Author + information
- Received June 30, 2015
- Revision received February 15, 2017
- Accepted February 24, 2017
- Published online November 20, 2017.
- José L. Morales, MD,
- Santiago Nava, MD∗ (, )
- Manlio F. Márquez, MD,
- Jorge González, MD,
- Jorge Gómez-Flores, MD,
- Luis Colín, MD,
- Marco A. Martínez-Ríos, MD and
- Pedro Iturralde, MD
- Department of Electrocardiology, National Institute of Cardiology “Ignacio Chavez,”, Mexico City, Mexico
- ↵∗Address for correspondence:
Dr. Santiago Nava, Instituto Nacional de Cardiología “Ignacio Chávez,” Department of Electrocardiology, Juan Badiano 1. Col. Sección XVI, Tlalpan 14080, México City, México.
Objectives This cumulative case study was performed to properly address the possible mechanisms, forms, and consequences of “twiddler’s,” “reel,” and “ratchet” syndromes.
Background Twiddler’s, reel, and ratchet syndromes are rare entities responsible for lead displacement of cardiac implantable electronic devices (CIED).
Methods From 2007 to 2012, 1,472 CIED were implanted at our center. Eighty-nine cases were reviewed for failure of pacing circuit integrity. Only 9 met the inclusion criteria for idiopathic lead migration (ILM) and were grouped as ILM (twiddler) or ILM (reel). For a pooled analysis of cases, a review of the literature from 1990 to 2012 was performed, and the authors identified 78 cases from 64 publications.
Results The study population consisted of 87 cases (45 women; median age, 66 years; 46 with ILM [twiddler] and 41 with ILM [reel]). Migration affected only 1 lead in 65% of 46 devices with more than 1 lead. None of the previously reported risk factors—manual manipulation of the device, elderly age, obesity, oversized pocket, and psychiatric history—correlated with the risk of ILM.
Conclusions Neither manual manipulation of the device nor the other traditional risk factors reported in the literature for ILM syndrome correlated with the risk of ILM.
Lead migration is an extremely rare complication of cardiac implantable electronic devices (CIED). It was previously referred to by many names including “twiddler,” “reverse twiddler,” “reel,” “reverse reel,” and “ratchet” syndromes (Figure 1). Previous attempts have been made to encompass all terms with a proper definition, classification, and pathophysiology (1,2). All of these labels are based on the mechanism of a possible rotation of the pulse generator (PG). For the 2 main variants, “twiddler” and “reel,” the proposed risk factors include the creation of a large pocket for the generator, lack or loose PG fixation, redundant subcutaneous tissue or skin, and compulsive PG manipulation behavior (3). Although this can be true in some cases, a thorough review of the literature cannot solidly prove these events. An active role of the PG and a passive role of the electrode have generally been implicated in the mechanism (1,3).
Considering that all these rare entities share 2 common features—the absence of an obvious cause and the abnormal displacement of the leads—we coined the name idiopathic lead migration syndrome (ILMS) to describe an unknown cause of leads migrating from their original position (in the heart or pocket), with or without dislodgement or torsion. Because ILMS has relevant implications for patients’ safety, we performed a case study and review of the literature to address possible mechanisms, examine the different forms involved, and establish proper definitions and consequences of ILMS.
ILMS is defined as displacement of the lead out of the cavity in which it was originally implanted by shortening of the cable length and increasing redundancy around the generator pocket. Cases were grouped as ILM-twiddler variant (ILM-t) if x-ray imaging showed that the lead was tangled in its longitudinal axis and retracted toward the PG (Figure 1A) or as ILM-reel variant (ILM-r) if the lead was reeled around the generator without torsion (Figures 1B and 1C). Clinical and radiological differential definitions used in patients with other causes of lead malfunction are shown in Table 1.
