Recurrent Syncopal Events Research Articles

Inappropriate Defibrillator Shock Due to Oversensing. What to Do?

In spite of advanced designs of implantable cardioverter defibrillators (ICD) lead fracture remains the most frequent complications. ICD interrogation is mandatory for the diagnosis of all type of lead failures. We report the case of an 18 years old boy, diagnosed with Jarvell and Lange Nielsen syndrome since he was 2 years. He received first Nadolol then he got ICD and a prophylactic left sympathectomy after he had a cardiac arrest. One year later, the ICD started delivering shocks, appropriate at first then inappropriate due to oversensing. Long QT syndrome is a rare congenital disorder characterized by repetitive episode of syncope and cardiac arrest due to polymorphic ventricular tachycardia. The treatment is mostly pharmaceutical with B-blockers. The indication for an ICD is in class I for patients who survived cardiac arrest, and for patients who experience recurrent syncopal events under B-blockers. On the other hand, in case of contraindicated or not tolerated medical therapy, ICD is recommended as a class IIa, according the ESC guidelines of 2022. An ICD must be interrogated frequently and have its measurements reviewed in order to detect lead dysfunction. The detection of high impedance suggests conductor fracture along with inappropriate defibrillator shocks delivered by the ICD. Oversensing with normal pacing impedance is the initial electrical abnormality with either conductor fracture.(4) The fractured lead will either be left inside the patient or removed, depending on specific factors related to the patient and the ICD. (5)

Implementation of supervised physical training to reduce vasovagal syncope recurrence: A randomized controlled trial.

Physical techniques used for the prevention of vasovagal syncope have limited evidence for efficacy. We aimed to evaluate multimodal supervised physical training as a treatment approach. In this 1:1 randomized trial, patients with ≥2 episodes of clinically diagnosed vasovagal syncope were included. On top of standard care, the intervention arm performed supervised tilt training and aerobic exercise in six sessions at a cardiac rehabilitation center (three sessions during the first month, and then at 3-month intervals), plus home tilt training. The control arm received standard care with a similar protocol of home tilt training. The primary outcome was time to first syncopal recurrence during 1year of follow-up. Fifty participants were randomized (mean age: 34.5 ± 14.8 years; 64% female). The rate of syncopal recurrence was 28% and 64% within the intervention and control arms, respectively, with significantly higher syncope-free survival at 1year in the intervention arm (Log-rank p = .003). The frequency of recurrent syncopal events was significantly lower with physical training (p = .017). Participants in the intervention arm reported significantly higher adherence to the home tilt training program (80% vs. 52%; p = .037). Among patients with recurrent vasovagal syncope, a supervised program of tilt training and aerobic exercise reduced syncopal recurrence. Future trials are warranted to further investigate multimodal supervised physical techniques as a therapeutic approach in treating vasovagal syncope.

Idiopathic Intractable Diarrhoea Leading to Torsade de Pointes.

An 81-year-old lady was admitted to our hospital with a 3-year history of noninfective diarrhoea and recurrent syncopal events over the last 3 months. Her initial electrocardiogram (ECG) revealed trigeminy and prolonged QTc interval. She had a structurally normal heart with no coronary artery disease. Investigations revealed low potassium at 3.0 mmol/L. Sigmoidoscopy and colonoscopy suggested a possible diagnosis of diverticulitis. Soon after admission she had an unresponsive episode with spontaneous recovery. Telemetry and Holter analysis confirmed multiple episodes of polymorphic ventricular tachycardia (Torsade de Pointes). Following electrolyte supplementation the episodes of polymorphic VT improved. Due to the protracted nature of the diarrhoea, the recurrent syncopal events, and recurrent hypokalaemia documented over recent years, an Implantable Cardioverter Defibrillator (ICD) was sanctioned by the multidisciplinary team (MDT). In summary, chronic diarrhoea may result in life threatening polymorphic VT due to hypokalaemia and QTc prolongation. In these patients an ICD may be considered.

