Prediction of Cardiovascular Outcomes With Left Atrial Size

OBJECTIVES

We sought to compare left atrial (LA) volume to LA area and diameter for the prediction of adverse cardiovascular outcomes.

BACKGROUND

The incremental value of LA volume compared with LA area or diameter as a cardiovascular risk marker has not been evaluated prospectively for patients with sinus rhythm or atrial fibrillation (AF).

METHODS

Left atrial size was assessed with biplane LA volume, four-chamber LA area, and M-mode dimension for 423 patients (mean age 71 +/- 8 years, 56% men) who were prospectively followed for development of first AF, congestive heart failure, stroke, transient ischemic attack, myocardial infarction, coronary revascularization, and cardiovascular death.

RESULTS

Of the 317 subjects in sinus rhythm at baseline, 62 had 90 new events during a mean follow-up of 3.5 +/- 2.3 years. All three LA size parameters were independently predictive of combined outcomes (all p < 0.0001). The overall performance for the prediction of cardiovascular events was greatest for LA volume (area under the receiver operator characteristic curve: indexed LA volume 0.71; LA area 0.64; LA diameter 0.59). A graded association between the degree of LA enlargement and risk of cardiovascular events was only evident for indexed LA volume. For subjects with AF, there was no association between LA size and cardiovascular events.

CONCLUSIONS

Left atrial volume is a more robust marker of cardiovascular events than LA area or diameter in subjects with sinus rhythm. The predictive utility of LA size for cardiovascular events in AF was poor, irrespective of the method of LA size quantitation.

Prevalence of heart failure and systolic ventricular dysfunction in older Australians: the Canberra Heart Study

OBJECTIVE

To estimate the prevalence of heart failure (HF) and left ventricular (LV) systolic dysfunction in a population-based sample of older Australians.

DESIGN, SETTING AND PARTICIPANTS

A cross-sectional survey of 2000 randomly selected residents of Canberra, aged 60-86 years, conducted between February 2002 and June 2003. Participants were assessed by history, physical examination by a cardiologist, and echocardiography.

MAIN OUTCOME MEASURES

Age- and sex-specific prevalence rates of clinical HF and LV systolic dysfunction (defined as LV ejection fraction < or = 50%).

RESULTS

Of 1846 people eligible for our study, 1388 (75%) agreed to participate and 1275 completed all investigations (mean age, 69.4 years; 50% men). In the study sample, 72 subjects (5.6%; 95% CI, 4.4%-7.1%) had clinical HF that had been previously diagnosed and was confirmed by our assessment. A further 0.6% (95% CI, 0.3%-1.2%) had undiagnosed clinical HF (ie, evidence of structural heart disease and symptoms/signs of cardiac insufficiency without a previous diagnosis of clinical HF). Thus, the overall prevalence of clinical HF in the sample was 6.3% (95% CI, 5.0%-7.7%). Clinical HF increased in prevalence with advancing age (a 4.4-fold increase from the 60-64-years age group to the 80-86-years age group; P < 0.0001). Of the 75 subjects (5.9%; 95% CI, 4.7%-7.3%) with LV systolic dysfunction, 44 (59%) were in the preclinical stage of disease.

CONCLUSION

Diagnosed HF cases represent the "tip of the iceberg" for the national burden of HF and LV systolic dysfunction. Clinically identifiable HF cases can remain undiagnosed, and the majority of people with LV systolic dysfunction are in a preclinical stage of the disease.

Characteristics of left ventricular diastolic dysfunction in the community: an echocardiographic survey

OBJECTIVE

To determine the prevalence and predictors of left ventricular (LV) diastolic dysfunction in older adults.

DESIGN, SETTING AND PARTICIPANTS

A cross-sectional survey of 1275 randomly selected residents of Canberra, aged 60 to 86 years (mean age 69.4; 50% men), conducted between February 2002 and June 2003.

MAIN OUTCOME MEASURES

Prevalence of LV diastolic dysfunction as characterised by comprehensive Doppler echocardiography.

RESULTS

The prevalence of any diastolic dysfunction was 34.7% (95% CI 32.1% to 37.4%) and that of moderate to severe diastolic dysfunction was 7.3% (95% CI 5.9% to 8.9%). Of subjects with moderate to severe diastolic dysfunction, 77.4% had an LV ejection fraction (EF) > 50% and 76.3% were in a preclinical stage of disease. Predictors of diastolic dysfunction were higher age (p < 0.0001), reduced EF (p < 0.0001), obesity (p < 0.0001) and a history of hypertension (p < 0.0001), diabetes (p = 0.02) and myocardial infarction (p = 0.003). Moderate to severe diastolic dysfunction with normal EF, although predominantly preclinical, was independently associated with increased LV mass (p < 0.0001), left atrial volume (p < 0.0001), and circulating amino-terminal pro-B-type natriuretic peptide concentrations (p < 0.0001), and with decreased quality of life (p < 0.005).

CONCLUSION

Diastolic dysfunction is common in the community and often unaccompanied by overt congestive heart failure. Despite the lack of symptoms, advanced diastolic dysfunction with normal EF is associated with reduced quality of life and structural abnormalities that reflect increased cardiovascular risk.