical score was given by the 2 methods in 502 of 616 assessable segments (82%). Using a binary analysis (normal or abnormal), there was 89% agreement (546 of 616 segments). MDCT had a sensitivity of 66% (103 of 155 segments) and a specificity of 96% (443 of 461 segments) compared with echocardiography as the gold standard. Most disagreements occurred in the right coronary artery segments. In conclusion, MDCT can be used to evaluate LVSWM, showing good agreement with echocardiography, except for the right coronary artery segments.

Global longitudinal strain: a novel index of left ventricular systolic function

BACKGROUND

Echocardiographic estimation of global left ventricular (LV) function is subjective and time consuming. Our aim was to develop a novel approach for assessment of global LV function from 2-dimensional echocardiographic images

METHODS

Novel computer software for tissue tracking was developed and applied as follows: digital loops were acquired from apical 2-, 3-, and 4-chamber views and a line was loosely traced along the LV endocardium at the frame wherein it was best defined. Around this line, the software selected natural acoustic markers moving with the tissue. Automatic frame-by-frame tracking of these markers during the heart cycle yielded a measure of contractility along the selected region of interest. Global longitudinal strain (GLS) and GLS rate (GLSR) were calculated for the entire U-shaped length of LV myocardium (basal, mid, and apical segments of 2 opposite walls in each view). To test this software, computer-derived GLS and GLSR were analyzed by a nonechocardiographer, blinded to the echocardiographic interpretation, in 27 consecutive patients after myocardial infarction (MI) (age 64.4 +/- 12.9 years; 19 men; mean wall-motion score index of 1.79 +/- 0.44) and compared with those obtained in 12 consecutive control patients (age 59.0 +/- 9.7 years; 8 women), with a normal echocardiographic study.

RESULTS

GLS and GLSR, averaged from the 3 apical views, differed significantly in patients post-MI compared with control patients (GLS -14.7 +/- 5.1% vs -24.1 +/- 2.9% and GLSR -0.57 +/- 0.21/s vs -1.02 +/- 0.09/s for patients post-MI vs control patients, respectively; both P <.0001). There was a good linear correlation between the wall-motion score index and the GLS and GLSR (R = 0.68 and R = 0.67, respectively; both P <.0001). A cut-off value for GLS of -21% had 92% sensitivity and 89% specificity and a cut-off value for GLSR -0.9/s had 92% sensitivity and 96% specificity for the detection of patients post-MI.

CONCLUSIONS

GLS and GLSR are novel indices for assessment of global LV function from 2-dimensional echocardiographic images. Early validation studies with the method are suggestive of high sensitivity and specificity in the detection of LV systolic dysfunction in patients post-MI.

Natural history of moderate mitral valve stenosis

BACKGROUND

With the introduction of surgery and percutaneous balloon valvuloplasty for relieving severe mitral stenosis the natural history of the disease has markedly altered.

OBJECTIVES

To determine the natural history of the disease in patients with moderate mitral valve stenosis.

METHODS

Demographic, clinical and echocardiographic data were evaluated in 36 patients with moderate mitral stenosis during a follow-up of 71 +/- 15 months.

RESULTS

The 36 patients comprised 32 women and 4 men with a mean age of 43.7 +/- 12.2 years; 28 were Jewish and 8 were of Arab origin. During follow-up, there was a significant decrease in mitral valve area, with an increase in mean mitral valve gradient and score. Mean loss of mitral valve area was 0.04 +/- 0.11 cm 2/year. No correlation was found between disease progression and age, past mitral valve commissurotomy, baseline mean gradient or mitral valve score. Larger baseline mitral valve area (P = 0.007) and Arab origin (P = 0.03) had an independent correlation to loss of mitral valve area. Fifteen patients (42%) did not demonstrate any loss in mitral valve area during the follow-up period.

CONCLUSIONS

The rate of mitral valve narrowing in patients with moderate mitral stenosis is variable and cannot be predicted by patient's age, past commissurotomy, valve score or gradient. Secondly, larger baseline mitral valve area and Arab origin showed an independent correlation to loss of mitral valve area; and finally, in many patients valve area did not change over a long observation period.

Failure of left ventricular hypertrophy to regress after surgery for aortic valve stenosis

BACKGROUND

Regression of left ventricular (LV) hypertrophy usually follows surgery for aortic stenosis (AS); however, a significant number of ventricles remain hypertrophied. The extent of this phenomenon, the reasons for failure to regress, and its significance are unclear.