Use of implantable loop recorders in patients with Brugada syndrome and suspected risk of ventricular arrhythmia

Implantable cardioverter defibrillator (ICD) therapy is recommended in patients with Brugada syndrome (BS) who experienced aborted sudden cardiac death (SCD) or syncope while the risk stratification of ventricular arrhythmias is a difficult step in patients with atypical symptoms. Implantable loop recorder (ILR) use has been proposed to study patients with unexplained recurrent syncopal events, but its usefulness remains to be defined in patients with BS. In this retrospective study we aimed to investigate the effectiveness of ILR as a diagnostic tool in BS patients suspected of low or moderate risk of SCD. We gathered data from 11 ILR recipients with supposed risk of ventricular arrhythmia, issue of Amiens registry of 204 patients with BS. We reported clinical events before and after implant, electrocardiogram (ECG) characteristics, ILR findings, and its limitations as well as tried to specify ILR utility in diagnosis approach and its consequent contribution to guide the optimal therapy. Within the 11 patients (8 men, 3 women), 9 were symptomatic, and 5 had a spontaneous Type 1 ECG pattern. During mean follow-up period of 33 months, 8 patients had a recurrence of symptoms with a mean delay of 9 months after implant. Bradycardia (two atrioventricular blocks and two sinus bradycardia) was detected in four out of eight patients (50%), and there was no ventricular arrhythmia in any patient during symptomatic events which included six vasovagal syncopes and two epileptic seizures. Two initially asymptomatic patients did not experience any symptoms after ILR implant and their ILR recordings did not reveal any arrhythmias. The ILR contributed to the exclusion of a ventricular arrhythmia as a mechanism of an atypical syncope in patients with electrocardiographic BS and the suspension of the ICD implant. Episodes of transient symptomatic bradycardia were the most common findings suggesting the vagal mechanism of symptoms. The use of ILR should be considered in selected patients with atypical syncope and spontaneous or transient Type 1 ECG pattern.

A randomised prospective comparison of three protocols for head-up tilt testing and carotid sinus massage

Introduction Head-up tilt testing is an important tool in the diagnosis of syncope. Several different protocols are in use. This study aimed to compare three different protocols in an unselected population of patients with recurrent unexplained syncope and to assess long-term outcome using conventional tilt-directed management or implantable loop recorder (Reveal Plus)-directed management, allowing evaluation of the sensitivity and specificity of the technique. Methods Patients with recurrent unexplained syncope were randomized to one of three tilt protocols: Drug-free 70° tilt, 45 min, CSM at 5 and 45 min. GTN 70° tilt, 35 min, CSM at 5 min, 400 μg of glyceryl trinitrate spray administered sublingually at 20 min. Adenosine 70° tilt, 5 min, CSM when blood pressure is stable in upright position, adenosine bonus at 150 μg/kg after CSM. Tilts were terminated at the onset of syncope, when systolic BP reached 60 mm Hg, or in the presence of prolonged hypotension (> 3 min systolic BP < 80 mm Hg). Appropriate therapies were commenced according to the result of the tilt test. All patients without a definite indication for immediate cardiac pacing (asystolic tilt) were randomized to conventional management or ILR implantation. Recurrent syncopal events were compared to tilt outcome, allowing estimation of sensitivity and specificity. Results Of 214 patients, aged 68 ± 18 years, 55% were female, with a median of three previous syncopes. 13 patients received pacemakers due to asystolic syncope during tilt testing. The proportion of VASIS classification diagnoses was similar with each protocol; however more positive diagnoses resulted from the GTN protocol ( p = 0.0013). 47% of patients achieved a diagnosis with tilt testing. We were able to correlate a subsequent spontaneous syncope to tilt result in 36 patients (18%). Heart rate during a spontaneous event was similar to that obtained during tilt testing (± 10%) in 55% of cases. Sensitivities for combined protocols, adenosine, GTN, and drug-free protocols were 50%, 50%, 100%, and 21%, respectively. Specificities were 85%, 100%, 75%, and 71%, respectively. Conclusions A high diagnosis rate for unexplained syncope can be achieved with tilt testing. The GTN protocol resulted in significantly more diagnoses than the other compared protocols with good sensitivity and adequate specificity. Sensitivity of the drug-free tilt test was lower than drug-augmented tilt testing.

Pharmacological treatment of reflex syncope.

Patient education, identification of possible triggers of syncope and reassurance are a central feature of the management of patients with reflex syncope. Patients should be advised as to the importance of adequate hydration and taught physical countermaneuvers to enhance cardiac venous return. These maneuvers are sufficient for most patients, however, for a small number of patients who continue to have recurrent syncopal events, pharmacological intervention may be considered. Volume expansion can be enhanced with salt and fludrocortisone. Agents from diverse pharmacological classes have been used to attenuate the reflex response, enhance vasoconstriction and attenuate vagal outflow. Alpha adrenoreceptor agonists, anticholinergic agents, theophylline, beta adrenoreceptor antagonists, serotonin reuptake inhibitors and disopyramide are the most widely studied. None of these agents has shown a consistent therapeutic benefit in clinical trials.