We searched cases treated in our institution that required revision of the pacing circuit integrity for lead malfunction between 2007 and 2012, and selected those that met ILMS criteria. To enable a pooled analysis of cases, a review of the literature from 1990 to 2012 was performed in the SciELO, PubMed/MEDLINE, Embase, Ovid, and Google Scholar databases. The search criteria consisted of a combination of the words twiddler, reel, ratchet, lead dislodgment, lead retraction, and pacemaker. Cases were selected if they described a brief clinical history; referred to pocket manipulation, lead characteristics, PG type, time to diagnosis, symptoms; and showed radiological evidence of dislodgment and/or a picture of the lead (to enable us to properly identify whether it was an ILM-t or an ILM-r). If the data were insufficient, we sent an e-mail questionnaire to the corresponding author, asking for the missing data (Online Figure 1). Epicardial leads were excluded. The time to diagnosis was considered the moment at which the alteration was confirmed by x-ray imaging.
Numerical variables are expressed as mean and SD or median and range for normally distributed variables. Categorical variables are expressed as percentages. Comparisons between ILM-t and ILM-r were performed using the Student's t-test or Mann-Whitney U test. Categorical variables were analyzed using chi-square or Fisher exact test when necessary. Values of p ≤ 0.05 were considered statistically significant. Agreement among radiological analyses for each event was measured by using the Kappa coefficient test.
From our institution, 89 of 1,472 CIED implanted from 2007 to 2012 were initially considered with an indication for review of the pacing circuit integrity for lead malfunction. Only 9 met the ILM criteria as defined for the present study. From 136 references obtained in the literature review, only 64 were eligible, for a subtotal of 78 cases that met ILM criteria. To obtain more details on the cases reported of the literature, 41 e-mails were sent, but only 16 were answered, so the information available for analysis was complete in 89.5% of cases (Table 2). Compared with other variables, information about the PG and leads was scarce in the analyzed publications (Table 2).
The total study population for final analysis included 87 cases (45 females; median patient age, 66 years [range 5 to 91 years]) (Table 2). From the 87 cases analyzed, 46 were classified as ILM-t and 41 as ILM-r (Kappa 0.73). Figure 2 shows the distribution of events (ILM-t, ILM-r) according to: 1) CIED type; and 2) pacing site (single or double chamber). Of the 146 leads involved in all CIED, 103 presented migrations (Figure 2).
Analysis of the 46 devices with more than 1 lead revealed that migration affected only 1 lead in 30 (65%) cases. There was no difference in the incidence of atrial versus right ventricular migration, 29 (28%) versus 26 (25%), respectively (p = 0.59). In cardiac resynchronization therapy devices (CRT-D), there was a tendency toward more frequent migration of the coronary sinus electrode (9 of 13 devices; p = 0.05).
An analysis of the classical risk factors reported in the literature for twiddler's syndrome is shown in Table 2. The risk factor considered most important in the literature, manual manipulation of the device, was acknowledged in 14 cases (16%). None of the other traditional risk factors (old age, obesity, oversized pocket, and history of psychiatric disorder) were associated with the development of ILM. Two variables were significantly predominant in ILM: a left pectoral implant (73%) and silicone-insulated electrodes (67%).
The median time for diagnosis was 90 days (range 1 day to 7 years) (Table 2). The time to diagnosis differed among the groups: 40 days (range 1 to 1,460 days) for ILM-r versus 272.5 days (range 7 to 2,555 days) for ILM-t (p = 0.001). ILM events were symptomatic in 45 patients (52%), including extracardiac stimulation (n = 13), syncope (n = 8), worsening of heart failure (n = 4), inappropriate shocks by the ICD (n = 10), and ventricular fibrillation episodes that were not detected (n = 4). Other symptoms such as feeling device movement were reported by 6 patients. There was a higher tendency for ILM-t in higher-volume devices (ICD and CRT-D, 39 ± 29.9 vs. 25.5 ± 14.5; p = 0.035) and wider-diameter electrodes (p = 0.002).
