A Case of Ventricular Fibrillation in Masked Long-QT Syndrome Coexisting with Coronary Vasospasm.

Although long-QT syndrome (LQTS) with a normal range QT interval at rest leads to fatal ventricular arrhythmias, it is difficult to diagnose. In this article, we present a rare case of a patient who suffered a cardiac arrest and was recently diagnosed with LQTS and coronary vasospasm. A 62-year-old man with no syncopal episodes had a cardiopulmonary arrest while running. During coronary angiography, vasospasm was induced and we prescribed coronary vasodilators, including calcium channel blockers. An exercise stress test was performed to evaluate the effect of medications and accidentally unveiled exercise-induced QT prolongation. He was diagnosed with LQTS based on diagnostic criteria. Pharmacotherapy and an implantable cardioverter defibrillator were used for his medical management. It is extremely rare for LQTS and coronary vasospasm to coexist. In cases of exercise-induced arrhythmic events, the exercise stress test might be helpful to diagnose underlying disease.

International Cohort of Neonatal Timothy Syndrome.

INTRODUCTION: Timothy syndrome (TS) is an extremely rare, multisystem disorder classically associated with long QT, syndactyly, ventricular arrhythmias, and hypoglycaemia. A neonatal diagnosis allows maximal medical and device therapy to be implemented to avoid malignant arrhythmias and sudden cardiac death. METHODS: This was a retrospective case series study of type I TS (TS1) patients using data from the Timothy Syndrome Foundation's international registry, encompassing patients with a genetic diagnosis (CACNA1C variant G406R in exon 8A) recruited over a 28-year period. RESULTS: Forty-four cases of TS1 were included (26 male; 60%). Mean gestational age (GA) was 35.6 weeks (range 28 weeks - term), with 43% of patients born less than 37 weeks GA. In TS1 patients presenting with foetal bradycardia, mean GA was significantly lower (34.2 weeks, p < 0.05). Foetal bradycardia secondary to atrioventricular block was present in 20 patients (45%), resulting in premature delivery in 14 patients (32%). Fifteen patients (34%) were diagnosed with TS1 as neonates. Long QT at birth helped secure a diagnosis in 25 patients (57%). Syndactyly was seen in most patients (n = 40, 91%). Twenty patients died, with an average age of death of 2.3 years (range 1 month-6 years). Of the 7 patients who died before the first year of life (16%), the average age of death was 2.5 months. CONCLUSION: TS is associated with high early mortality. TS should be considered in paediatric patients presenting with long QT and syndactyly. Recognition of TS in the neonatal period allows for early intervention to prevent life-threatening arrhythmias.

Takotsubo Cardiomyopathy Presenting with QT Prolongation and Torsade de Pointes in a Patient with Coronavirus Disease 2019.

Coronavirus disease 2019 (COVID-19) is associated with cardiovascular complications; however, Takotsubo cardiomyopathy (TCM) with QT prolongation and Torsade de pointes has been reported only rarely. We present a case of TCM after QT prolongation and Torsade de pointes. A 58-year-old woman was admitted because of COVID-19-related pneumonia. Seven days after admission, she developed sudden loss of consciousness without any indication of cardiovascular disease. A monitoring electrocardiogram indicated Torsade de pointes and a prolonged QT interval. Emergency cardiac catheterization revealed TCM. She was treated with favipiravir and steroids, followed by rehabilitation, and her condition improved. To detect asymptomatic TCM, routine electrocardiography screening should be considered for patients with COVID-19.

Torsade de pointes secondary to long QT syndrome after intragastric balloon placement. A rare but severe complication.