Effectiveness of sotalol treatment in symptomatic Brugada syndrome

We describe a 53-year-old man with recurrent syncopal events and a malignant family history who was treated for 13 years with sotalol drug therapy with no further occurrence of Brugada syndrome symptoms. Genetic testing revealed that he carried a Brugada syndrome sodium channel SCN5A mutation (4189delT). This finding suggests that sotalol may be of therapeutic benefit in such patients.

Diagnostic yield of external electrocardiographic loop recorders in patients with recurrent syncope and negative tilt table test.

External electrocardiographic loop recording permits extended cardiac rhythm monitoring and ECG storage before and after device activation. The purpose of the study was to assess the diagnostic yield of external loop recorders in patients with more than two syncopal events within the last 6 months and a negative tilt table test. Twenty-four consecutive patients (51 +/- 14 years, male n = 9) were enrolled with 3 +/- 4 recurrent syncopal events within the last 6 months and no overt structural heart disease. The loop recorder CardioCall continuously records a two-channel ECG via skin electrodes. When activated, up to 4.5 minutes of the ECG preceding activation is stored. The time between tilt table testing and monitoring was 5 +/- 4 weeks. The average monitoring period covered 50 +/- 22 days. Recording was either unsuccessful or terminated prematurely in 5 patients. The reasons were skin irritation secondary to the electrodes in two patients, cable damage in one patient, and two patients inadvertently erased the stored data when replacing the batteries. Fourteen patients activated the loop recorder at least once. Symptoms leading to device activation were syncope (n = 1), dizziness (n = 11), feeling unwell (n = 7), palpitations (n = 5), headaches (n = 1), and chest pain (n = 1). The loop recorder documented sinus tachycardia during the syncopal event. Sinus tachycardia was also observed in 7 other patients, and atrial flutter in two patients. Eight patients had recurrent syncope with two patients experiencing syncope prior to the monitoring period, one syncope occurred in a patient who inadvertently erased the stored data, one event coincided with sinus tachycardia, and 4 (17%) patients had syncope during 15 +/- 10 months after termination of loop monitoring. The external loop recorder was not very useful for arrhythmia detection in patients with syncopal events, no overt heart disease, and a negative tilt table test because the cardiac rhythm was stored in only 1 of 8 (13%) patients with recurrent syncope. Reasons for the low diagnostic yield of external loop recorders were infrequent syncopal events after the baseline evaluation, with rare events during the limited monitoring period in particular, and premature termination or unsuccessful recording in 21% of patients.

Psychiatric conditions in patients with recurrent unexplained syncope.

The relationship between syncope and psychiatric disorders is little investigated. This study evaluated the prevalence of psychiatric diseases and prognostic outcome in patients with recurrent unexplained syncope. After an inconclusive standard diagnostic work-up for syncope, including head-up tilt testing, a psychiatric evaluation was offered to 50 consecutive patients with recurrent syncope. The evaluation was accepted by 26 patients (77% females, 36 +/- 16 years) and refused by 24 (63% females, 50 +/- 19 years). A psychiatric disorder was diagnosed in 21 (81%) patients: 12 had depression, four panic attacks, two general anxiety, and three a somatization disorder. Only five patients showed normal psychosocial function. Of the patients with psychiatric disorders four accepted psychiatric care, such as psychotherapy and/or pharmacotherapy; 17 patients refused treatment. During 6 months of follow-up no patient under psychiatric care had syncope, while all patients without psycho- or pharmacotherapy had recurrent syncopal events. In these patients the median of syncopal episodes was three in a 6 months interval before and after clinical assessment. Patients who refused both psychiatric evaluation and therapy continued to experience syncope as before. In patients with recurrent unexplained syncope psychiatric alteration is common. However, patients seldom accepted a psychiatric evaluation and treatment.

Mutation of the gene for IsK associated with both Jervell and Lange-Nielsen and Romano-Ward forms of Long-QT syndrome.