METHODS

We investigated 43 patients before and after aortic valve surgery and divided them into two groups: 30 patients with regression of LV hypertrophy (Group A) and 13 patients without regression (Group B). Preoperative echocardiographic measurements, clinical status, and operative factors were compared between the two groups. The patients were followed up for 42 +/- 22 months for the occurrence of hospitalization for congestive heart failure (CHF) or death.

RESULTS

Preoperatively, the two groups were similar except for an excess of patients in New York Heart Association (NYHA) functional Class IV and a greater incidence of old myocardial infarcts in Group B. Postoperatively, Group B patients had larger LVs with decreased systolic function. This was associated with a poor prognosis (23% mortality and 38% CHF vs 0% and 4% for Group A patients, P = 0.0002). Cox regression analysis showed previous myocardial infarction (P < 0.001) and percent mass reduction (P = 0.019) to be independent predictors of CHF or death.

CONCLUSIONS

Successful regression of LV mass is difficult to predict before surgery; however, its absence is related strongly to a poor long-term prognosis.

Non-surgical myocardial reduction in hypertrophic obstructive cardiomyopathy

BACKGROUND

Percutaneous transluminal septal ablation was recently introduced as an alternative to surgical treatment of hypertrophic obstructive cardiomyopathy. In this procedure, alcohol is injected into a proximal septal artery to create a localized myocardial infarction.

OBJECTIVES

To characterize the immediate and medium-term results following PTSMA.

METHODS

Of 13 patients referred for PTSMA, 8 were found suitable for the procedure. Hemodynamic parameters were evaluated prior to and following the procedure, and clinical and echo-Doppler parameters at 2 weeks and 9 months later.

RESULTS

The procedure was technically successful in all patients. Resting left ventricular outflow gradient at rest (by Doppler) fell from 82 +/- 37 to 15 +/- 8 mmHg (P < 0.001) 9 months later. Late post-procedural gradient after the Valsalva maneuver was 2 +/- 24 mmHg. The degree of mitral regurgitation fell from 2.0 +/- 0 to 1.5 +/- 0.5 (P < 0.05). New York Heart Association class for dyspnea improved from 2.8 +/- 0.5 to 1.8 +/- 0.8 (P < 0.01) and Canadian Cardiovascular Society class for angina from 2.0 +/- 1.3 to 1.3 +/- 1.2 (P = 0.08). Complete right bundle branch block developed in six patients, temporary complete atrioventricular block in three, and persistent block requiring permanent pacing in one. No flow in the distal left anterior descending coronary artery (presumably due to spilling of alcohol) was seen in one (with development of a small antero-apical infarction) and ventricular fibrillation 2 hours post-procedure in one. None of the patients died.

CONCLUSION

PTSMA provided a substantial reduction in left ventricular outflow gradient associated with an improvement in symptomatology. Serious complications are not uncommon. Long-term follow-up is unknown.

Prospective study of early atropine use in dobutamine stress echocardiography

AIMS

Dobutamine stress echocardiography is a time-consuming test, often requiring atropine at the end of the protocol to achieve target heart rate (HR). We examined whether earlier administration of atropine in appropriate patients would shorten test time and increase the likelihood of achieving peak HR.

METHODS

Two hundred and seventy consecutive patients were randomized prospectively to conventional or early atropine protocols. Of these, 120 patients with an inadequate HR response [mid-30 microg/kg/min HR<100 (age <50) or <90 (age >50); or mid-40 microg/kg/min stage HR<120 (age <50) or <110 (age >50)] were included in the analysis. The remaining patients were used in a model to define which patients are likely to require atropine.

RESULTS

The 61 patients receiving early-atropine had decreased test-time relative to the 59 not receiving early-atropine (17:05 vs. 18:24 min:sec, P=0.014) accompanied by a 10% reduction in total dobutamine dose (P=0.008). Their HR at end of 40 microg/kg/min was 123+/-18 vs. 105+/-17 respectively, P<0.0001. Only 7% of the early-atropine group failed to reach target HR vs. 15% not receiving early-atropine. By multivariate analysis, age (P<0.0001), HR at end of 30 microg/kg/min stage (P<0.0001), beta-blocker use (P=0.009) and baseline HR (P=0.04) were predictors of need for atropine.

CONCLUSION

Giving atropine early in appropriate patients can reduce test times without an increase in side effects. Our model enables accurate prediction of these patients.