Purpose: Tako-tsubo cardiomyopathy (TTC) is a transient form of acute heart failure. Besides ballooning of the left ventricle (LV), some patients develop wall motion abnormalities of the right ventricle (RV). This study assessed the prevalence, clinical significance and time course of RV involvement in patients with TTC by echocardiographic follow-up Methods: Over a 9-year period, we observed 76 TTC patients (69 f, 7m, age 70±12). By echocardiography, 15 pts (20%) had RV involvement. Clinical parameters, ECG, echocardiographic and angiographic findings were compared in patients with and without RV involvement. Results: RV wall motion abnormalities involved the apicolateral (n=9), mediolateral (n=4), anterolateral (n=1) and inferior (n=1) segments. Normalization of RV contraction always occurred before normalization of LV function (11±4 vs 33±27 days). In patients with RV involvement, time from symptom onset to hospital admission was shorter (4±5 vs 9±9 hours, p=0.004). The ECG on admission showed a higher heart rate (100±22 vs 86±22 beats per minute, p=0.03), and more patients with RV involvement developed giant negative T waves during follow-up (6/15 vs 10/61, p<0.05). Other ECG parameters were not different in patients with or without RV involvement. Cardiac markers, angiographic ballooning pattern of the LV and end-diastolic LV pressure were comparable in both groups. LV ejection fraction, however, was significantly lower in patients with RV involvement (42±12 vs 53±13%, p=0.005). Overall, more patients with RV involvement developed complications during the acute clinical course (73% vs 36%, p<0.01). There was a higher frequency of ventricular tachycardia (27% vs 5%, p<0.03), acute mitral regurgitation (20% vs 5%, p<0.04) and LV thrombus and/ or stroke (20% vs 5%) in patients with RV involvement, and time to complete normalisation of LV function was longer (32±27 vs 20±13 days, p<0.01). Conclusion: As assessed by echocardiography, RV involvement occurs in 20% of patients with TTC and is associated with a significantly higher rate of complications. Since ventricular tachycardia and thrombus or stroke are frequently observed, prolonged monitoring and anticoagulation is advisable in these patients.