The obesity pandemic is becoming one of the most prevalent diseases nowadays. There is a wide spectrum of treatment, ranging from hygienic-dietary measures to bariatric surgery. Endoscopic intragastric balloon placement is becoming increasingly more frequent, due to its technical simplicity, safety and short-term success(1). Although complications are rare some can be severe, so pre-endoscopic evaluation must be carried out carefully. A 43-year-old woman with a history of grade I obesity (BMI 32.7) had an Orbera® intragastric balloon implanted successfully. After the procedure she presented frequent nausea and vomiting, partially controlled with antiemetics. She attended the Emergency Department(ED) with a persistent emetic syndrome - oral intolerance and short-term loss of consciousness(syncope), for which she was admitted. Lab tests showed metabolic alkalosis with severe hypokalemia(K+ 1.8mmol/L), so fluid therapy was initiated for hydroelectrolytic replacement. During the patient's stay in the ED, two episodes of polymorphic ventricular tachychardia "Torsades de Pointes" (PVT-TDP) occurred, leading to cardiac arrest and requiring electrical cardioversion to restore sinus rhythm, in addition to a temporary pacemaker placement. Telemetry showed a corrected QT interval of >500ms, compatible with Long QT Syndrome(LQTS). Once the patient was hemodynamically stabilized a gastroscopy was performed. The intragastric balloon located in the fundus was removed using an extraction kit, puncturing and aspirating 500ml of saline solution, and extracting the collapsed balloon without any complications. The patient achieved an adequate oral intake afterwards, and no recurrence of emetic episodes were noticed. Previous ECGs revealed a prolonged QT interval and a genetic study confirmed a congenital type 1 LQTS. Treatment was initiated with beta-blockers and a bicameral automatic defibrillator was implanted in order to prevent recurrences. Intragastric balloon placement is generally a safe procedure, serious complications present in 0.70% of cases(2). It is essential to have a proper pre-endoscopic evaluation, including patient's medical history and comorbidities. Episodes of PVT-TDP may present precipitated by certain medications (eg. metoclopramide) or hydroelectrolytic imbalances (eg, hypokalemia)(3). A standardized evaluation of ECG before intragastric balloon placement may be useful to prevent these rare but serious complications.

Cohort study to assess the prevalence of prolonged QT and arrhythmias in critically ill patients during the early phase of the COVID-19 pandemic.

INTRODUCTION: Patients with SARS-CoV-2 infection may present cardiovascular involvement including myocarditis, arrhythmias and QT interval prolongation. Our objective was to evaluate the impact of COVID-19 and its treatment on ventricular repolarization and development of arrhythmias in critically ill patients. METHODS: Retrospective cohort study of critically ill COVID-19 patients during a 3-month period in whom at least one ECG was available. Relevant clinical data and specific treatment administered for COVID-19 were recorded. Prolonged QTc was considered prolonged when it measured ≥ 460 ms in women and ≥450 ms in men. The incidence and type of arrhythmias during the same period were recorded. RESULTS: A total of 77 patients with a mean age of 62 ±â€¯13 years, 20 women and 57 men, were evaluated. Sixty percent of the patients were hypertensive, 52% had a BMI > 30, and 70% developed acute renal failure during admission. Some 56% of the patients presented QTc prolongation. Forty-four percent presented some type of arrhythmia during their stay in the ICU, 21% of which were atrial arrhythmias. Overall mortality was 53%, with no differences between patients with or without prolonged QTc. CONCLUSIONS: In our series, a high proportion of critical patients with COVID-19 presented prolonged QTc and arrhythmias. The factors involved have been related to the elevation of cardiac biomarkers, the myocardial involvement of the virus and concomitant medication received in the ICU.

Risk stratification of sudden cardiac death: a review.

Sudden cardiac death (SCD) is responsible for several millions of deaths every year and remains a major health problem. To reduce this burden, diagnosing and identification of high-risk individuals and disease-specific risk stratification are essential. Treatment strategies include treatment of the underlying disease with lifestyle advice and drugs and decisions to implant a primary prevention implantable cardioverter-defibrillator (ICD) and perform ablation of the ventricles and novel treatment modalities such as left cardiac sympathetic denervation in rare specific primary electric diseases such as long QT syndrome and catecholaminergic polymorphic ventricular tachycardia. This review summarizes the current knowledge on SCD risk according to underlying heart disease and discusses the future of SCD prevention.

Stroke-Related Visceral Alterations: A Voxel-Based Neuroanatomic Localization Study.