Bayliss et al. (4) coined the term twiddler’s syndrome to refer to the unexplained phenomenon of electrode torsion. Other reports described a variant in which the electrode is retracted along the generator as in a fishing reel so it was described as “reel” (5). Von Bergen et al. (6) described a case of a dual-chamber pacemaker with a “reel” appearance on the radiograph in 1 lead only. They proposed that the pathogenic explanation was a progressive movement of the lead produced by arm movement in which inadequate fixation of the lead fixation sheath allowed movement toward the generator but not in the opposite direction, acting as a unidirectional brake and, therefore, called the phenomenon “ratchet.” In our analysis, 65% of the cases of ILMS-r could be considered “ratchet.” Because we believe that the same mechanisms underlined both reel and ratchet, we therefore analyzed them as 1 entity.
Previously described risk factors for both twiddler’s and reel syndromes include: external manipulation, oversized pocket, redundant skin, advanced age, female sex, young age, obesity, and obsessive-compulsive behavior (translating into external manipulation). Bayliss (4) suggested that, in twiddler’s syndrome, force is applied externally to the PG, provoking torsion, rotation, and retraction of the lead until the complete dislodgment from the endocardium. Because the majority of patients denied manipulating the device, it has been assumed that patient is unaware of the manipulation. Some authors have proposed that it is possible that the lead itself is an active element in the process (7,8).
The aforementioned hypotheses have several weaknesses because they do not explain: 1) how it is possible to have only 1 lead involved in CIED when more than 1 lead is present; 2) reports of these phenomena in animals (9,10); 3) it develops despite submuscular pockets and is difficult to manipulate (11); and 4) even in cases of frank manipulation of the device such as suicide attempts, the syndrome does not occur (12,13). In the present analysis, the manipulation of the generator, the principal element in the theory of the twiddler syndrome, was documented in only 16% of patients, whereas none of the other risk factors were significant.
Multiple variables may play a role in the mechanism of lead displacement, such as suture type (absorbable vs. not absorbable), suture sleeve tension, and CIED fixation. However, lead retraction is possible considering the interaction of 3 elements: 1) a source of energy produced with every muscular movement of the shoulder; 2) the transmission of that energy to the lead through interaction between the muscle and the outer insulation generating the movement in 1 direction; and 3) something that holds back the lead and prevents recoil (Figure 3).
During percutaneous device implantation, at least 2 muscles are crossed: the pectoralis major, which participates in abduction, adduction, rotation, and flexion; and the subclavius, which provides stability to the shoulder joint (14). These muscles could provide energy that pulls and twiddles the lead. The degree of this interaction will depend on the coefficient of friction of the outer lead insulation and the contact with the muscle fibers (15). It is known that the distribution of the muscular strength in an arch of movement is not uniform; rather, it is distributed into 2 vectors using the bone segment of insertion as a reference in which one runs perpendicularly and is directly responsible for the movement and the other runs parallel and provides stability (16). Mechanically, the action of the pectoralis major and subclavius muscles could behave in a similar manner, trapping the lead and subjecting it to these vectors, producing a torque-like movement (Figure 3). However, these muscle–lead interactions alone do not explain the disorder because these forces will dissipate once they stop influencing the lead, rendering a mechanism that will hold these forces necessary. The suture sleeve may act as a unidirectional brake (as in a ratchet), preventing dissipation of force and storing it, causing the lead to tangle proximally (typical or common twiddler), distally (reverse twiddler) (17–20) (Figures 1D and 1E), or both (Figure 4).
It is important to note that the source of energy is always present, whereas the other 2 components have a random presentation, and each lead is an independent element. This independent participation of each lead could be supported by cases of ratchet reported in the literature in which only 1 lead is affected.
Although it is possible that the timing of the event can be influenced by symptoms associated with device dysfunction, the absence of symptoms can delay its recognition. An interesting observation was that ILM-r had an earlier presentation post-implantation (40 days [range 1 to 1,460 days]) than ILM-t (272.5 [range 7 to 2,555 days]; p = 0.001) and almost one-half of the cases presented symptoms related to lead dysfunction. In current devices, the stored electrogram data and long-distance monitoring could elucidate the exact moment of lead detachment (21,22).