Long-QT syndrome (LQTS) is a disorder of ventricular repolarization characterized by a prolonged QT interval, syncope, seizures, and sudden death. Recently, three forms of LQTS have been shown to result from mutations in potassium or sodium ion channel genes: KVLQT1 for LQT1, HERG for LQT2, and SCN5A for LQT3. IsK, an apparent potassium channel subunit encoded by KCNE1 on chromosome 21, regulates both KVLQT1 and HERG. This relationship makes KCNE1 a likely candidate gene, because mutations of these genes are known to cause both the autosomal dominant Romano-Ward and recessive Jervell and Lange-Nielsen (JLN) forms of LQTS. We screened 84 unrelated patients with Romano-Ward and 4 with JLN for possible mutations in KCNE1. We identified one homozygous mutation in a JLN patient that results in the nonconservative substitution of Asn for Asp at amino acid 76. The patient is congenitally deaf-mute, with recurrent syncopal events and a greatly prolonged QTc interval. The proband's mother and half-sister are both heterozygous for this mutation. Remarkably, both these family members have prolonged QTc intervals and would have been classified as Romano-Ward patients if not for the proband's diagnosis of JLN. This mutation was not identified in more than 100 control individuals. These data provide strong evidence that KCNE1 mutations represent a fifth LQTS locus (LQT5). Further functional analysis, as well as the identification of more LQTS patients with KCNE1 mutations, will be important to confirm the role of IsK in LQTS.

A doppler index for evaluating the effect of vasodilator therapy on aortic wave reflections

Head-up tilt testing is an important tool in the diagnosis of syncope. Several different protocols are in use. This study aimed to compare three different protocols in an unselected population of patients with recurrent unexplained syncope and to assess long-term outcome using conventional tilt-directed management or implantable loop recorder (Reveal Plus)-directed management, allowing evaluation of the sensitivity and specificity of the technique.Patients with recurrent unexplained syncope were randomized to one of three tilt protocols:Tilts were terminated at the onset of syncope, when systolic BP reached 60 mm Hg, or in the presence of prolonged hypotension (> 3 min systolic BP < 80 mm Hg). Appropriate therapies were commenced according to the result of the tilt test. All patients without a definite indication for immediate cardiac pacing (asystolic tilt) were randomized to conventional management or ILR implantation. Recurrent syncopal events were compared to tilt outcome, allowing estimation of sensitivity and specificity.Of 214 patients, aged 68 ± 18 years, 55% were female, with a median of three previous syncopes. 13 patients received pacemakers due to asystolic syncope during tilt testing. The proportion of VASIS classification diagnoses was similar with each protocol; however more positive diagnoses resulted from the GTN protocol (p = 0.0013). 47% of patients achieved a diagnosis with tilt testing. We were able to correlate a subsequent spontaneous syncope to tilt result in 36 patients (18%). Heart rate during a spontaneous event was similar to that obtained during tilt testing (± 10%) in 55% of cases. Sensitivities for combined protocols, adenosine, GTN, and drug-free protocols were 50%, 50%, 100%, and 21%, respectively. Specificities were 85%, 100%, 75%, and 71%, respectively.A high diagnosis rate for unexplained syncope can be achieved with tilt testing. The GTN protocol resulted in significantly more diagnoses than the other compared protocols with good sensitivity and adequate specificity. Sensitivity of the drug-free tilt test was lower than drug-augmented tilt testing.

Efficacy of permanent pacing in the management of high-risk patients with long QT syndrome.

From the international long QT syndrome (LQTS) study, 30 patients with corrected QT interval (QTc) of more than 0.44 second 1/2 were identified who had permanent pacemakers implanted for management of recurrent syncope or aborted cardiac arrest. Pacemakers were implanted on average 7 years after the onset of the first syncopal episode. Most of the patients were female (87%), the average age at implantation was 19 +/- 13 years, the mean QTc was 0.55 +/- 0.08 second, and 57% were receiving antiadrenergic treatment for LQTS when the pacemaker was placed. Using birth as the time origin, the median cardiac event rate was significantly (p less than 0.001) reduced by pacing from 0.5 to 0 events per patient per year, with 21 patients experiencing no cardiac events during an average pacemaker follow-up of 49 months per patient. In 10 patients in whom the demand atrial pacing rate was faster than the intrinsic sinus rate, the average heart rate was increased 23 beats/min (from 58 to 81 beats/min) with pacing with reduction in the QT interval from 0.59 seconds to 0.46 seconds. The beneficial effects of pacing in high-risk LQTS patients probably relate to the prevention of bradycardia, pauses, and the shortening of long QT intervals--factors that are known to be arrhythmogenic in this syndrome. Permanent cardiac pacing reduces the rate of recurrent syncopal events in high-risk LQTS patients, but it does not provide complete protection.