OBJECTIVE: Functional and morphologic changes in extracranial organs can occur after acute brain injury. The neuroanatomic correlates of such changes are not fully known. Herein, we tested the hypothesis that brain infarcts are associated with cardiac and systemic abnormalities (CSAs) in a regionally specific manner. METHODS: We generated voxelwise p value maps of brain infarcts for poststroke plasma cardiac troponin T (cTnT) elevation, QTc prolongation, in-hospital infection, and acute stress hyperglycemia (ASH) in 1,208 acute ischemic stroke patients prospectively recruited into the Heart-Brain Interactions Study. We examined the relationship between infarct location and CSAs using a permutation-based approach and identified clusters of contiguous voxels associated with p < 0.05. RESULTS: cTnT elevation not attributable to a known cardiac reason was detected in 5.5%, QTc prolongation in the absence of a known provoker in 21.2%, ASH in 33.9%, and poststroke infection in 13.6%. We identified significant, spatially segregated voxel clusters for each CSA. The clusters for troponin elevation and QTc prolongation mapped to the right hemisphere. There were 3 clusters for ASH, the largest of which was in the left hemisphere. We found 2 clusters for poststroke infection, one associated with pneumonia in the left and one with urinary tract infection in the right hemisphere. The relationship between infarct location and CSAs persisted after adjusting for infarct volume. INTERPRETATION: Our results show that there are discrete regions of brain infarcts associated with CSAs. This information could be used to bootstrap toward new markers for better differentiation between neurogenic and non-neurogenic mechanisms of poststroke CSAs. ANN NEUROL 2023;94:1155-1163.

Genetic variant annotation scores in congenital long QT syndrome.

BACKGROUND: Congenital Long QT Syndrome (LQTS) is a hereditary arrhythmic disorder. We aimed to assess the performance of current genetic variant annotation scores among LQTS patients and their predictive impact. METHODS: We evaluated 2025 patients with unique mutations for LQT1-LQT3. A patient-specific score was calculated for each of four established genetic variant annotation algorithms: CADD, SIFT, REVEL, and PolyPhen-2. The scores were tested for the identification of LQTS and their predictive performance for cardiac events (CE) and life-threatening events (LTE) and then compared with the predictive performance of LQTS categorization based on mutation location/function. Score performance was tested using Harrell's C-index. RESULTS: A total of 917 subjects were classified as LQT1, 838 as LQT2, and 270 as LQT3. The identification of a pathogenic variant occurred in 99% with CADD, 92% with SIFT, 100% with REVEL, and 86% with PolyPhen-2. However, none of the genetic scores correlated with the risk of CE (Harrell's C-index: CADD = 0.50, SIFT = 0.51, REVEL = 0.50, and PolyPhen-2 = 0.52) or LTE (Harrell's C-index: CADD = 0.50, SIFT = 0.53, REVEL = 0.54, and PolyPhen-2 = 0.52). In contrast, high-risk mutation categorization based on location/function was a powerful independent predictor of CE (HR = 1.88; p < .001) and LTE (HR = 1.89, p < .001). CONCLUSION: In congenital LQTS patients, well-established algorithms (CADD, SIFT, REVEL, and PolyPhen-2) were able to identify the majority of the causal variants as pathogenic. However, the scores did not predict clinical outcomes. These results indicate that mutation location/functional assays are essential for accurate interpretation of the risk associated with LQTS mutations.

Association Between Syncope Trigger Type and Risk of Subsequent Life-Threatening Events in Patients With Long QT Syndrome.