There is no clear explanation why ILM presents in different forms and can present in some patients as ILM-t or ILM-r. However, it is possible that the fibrotic capsule may play a role. In ILM-r, the lead may find its way around the generator in a more compliant and immature fibrotic capsule, which allows it to accommodate the generator. In ILM-t, a less compliant fibrotic capsule may generate resistance to lead passage to the pocket because it is sealed, causing that energy accumulated to twist the lead around its longitudinal axis, coil on itself, and push it through the tissues in a disorderly manner (7,23) (Figure 3). Another observation is that ILM-t was more frequent in patients with ICD/CRT-D (Table 2), in which cases, the shape and larger volume of the device might influence capsule formation or lead twisting (7).
There are no clear risk factors associated with the development of ILMS, although some cases have been associated with repetitive arm movements (24–27). The technique by which the device is implanted does not seem to be a relevant factor either because it has been reported in cases of epicardial (28), abdominal (29), and retropectoral implants (30) by venous puncture or cutdown (31); it can appear after the replacement of a generator or be recurrent (32,33). Preventive measures have included adequate fixation of the PG to the muscular fascia, tight lead fixation, and the use of a Dacron patch over the PG (34).
More than one-half of the patients in the present study experienced symptoms, primarily extracardiac stimulation; in one-third of cases, this was considered life-threatening. An uncommon symptom was the perception of movement inside the pocket (34,35), and the device may appear rotated on chest radiographs (32,33). The force accumulated by the lead might move the device. In fact, in some cases, enough force accumulated to break and fragment the lead (36–40).
In our institution, we identified 9 events of 1,472 implants (0.61% in 5 years), similar to other series (23). Of all causes of failure at the electrode–tissue interface, early dislodgement of the lead after implantation related to improper fixation to the tissue was the main cause, followed by ILMS (81% and 10.1%, respectively). This finding suggests that this complication might be underestimated (Figure 5).
The descriptive nature of this study and the absence of a control group prevented us from obtaining definitive risk factors or a pathogenic mechanism. The higher rate of ILM presentation in the left pectoral region and with silicon-insulated leads in our study can simply reflect the predilection of the implant site by the physician, and a higher frequency of this type of lead.
ILM syndrome refers to a change in lead position after implantation with or without dislodgment or torsion. Its causative mechanism is uncertain: device manipulation (deliberate or while unconscious) may be responsible for some instances, although it is possible that mechanical forces inherent in muscle movement may contribute. None of the main risk factors reported in the literature correlated with the risk of ILM.
CLINICAL COMPETENCIES: Since the first reports of twiddler’s syndrome and its variants, its etiology has been attributed to the manipulation of the pulse generator by the patient, despite its rare occurrence and evidence consisting of only isolated reports. To prove this hypothesis, the authors evaluated this phenomenon using a cumulative case analysis that allowed them to establish a more plausible hypothesis.
TRANSLATIONAL OUTLOOK: With this operational definition, idiopathic lead migration is the second-most common cause of lead detachment.
The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
All authors attest they are in compliance with human studies committees and animal welfare regulations of the authors’ institutions and Food and Drug Administration guidelines, including patient consent where appropriate. For more information, visit the JACC: Clinical Electrophysiology author instructions page.
- Abbreviations and Acronyms
- cardiac implantable electronic device
- cardiac resynchronization therapy devices
- implantable cardioverter defibrillator
- idiopathic lead migration
- idiopathic lead migration (reel)
- idiopathic lead migration syndrome
- idiopathic lead migration (twiddler)
- pulse generator
- Received June 30, 2015.
- Revision received February 15, 2017.
- Accepted February 24, 2017.
- 2017 American College of Cardiology Foundation
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