Late percutaneous repositioning of a coronary sinus lead used for ventricular resynchronization.

Heart resynchronization therapy (HRT) is accepted in selected patients with heart failure. A persistent problem with the electrode implanted in the coronary sinus (CS) for left ventricular stimulation is that it can migrate either early or late. This involves possible loss or worsening of function and/or the possibility of phrenic stimulation, with consequent more or less frequent diaphragm contractions that are very unpleasant for the patient.1 Sometimes the problem can be resolved by means of device reprogramming, but not in others cases. Recently there has been a report of re-placement of this electrode pulling it with a steerable catheter introduced into the femoral vein, in 9 patients, with phrenic stimulation by early distal electrode displacement. Once it is repositioned, the authors place a stent in place compressing the electrode against the vein wall to achieve definitive stabilisation. Time from implant was 6 (6) months, with stability and good function after a follow-up of 7.7 (4.6) months. We present the case of a 65-year-old patient with severe left ventricular dysfunction, advanced left His bundle block, without coronary atherosclerosis, with a cardiogenic profile syncope, and implanted 43 months ago with an automatic HRT defibrillator. The implant was satisfactory in a posterolateral CS vein, with a stimulation threshold in the left ventricle of 2.1 V at 0.5 ms, with no phrenic stimulation at 10 V. Six months after implant placement the patient began to suffer occasional phrenic stimulation and on x-ray it was possible to see a slight distal displacement of the CS electrode, at that moment the problem was corrected by reprogramming. However, 10 months later phrenic stimulation reappeared. Initially the patient was in acceptable conditions, since the excellent stimulation threshold was at levels that did not cause said stimulation or this was only occasional or postural. After 3 years of implant placement the problem became continuous and disabling, and could not be fixed by reprogramming. It was decided to replace the generator (which is practically in ERI) and replace or change the electrode. The patient had an excellent cardiological condition since implant, and there was no doubt as to the need for the HRT. Before the replacement, and in agreement with the patient, percutaneous re-placement was attempted, following the experience mentioned above, in Heart pumping function requires synchronous mechanical activation. Electromechanical asynchrony can alter the heart contraction pattern. Left bundle block is an example of ventricular asynchrony related to functional mitral failure.1,2 Functional mitral failure in patients with left bundle block has multiple components. Including, asynchrony of the papillary muscles due to delay in ventricular conduction, that causes a delay in the contraction of the papillary muscles.3,4 The delayed movement of certain areas of the left ventricle (lateral wall or interventricular septum) leads to a reduction in the force of mitral valve closure due to the fall in systolic volume caused by the asynchronous mechanical contraction. During the last decade there has been a lot of interest in the relationship between functional mitral regurgitation and mechanical asynchrony, since by means of resynchronisation therapy it is possible to improve mitral regurgitation qualitatively and quantitatively in patients with both ischaemic and non-ischaemic cardiopathies.5 The case we present is of double interest: on one hand, proof of a relationship between ventricular asynchrony and functional mitral failure in a patient without systolic dysfunction or baseline alterations of their ventricular geometry, and, on the other, the usefulness of techniques that analyse myocardial deformation using ultrasound and make it possible to perform a detailed evaluation of the ventricular sequences of mechanical activation.