Importance: Syncope is the most powerful predictor for subsequent life-threatening events (LTEs) in patients with congenital long QT syndrome (LQTS). Whether distinct syncope triggers are associated with differential subsequent risk of LTEs is unknown. Objective: To evaluate the association between adrenergic (AD)- and nonadrenergic (non-AD)-triggered syncopal events and the risk of subsequent LTEs in patients with LQT types 1 to 3 (LQT1-3). Design, Setting, and Participants: This retrospective cohort study included data from 5 international LQTS registries (Rochester, New York; the Mayo Clinic, Rochester, Minnesota; Israel, the Netherlands, and Japan). The study population comprised 2938 patients with genetically confirmed LQT1, LQT2, or LQT3 stemming from a single LQTS-causative variant. Patients were enrolled from July 1979 to July 2021. Exposures: Syncope by AD and non-AD triggers. Main Outcomes and Measures: The primary end point was the first occurrence of an LTE. Multivariate Cox regression was used to determine the association of AD- or non-AD-triggered syncope on the risk of subsequent LTE by genotype. Separate analysis was performed in patients with ß-blockers. Results: A total of 2938 patients were included (mean [SD] age at enrollment, 29 [7] years; 1645 [56%] female). In 1331 patients with LQT1, a first syncope occurred in 365 (27%) and was induced mostly with AD triggers (243 [67%]). Syncope preceded 43 subsequent LTEs (68%). Syncopal episodes associated with AD triggers were associated with the highest risk of subsequent LTE (hazard ratio [HR], 7.61; 95% CI, 4.18-14.20; P < .001), whereas the risk associated with syncopal events due to non-AD triggers was statistically nonsignificant (HR, 1.50; 95% CI, 0.21-4.77; P = .97). In 1106 patients with LQT2, a first syncope occurred in 283 (26%) and was associated with AD and non-AD triggers in 106 (37%) and 177 (63%), respectively. Syncope preceded 55 LTEs (56%). Both AD- and non-AD-triggered syncope were associated with a greater than 3-fold increased risk of subsequent LTE (HR, 3.07; 95% CI, 1.66-5.67; P ≤ .001 and HR, 3.45, 95% CI, 1.96-6.06; P ≤ .001, respectively). In contrast, in 501 patients with LQT3, LTE was preceded by a syncopal episode in 7 (12%). In patients with LQT1 and LQT2, treatment with ß-blockers following a syncopal event was associated with a significant reduction in the risk of subsequent LTEs. The rate of breakthrough events during treatment with ß-blockers was significantly higher among those treated with selective agents vs nonselective agents. Conclusion and Relevance: In this study, trigger-specific syncope in LQTS patients was associated with differential risk of subsequent LTE and response to ß-blocker therapy.

Increased ventricular ectopy precedes Torsades de Pointes in patients with prolonged QT.

OBJECTIVE: Torsades de Pointes (TdP) is a potentially lethal ventricular tachydysrhythmia. Prolonged heartrate corrected QT interval (QTc) predicts TdP; however, with poor specificity. We performed this study to identify other predictors of TdP among patients with prolonged QTc. METHODS: We performed a retrospective case control study with 2:1 matching at an urban academic hospital. We searched our hospital electrocardiogram (ECG) database for tracings with heartrate ≤ 60, QTc ≥ 500, and QRS < 120, followed by a natural language search for electronic records with "Torsades," "polymorphic VT," or similar to identify TdP cases from 2005 to 19. We identified controls from a similar ECG database search matching for QTc, heartrate, age, and sex. We compared cardiologic and historical factors, medications, laboratory values, and ECG measurements including ectopy using univariate statistics. For those cases with saved telemetry strips that included preceding beats or TdP onset, we compared ectopy and TdP onset characteristics between the ECG and telemetry strips using mixed linear modeling. RESULTS: Seventy-five cases including 50 with telemetry strips and 150 controls were included. Historical, pharmacologic, laboratory, and cardiologic testing results were similar between cases and controls. The proportion of telemetry tracings with premature ventricular contractions (PVC's) preceding TdP was 0.78 compared to 0.16 for case ECG's (difference 0.62(95%CI 0.44-0.75)) and 0.10 for control ECGs (difference 0.68(95%CI 0.56-0.80)). Average telemetry heartrate was 72 and QTc 549 immediately preceding TdP, similar to the ECG values. CONCLUSIONS: Clinical factors don't differentiate patients with long QTc who develop TdP, however, an increase in PVC's in patients with prolonged QTc may usefully predict imminent TdP.

KCNH2 variants in a family with epilepsy and long QT syndrome: A case report and literature review.

