A 47-year-old male developed heart failure due to dilated cardiomyopathy 12 years ago. A cardiac resynchronization therapy-defibrillator (CRT-D; Medtronic^® Viva XT CRT-D; AAI 60) was implanted due to VF 7 years ago, and as a bridge to transplantation, a HeartMate II® LVAD was implanted 4 years ago. No arrhythmia developed immediately after LVAD implantation; thus, his CRT-D shock therapy was turned off immediately after LVAD implantation. At the time of LVAD implantation, his transthoracic echocardiographic study showed a significant decrease in the left ventricular (LV) contractility (ejection fraction; 13%), dilation of left ventricle (51 mm in diastole) and trivial aortic regurgitation (AR) without opening of aortic valve but right ventricular (RV) contraction had maintained well relatively (RV fractional area change; 33%).

Eight months after LVAD implantation, the patient developed palpitations and was admitted to our hospital due to repeated VAs necessitating electrical defibrillation. Echocardiography showed the left ventricle diameter did not change, whereas right ventricle volume was slightly enlarged. The repeated VAs were also refractory to various anti-arrhythmic agents, including amiodarone, nifekalant, mexiletine and lidocain, with eventual progression to sustained VF. The hemodynamic compromise due to sustained VF resulted in liver congestion, which was alleviated with a phosphodiesterase type 5 inhibitor, diuretics, and rotation speed optimization (from 8800 to 9600 rpm). These interventions reduced organ dysfunction, suggesting that minimum-required perfusion to vital organs was maintained even under sustained VF. The patient was followed up on an outpatient basis thereafter.

Approximately 2 years after the development of sustained VF, paroxysmal AF was detected on the monitoring records of CRT-D, with a gradually increasing frequency. After 3 years of sustained VF, the patient was readmitted to our hospital due to worsening of symptoms associated with right heart failure and liver congestion (total bilirubin, 3.9 mg/dl). Although his electrocardiogram remained sustained VF (Fig. 1), the CRT-D revealed conversion of the sinus or atrial pacing rhythm to persistent AF. Transthoracic echocardiography revealed that fibrillation of the atrium resulted in the disappearance of not only the mitral flow but also the RV outflow tract doppler flow by the atrial kick (Fig. 2, Additional file 1, 2, 3, 4, 5 and 6). Under sustained VF, RV cardiac output is greatly dependent on atrial kick in which the contribution of atrial kick extraordinary enhanced. The hemodynamic study indicated that the pressure wave from the right atrium (RA) to the right ventricle was significantly flattened resulting that the pulmonary artery pulsatility index, which is defined as the ratio of pulmonary artery pulse pressure to right atrial pressure, was markedly decreased. It suggested a marked reduction in blood flow induced by RA contraction in persistent AF as opposed to sinus rhythm (Fig. 3). As the incremental rotation speed lead to an increase in RA pressure (RAP) from 19 mmHg to 22 mmHg, the rotation speed was set to 9600 rpm and the right heart congestion was treated with additional diuretics insufficiently and the enhanced level of total bilirubin was prolonged. Until four months later, heart failure was gradually improved and the level of total bilirubin decreased below 2 mg/dl. The monitoring records of CRT-D revealed the recovery of sinus rhythm during previous four months (Fig. 4). Although he had remained sustained VF, the recovery of sinus rhythm finely corresponded to the improvement of heart failure and the level of his total bilirubin decreased to 1.2 mg/dl. It intensely corroborated the contribution of persistent AF on the worsening of right heart failure.