Author + information
- Aeshita Dwivedi, MD,
- Jacqueline Joza, MD,
- Kabir Malkani, BA,
- Todd B. Mendelson, MD,
- Silvia G. Priori, MD, PhD,
- Larry A. Chinitz, MD,
- Steven J. Fowler, MD and
- Marina Cerrone, MD∗ ()
- ↵∗Cardiovascular Genetics Program, Leon H. Charney Division of Cardiology, Department of Medicine, New York University Langone Medical Center, 435 East 30th Street, 723H-3, New York, New York 10016
The differential diagnosis between benign syncope common in a young population and life-threatening arrhythmic ones represents a major challenge in the management of patients with inherited arrhythmias (IAs) (1). In this population, ventricular arrhythmias can often be hemodynamically tolerated, adding to the complexity of the event’s adjudication (1). The probability of documenting the rhythm underlying a fainting event or a silent arrhythmia with periodic external recordings is low and inadequate to the need of long-term, real-life longitudinal monitoring. Implantable loop recorders (ILRs) have a recognized value for the evaluation of syncope and palpitations (2), but data on their role for IA are scarce. Furthermore, the advent of injectable devices increased their tolerability and acceptance, making them suitable also for children.
Here, we provide retrospective data on the largest group of IA patients implanted with ILRs from a single tertiary center. Data are descriptive and expressed as percentage, median, and interquartile range (IQR).
Between 2009 and 2017, 52 patients from the NYU Langone’s Cardiovascular Genetics Program were offered an ILR, and 45 (20 men) underwent implantation. Thirty-five (77%) patients received an injectable ILR. The median age at implant was 29.15 (IQR: 16.33 to 41.78, range 3.70 to 75.70) years and median follow-up (FU) was 26.93 (IQR: 17.33 to 39.41) months. No complications were observed. The frequency of ILR interrogation was once a month or sooner in case of patient-activated event or reported symptom. After 2014, all patients were on remote monitoring (Carelink, Medtronic, Inc., Minneapolis, Minnesota), with possibility for daily alerts if needed. Conditions included in the study were long QT syndrome (n = 15, 33%), Brugada syndrome (n = 11, 24%), catecholaminergic polymorphic ventricular tachycardia (n = 5, 11%), arrhythmogenic cardiomyopathy (n = 3, 7%), hypertrophic cardiomyopathy (n = 3, 7%), short QT syndrome (n = 1, 2%), dilated cardiomyopathy (n = 2, 4%), and unexplained syncope with family history of juvenile sudden death and suspect IA (n = 5, 11%). Genetic testing was positive in 23 (51%) individuals.
Syncope or presyncope of unclear origin and complex adjudication was the indication to implant in 27 (60%) patients; 13 (29%) described frequent palpitations, while long-term monitoring for high-risk features in the absence of symptoms was the indication in 5 (11%). All patients underwent comprehensive clinical work-up based on diagnosis, including noninvasive monitoring, that did not result in symptom correlation at time of recording.
The majority of patients (n = 32, 71%) experienced symptoms or had a silent arrhythmia recorded, with a median time of 5.5 (IQR: 3.0 to 11.0) months post-implant. Overall, 21 of 33 symptomatic patients (63.6%) reproduced the initial symptom that led to the ILR implant, with median FU to repeat syncope of 5.5 (IQR: 4.0 to 12.5) months and 6 (IQR: 3.0 to 12.5) months for palpitations. Figure 1 summarizes the pre- and post-ILR history and the type of arrhythmias documented. Importantly, no syncope or presyncope was associated with any life-threatening rhythms, thereby avoiding an indication for implantable cardioverter-defibrillator (ICD) implantation based on recurrent unclear syncope and IA diagnosis. Of note, no syncope incurred lack of memory of the device, and we were able to adjudicate all events. Supraventricular arrhythmias were recorded in 10 patients (Figure 1), with 5 undergoing successful radiofrequency ablation and remaining symptom-free after 42 (range 8 to 43) months.
Sixteen (35.5%) patients underwent ILR explant after 31 (IQR: 13 to 41) months, for end of battery life (n = 10); pacemaker (n = 1) or ICD implant (n = 3), in which 2 were placed on patients’ request, without evidence of malignant arrhythmias; and successful premature ventricular contraction ablation (n = 1). Five patients (11%) requested a reimplant after reaching end of battery life, reassured by the possibility of longitudinal monitoring and high tolerability of the device.
In our study, most IA patients had a recurrence during the time of ILR monitoring, confirming that this is an effective tool granting sufficient FU to adjudicate events (2). Although a repeated syncope in the setting of IA often prompts an ICD recommendation, the lack of malignant arrhythmias detected in our data underlines the importance of accurate longitudinal monitoring and careful event adjudication in these patients, whose age and features make them prone to vasovagal syncope and supraventricular arrhythmias. The ILR demonstrated to be a significantly more effective and more tolerable tool than noninvasive testing (2), whose probability of coinciding with clinical symptoms or silent arrhythmias is particularly low in this category of patients, whose events tend to be rare and separated in time, and still need prompt assessment.
The ILR had also a positive psychological impact in our population, that felt reassured by the longitudinal remote monitoring and evidence of the benign substrate underlying most symptoms. In conclusion, injectable ILRs are a well-tolerated and effective tool to adjudicate events and ensure long-term monitoring of arrhythmic risk in patients diagnosed with IA.
Please note: The authors have reported that they have no relationships relevant to the contents of this paper to disclose. Drs. Cerrone and Fowler contributed equally to this work, and are joint senior authors. Drs. Dwivedi and Joza contributed equally to this work, and are joint first authors.
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.
- 2018 American College of Cardiology Foundation