OBJECTIVE: Genes associated with Long QT syndromes (LQTS), such as KCNQ1, KCNH2, and SCN5A, are common causes of epilepsy. The Arg 744* variant of KCNH2 has been previously reported in people with epilepsy or LQTS, but none of these patients were reported to simultaneously suffer from epilepsy and LQTS. Herein, we report the case of a family with epilepsy and cardiac disorders. METHOD: The proband, a 25-year-old woman, with a family history of epilepsy and LQTS was followed at West China Hospital. The proband experienced her first seizure at the age of seven. Video electroencephalograms (vEEGs) showed epileptic discharges. Her 24-h dynamic electrocardiograms 2 (ECGs) showed QTc prolongation. The proband's mother, who is 50 years old, had her first generalized tonic-clonic seizure (GTCS) at the age of 18 years old. After she gave birth at the age of 25, the frequency of seizures increased, so antiepileptic therapy was initiated. When she was 28 years old, she complained of palpitations and syncope for the first time, and QTc prolongation was detected on her 24-h dynamic ECGs. The proband's grandmother also had complaints of palpitations and syncope at the age of 73. Her 24-h dynamic ECGs indicated supraventricular arrhythmia, with the lowest heart rate being 41 bpm, so she agreed to a pacemaker. Considering the young patient's family history, blood samples of the patient and her parents were collected for genetic analysis. RESULTS: A heterozygous variant of KCNH2 [c.2230 (exon9) C>T, p. Arg744Ter, 416, NM_000238, rs189014161] was found in the proband and her mother. According to the guidelines of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology, we classified the KCNH2 variant as pathogenic. SIGNIFICANCE: This study expands the clinical phenotype of the Arg 744* KCNH2 pathogenic variant. In the context of channelopathies, because of the genetic susceptibility of the brain and the heart, the risk of comorbidity should be considered. This also indicates the importance of precise antiepileptic drug (AED) management and regular ECG monitoring for patients with channelopathies.

Whole-exome sequencing and electrophysiological study reveal a novel loss-of-function mutation of KCNA10 in epinephrine provoked long QT syndrome with familial history of sudden cardiac death.

Congenital long QT syndrome (LQTS) is one type of inherited fatal cardiac arrhythmia that may lead to sudden cardiac death (SCD). Mutations in more than 16 genes have been reported to be associated with LQTS, whereas the genetic causes of about 20% of cases remain unknown. In the present study, we investigated a four-generation pedigree with familial history of syncope and SCD. The proband was a 33-year-old young woman who experienced 3 episodes of syncope when walking at night. The electrocardiogram revealed a markedly epinephrine-provoked prolonged QT interval (QT = 468 ms, QTc = 651 ms) but no obvious arrhythmia in the resting state. Three family members have died of suspected SCD. Whole-exome sequencing and bioinformatic analysis based on pedigree revealed that a novel missense mutation KCNA10 (c.1397G＞A/Arg466Gln) was the potential genetic lesion. Sanger sequencing was performed to confirm the whole-exome sequencing results. This mutation resulted in the KV1.8 channel amino acid residue 466 changing from arginine to glutamine, and the electrophysiological experiments verified it as a loss-of-function mutation of KV1.8, which reduced the K+ currents of KV1.8 and might result in the prolonged QT interval. These findings suggested that KCNA10 (c.1397G＞A) mutation was possibly pathogenic in this enrolled LQTS family, and may provide a new potential genetic target for diagnosis and counseling of stress-related LQTS families as well as the postmortem diagnosis of SCD.

Long-QT Syndrome with Peripartum Cardiomyopathy Causing Fatal Ventricular Arrhythmia after Delivery.

Although rare, long QT syndrome (LQTS) and peripartum cardiomyopathy (PPCM) are the major causes of maternal cardiovascular death. We herein present a case study of a 23-year-old woman with LQTS, pregnancy-induced hypertension, and PPCM. During the postpartum period, her left ventricular systolic function had severely decreased, requiring the administration of loop diuretics. Diuretics cause several changes in the circulating blood volume, electrolyte balance, and hormonal status during pregnancy, delivery, and the peripartum period. Extreme QTc prolongation and fatal ventricular arrhythmia require frequent defibrillation. For the patient in this study, we corrected her electrolyte abnormality, and eventually, we controlled the arrhythmia by administering a ß-blocker and Na-channel blocker. Although the arrhythmia subsided, she continued on medication after discharge to prevent the recurrence of fatal arrhythmia. In conclusion, close attention should be paid to patients with LQTS, especially when some changes that may lead to QTc prolongation could occur during the peripartum period.

