Idiopathic dilated cardiomyopathy and chronic atrial fibrillation.

BACKGROUND

Atrial fibrillation (AF) is common in idiopathic dilated cardiomyopathy (IDC). We explored the clinical characteristics of IDC patients with chronic AF compared with those with sinus rhythm (SR).

METHODS

A group of patients with IDC underwent extensive non-invasive and invasive evaluation during a hospitalization period. The patients were further divided into two groups with AF (n = 19) and SR (n = 68).

RESULTS

Left atrial diameter was greater (P<0·001), left ventricular end-diastolic diameter smaller (P<0·05), left ventricular end-diastolic and end-systolic volumes smaller (P<0·01 for all), mean pulmonary artery pressure and pulmonary capillary wedge pressure higher (P<0·05 for both), cardiac output and maximal oxygen consumption lower (P<0·01 and P<0·05, respectively), and the levels of N-terminal pro-brain natriuretic peptide and interleukin-6 higher (P<0·05 for both) in AF group compared with SR group. Left ventricular ejection fraction and left ventricular end-diastolic pressure were similar in both groups.

CONCLUSIONS

In spite of otherwise more unfavourable prognostic factor profile, left ventricular size was observed to be smaller in chronic AF compared with SR in well-characterized patients with IDC. The confirmation and possible explainers of this paradoxical phenomenon need further studies in larger patient cohorts.