Review of a Twiddlers Syndrome Patient with a Biventricular ICD

A 70-year-old female with Dilated Cardiomyopathy (DCM) with an ejection fraction less than 30% and left bundle branch block, attended to have a primary prevention Biventricular Internal Cardiac Defibrillator (ICD) fitted back in June 2015.

The procedure was uncomplicated; all parameters were within normal limits at the post implant check. Routine device check appointments 1 month and 5 month’s post implant were attended and all showed normal function with stable lead measurements. The patient had had a significant improvement in her heart failure symptoms with a reduction in shortness of breath and an increase in exercise capacity. The patient had been signed up to remote home monitoring at the first check, one-month post implant. In January 2016, an alert came through on the home monitoring system due to a high RV threshold. Interrogation of this data showed a drop in the RV signal amplitude.

The patient was contacted and the presence of symptoms was discussed over the phone. The patient over the previous few days had been feeling more short of breath, similar to pre having the device. It was arranged for the patient to attend the device clinic at the Barts Heart Centre the next day for further investigation. On attending the device clinic, the electrocardiograph (ECG) and interrogation of the Biventricular ICD highlighted significant amounts of under-sensing on the ventricular and atrial channels. This invalidated the percentage of Biventricular pacing and the histograms provided. Interrogation of the device showed there had been an abrupt drop in the lead impedance on the right ventricular (RV) lead from an average of 650 ohms to 380 ohms.  The RV lead was unable to capture at maximum output and sensing had gone down from 12mV to 0.7Mv. The atrial sensing amplitude had also diminished from 3.1mV to not sensing at all and the lead was unable to capture at full output. The LV threshold had risen significantly from 1.75V at 0.4ms to 3.75V@1.5mV. The device clinic registrar reviewed the patient and a chest X-ray was organised.

The chest X-Ray (performed in an anterior-posterior orientation) showed the atrial and right ventricular leads had pulled back significantly in to the superior vena cava (SVC) and the left ventricular lead had pulled back towards the proximal end of the coronary sinus (CS) compared to the position at original implant implant (Figure 1). The more striking finding was at the header of the device. The leads had a distinct twisted appearance not dissimilar to that seen in Twiddler’s Syndrome. All three leads had been displaced.

Figure 1: Anterior-Posterior X-Ray showing the position of the implanted cardiac device and leads January 2016 

In order to maintain patient safety, the Biventricular ICD was programmed VVI at 40 beats per minutes with LV pacing only at maximum output. Fortunately, the patient had received no inappropriate tachy therapy in the form of Anti-Tachycardia Pacing (ATP) or shocks. There was no capture of the phrenic nerve. Tachy therapy was disabled due to ill position of the RV lead and inability of appropriate sensing. The patient had an underlying rhythm of sinus rhythm with ventricular ectopy at around 60bpm.  On discussion of the findings with the patient, the patient denied any self-manipulation of the device. The device was noted to be mobile in the subcutaneous pocket in which it was implanted via the axillary subclavian vein. The patient was admitted to hospital with a view to extract the entire system under a general anaesthetic that same week.

On opening the pocket, the leads were almost twisted amongst each other in a spiral (figure 2). Once separated, the extraction procedure was routine with the leads being removed under simple traction. A new single coil active RV defibrillator lead was implanted into the low septum, a new RA lead was implanted in to the right atrial appendage and the CS was cannulated with a non-deflectable quadripolar electrophysiology catheter. A new quadripolar LV lead was implanted in to a lateral vein with no phrenic nerve stimulation. A new generator was attached and the device was secured in a pre-pectoral pocket to the muscle to try and prevent such a phenomenon occurring again.

Figure 2: Photo of leads and generator entwined prior to extraction

As previously noted, the patient had denied having manipulated the device herself. This was accepted by the Cardiologist.  When examining within the pocket, the operator had commented on the pocket being extremely loose but the device had been encapsulated. It was assumed that it was due to the device being loose in the pocket, the generator had moved with normal arm movements to cause the leads to twist together and pull back from their implanted position. The new generator and leads were attached were secured in a pre-pectoral pocket to the muscle to try and prevent such a phenomenon happening in future.

Twiddler’s syndrome is a rare phenomenon that usually occurs as a result of patients manipulating and turning the pacemaker within the implanted pocket. Mostly, patients deny doing this as often it is done subconsciously. Over time, manipulation of the device increases the size of the pocket and thus allows eventual rotation or flipping over of the device. This causes damage to the leads often by fracture and thus increases in lead impedance occur, often then resulting in loss of capture when pacing.  For such twisting of the leads to occur as in figure 2 without patient manipulation would be a very rare occurrence however has been seen in patients as soon as 2 days post implant. Often, this condition is seen within a year of implant. In order to try and prevent the phenomenon of Twiddles syndrome, various methods can be employed. For example, the size of the pocket should be kept to a minimum. The securing of the device to the pectoralis major helps prevent hypermobility of the can itself. Active fix leads generally are more secure and would help to avoid displacement.

The effects of Twiddler’s syndrome can be catastrophic, particularly in pacing patients with no underlying rhythm.  It is most often seen in patients with pacemakers, as generally they are smaller devices, but occasionally, as in this case, it is seen with bigger devices such as a Biventricular ICD’s. Predisposing factors to consider at implant would include obesity, patients with psychiatric illnesses, and more elderly patients. The steps mentioned above should be given careful consideration in such instances. 

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