Phenotypes of Overdiagnosed Long QT Syndrome.

BACKGROUND: Long QT syndrome (LQTS) predisposes individuals to arrhythmic syncope or seizure, sudden cardiac arrest, or sudden cardiac death (SCD). Increased physician and public awareness of LQTS-associated warning signs and an increase in electrocardiographic screening programs may contribute to overdiagnosis of LQTS. OBJECTIVES: This study sought to identify the diagnostic miscues underlying the continued overdiagnosis of LQTS. METHODS: Electronic medical records were reviewed for patients who arrived with an outside diagnosis of LQTS but were dismissed as having normal findings subsequently. Data were abstracted for details on referral, clinical history, and both cardiologic and genetic test results. RESULTS: Overall, 290 of 1,841 (16%) patients with original diagnosis of LQTS (174 [60%] female; mean age at first Mayo Clinic evaluation, 22 ± 14 years; mean QTc interval, 427 ± 25 milliseconds) were dismissed as having normal findings. The main cause of LQTS misdiagnosis or overdiagnosis was a prolonged QTc interval secondary to vasovagal syncope (n = 87; 30%), followed by a seemingly positive genetic test result for a variant in 1 of the main LQTS genes (n = 68; 23%) that was ultimately deemed not to be of clinical significance. Furthermore, patients received misdiagnoses because of a positive family history of SCD that was deemed unrelated to LQTS (n = 46; 16%), isolated/transient QT prolongation (n = 44; 15%), or misinterpretation of the QTc interval as a result of inclusion of the U-wave (n = 40, 14%). CONCLUSIONS: Knowing the 5 main determinants of discordance between a previously rendered diagnosis of LQTS and full diagnostic reversal or removal (vasovagal syncope, "pseudo"-positive genetic test result in LQTS-causative genes, family history of SCD, transient QT prolongation, and misinterpretation of the QTc interval) increases awareness and provides critical guidance to reduce this burden of overdiagnosed LQTS.

Sustained heart rate-corrected QT prolongation during recovery from hypoglycaemia in people with type 1 diabetes, independently of recovery to hyperglycaemia or euglycaemia.

AIM: To investigate changes in cardiac repolarization abnormalities (heart rate-corrected QT [QTc ] [primary endpoint], T-wave abnormalities) and heart-rate variability measures in people with type 1 diabetes during insulin-induced hypoglycaemia followed by recovery hyperglycaemia versus euglycaemia. METHODS: In a randomized crossover study, 24 individuals with type 1 diabetes underwent two experimental clamps with three steady-state phases during electrocardiographic monitoring: (1) a 45-minute euglycaemic phase (5-8 mmol/L), (2) a 60-minute insulin-induced hypoglycaemic phase (2.5 mmol/L), and (3) 60-minute recovery in either hyperglycaemia (20 mmol/L) or euglycaemia (5-8 mmol/L). RESULTS: All measured markers of arrhythmic risk indicated increased risk during hypoglycaemia. These findings were accompanied by a decrease in vagal tone during both hyperglycaemia and euglycaemia clamps. Compared with baseline, the QTc interval increased during hypoglycaemia, and 63% of the participants exhibited a peak QTc of more than 500 ms. The prolonged QTc interval was sustained during both recovery phases with no difference between recovery hyperglycaemia versus euglycaemia. During recovery, no change from baseline was observed in heart-rate variability measures. CONCLUSIONS: In people with type 1 diabetes, insulin-induced hypoglycaemia prolongs cardiac repolarization, which is sustained during a 60-minute recovery period independently of recovery to hyperglycaemia or euglycaemia. Thus, vulnerability to serious cardiac arrhythmias and sudden cardiac death may extend beyond a hypoglycaemic event, regardless of hyperglycaemic or euglycaemic recovery.

Relationship of the T-wave Tpeak-Tend interval with conduction system disorders in arterial hypertension.

PURPOSE: The Tpeak-Tend interval of the T wave has emerged as a new electrocardiographic marker of increased transmural dispersion of ventricular repolarization. We aimed to determine the presence of cardiac conduction system disorders in patients with systemic arterial hypertension (SAH) who have altered Tpeak-Tend interval of the T wave. METHODS: The 67 patients with SAH were divided into two groups. Those with prolonged (≥ 77 ms) Tpeak-Tend intervals, 21 (31%) patients were in the study group. Those with normal (< 77 ms) Tpeak-Tend intervals, 46 (69%) patients were in the control group. Alteration of ventricular repolarization manifested as a prolongation of the Tpeak-Tend interval was detected by computerized electrocardiographic analysis tools. RESULTS: The median value of QRS complex duration was significantly wider in the study group as compared to the control group (110 ± 12 ms vs. 94 ± 8 ms p < 0.001). There was a significantly greater incidence of left anterior hemiblock in the study group (14% vs. 0% p < 0.04). The median value of the QTc interval was significantly greater in the study group (440 ± 26 vs. 422 ± 15 p < 0.01). There was a significantly greater incidence of patients with prolonged QTc interval in the study group (33% vs. 11% p < 0.02). The median value of the Tpeak-Tend interval was significantly greater in the study group (84 ± 5 ms vs. 65 ± 4 ms p < 0.001), as well as, the Tpeak-Tend/QTc ratio in the study group (0.19 ± 0.1 vs. 0.16 ± 0.1 p < 0.001). CONCLUSION: There is a significantly greater ventricular repolarization disorders and abnormalities of the cardiac conduction system in SAH patients who possess altered Tpeak-Tend interval of the T wave.

OBJETIVO: El intervalo Tpico-Tfinal de la onda T es un marcador electrocardiográfico de la dispersión transmural aumentada de la repolarización ventricular. Investigamos la presencia de trastornos del sistema de conducción cardíaca en pacientes con hipertensión arterial sistémica (HA) que poseen alterado el intervalo Tpico-Tfinal de la onda T. MÉTODOS: Los 67 pacientes con HA fueron divididos en dos grupos. Aquellos con intervalos de Tpico-Tfinal prolongados (≥ 77 ms), 21 (31%) pacientes (grupo de estudio). Aquellos con intervalos normales (< 77 ms) Tpico-Tfinal, 46 (69%) pacientes (grupo control). Los intervalos Tpico-Tfinal fueron medidos por herramientas de análisis electrocardiográfico computarizado. RESULTADOS: El valor mediano de la duración del complejo QRS fue significativamente más amplio en el grupo de estudio (110 ± 12 ms vs. 94 ± 8 ms p < 0.001). Hubo una incidencia significativamente mayor de hemibloqueo anterior izquierdo en el grupo de estudio (14% vs. 0% p < 0.04). El valor mediano del intervalo QTc fue significativamente mayor en el grupo de estudio (440 ± 26 vs. 422 ± 15 p < 0.01). Hubo una incidencia significativamente mayor de pacientes con intervalo QTc prolongado en el grupo de estudio (33% vs. 11% p < 0.02). El valor mediano del intervalo Tpico-Tfinal fue significativamente mayor en el grupo de estudio (84 ± 5 ms vs. 65 ± 4 ms p < 0.001), así como el cociente Tpico-Tfinal/QTc (0.19 ± 0.1 vs. 0.16 ± 0.1 p < 0.001). CONCLUSIÓN: Existe una alteración de la repolarización ventricular significativamente mayor y anomalías del sistema de conducción cardíaca en pacientes con HA que poseen alteración del intervalo Tpico-Tfinal de la onda T.

A QTc risk score in patients with obstructive sleep apnea.

INTRODUCTION: Patients with obstructive sleep apnea (OSA) are at risk for QTc prolongation, a known risk factor for increased mortality. The pro-QTc score can help identify individuals at increased risk for mortality associated with increased QTc however, it has not been evaluated in patients with OSA. The goal of this study was to evaluate the pro-QTc score in patients with OSA. METHODS: Medical records of patients undergoing a sleep study at our sleep center from February 2012 to August 2020 were analyzed. Presence or absence of OSA was determined by polysomnography. The pro-QTc score was calculated with 1 point assigned for each of the following: female sex, QT-prolonging diagnoses and conditions, QT-prolonging electrolyte abnormalities, and medications with known risk for QT-prolongation. Mortality was determined from the electronic medical record of an integrated healthcare system. RESULTS: There were 2246 patients (age 58 ± 15 years, 54% male, 82 dead) with OSA and 421 patients (age 54 ± 18 years, 43% male, 18 dead) without OSA. Of those with OSA, 1628 (72.5%) had at least one risk factor for QTc prolongation. A higher pro-QTc score was associated with greater mortality in patients with OSA (HR 1.48 per pro-QTc score, p < 0.001, 95% CI 1.3-1.7) but not in patients without OSA (HR 1.25 per pro-QTc score, p = 0.30, 95% CI 0.82-1.9), after adjusting for age, body mass index (BMI), and smoking status. CONCLUSION: In patients with OSA, a higher pro-QTc score was associated with greater mortality.

Right ventricular epicardial arrhythmogenic substrate in long-QT syndrome patients at risk of sudden death.

AIMS: The long-QT syndrome (LQTS) represents a leading cause of sudden cardiac death (SCD). The aim of this study was to assess the presence of an underlying electroanatomical arrhythmogenic substrate in high-risk LQTS patients. METHODS AND RESULTS: The present study enrolled 11 consecutive LQTS patients who had experienced frequent implantable cardioverter-defibrillator (ICD discharges triggered by ventricular fibrillation (VF). We acquired electroanatomical biventricular maps of both endo and epicardial regions for all patients and analyzed electrograms sampled from several myocardial regions. Abnormal electrical activities were targeted and eliminated by the means of radiofrequency catheter ablation. VF episodes caused a median of four ICD discharges in eleven patients (6 male, 54.5%; mean age 44.0 ± 7.8 years, range 22-53) prior to our mapping and ablation procedures. The average QTc interval was 500.0 ± 30.2 ms. Endo-epicardial biventricular maps displayed abnormally fragmented, low-voltage (0.9 ± 0.2 mV) and prolonged electrograms (89.9 ± 24.1 ms) exclusively localized in the right ventricular epicardium. We found electrical abnormalities extending over a mean epicardial area of 15.7 ± 3.1 cm2. Catheter ablation of the abnormal epicardial area completely suppressed malignant arrhythmias over a mean 12 months of follow-up (median VF episodes before vs. after ablation, 4 vs. 0; P = 0.003). After the procedure, the QTc interval measured in a 12-lead ECG analysis shortened to a mean of 461.8 ± 23.6 ms (P = 0.004). CONCLUSION: This study reveals that, among high-risk LQTS patients, regions localized in the epicardium of the right ventricle harbour structural electrophysiological abnormalities. Elimination of these abnormal electrical activities successfully prevented malignant ventricular arrhythmia recurrences.

Effect of antipsychotic use by patients with schizophrenia on deceleration capacity and its relation to the corrected QT interval.

OBJECTIVE: Schizophrenia patients treated with antipsychotics are at higher risk of sudden cardiac death. Decreased deceleration capacity (DC) of the heart rate is an accurate predictor of cardiac mortality. We evaluated the risk of sudden cardiac death due to antipsychotic use by assessing DC and examining the association between DC and the corrected QT interval (QTc) in schizophrenia patients. METHODS: We measured the DC and QTc of 138 schizophrenia patients. We then compared the DC of 86 age- and sex-matched healthy controls with that of 86 schizophrenia patients. We investigated the correlation of DC of approximately 138 schizophrenia patients with prescribed doses of antipsychotics using linear regression analysis. We compared the DC of schizophrenia patients with and without prolonged QT intervals. RESULTS: We found DC significantly differed between schizophrenia patients on antipsychotic medication and healthy controls. Additionally, DC was negatively correlated with antipsychotic use, especially chlorpromazine, zotepine, olanzapine and clozapine, in a dose-dependent manner. There was no significant association between DC and the QTc. CONCLUSION: Assessing DC could facilitate monitoring and identification of increased risk of cardiac mortality in patients with schizophrenia that take antipsychotics. Assessing both DC and the QTc may enhance the accuracy of predicting sudden cardiac death.