Penicillamine-induced polymyositis with complete heart block

Complete heart block with severe Adams-Stokes attacks and polymyositiswas observed in a 69-year-old man following 6 weeks penicillaminetreatment for suspected rheumatoid arthritis. After drug withdrawalthe muscle enzymes and the cardiac rhythm gradually normalized,only leaving a right bundle branch block. Although this is the first report to show that severe cardiacdamage associated with penicillamine-induced polymyositis isa potentially reversible condition, the severity of the threecases reported so far warrants close observation for cardiacinvolvement in patients with penicillamine-induced polymyositis.     

Torsades de pointes during complete atrioventricular block: Genetic factors and electrocardiogram correlates

INTRODUCTION:

Atrioventricular (AV) block is infrequently associated with QT prolongation and torsades de pointes (TdP). It was hypothesized that patients with AV block-mediated QT-related arrhythmia may have latent congenital long QT syndrome or a vulnerable genetic polymorphism.

METHODS:

Eleven patients with complete AV block and TdP were prospectively identified. Patients underwent assessment, resting electrocardiography and telemetry at baseline, during AV block and pre-TdP. Genetic testing of KCNH2, KCNQ1, KCNE1, KCNE2 and SCN5A was performed. Thirty-three patients with AV block without TdP were included for comparison.

RESULTS:

Genetic variants were identified in 36% of patients with AV block and TdP. Patients with AV block who developed TdP had significantly longer mean (± SD) corrected QT intervals (440±93 ms versus 376±40 ms, P=0.048) and T_peak to T_end (T_p-T_e) intervals (147±25 ms versus 94±25 ms, P=0.0001) than patients with AV block alone. In patients with a genetic variant, there was a significant increase in T_p-T_e intervals at baseline, in AV block and pre-TdP compared with those who were genotype negative. A personal or family history of syncope or sudden death was more likely observed in patients with a genetic variant.

CONCLUSIONS:

TdP in the setting of AV block may be a marker of an underlying genetic predisposition to reduced repolarization reserve. The T_p-T_e interval at baseline, in AV block and pre-TdP may predict a genetic mutation or polymorphism compromising repolarization reserve. Patients with TdP in the setting of AV block represent a phenotypic manifestation of latent congenital long QT syndrome.     

Etiology and device therapy in complete atrioventricular block in pediatric and young adult population: Contemporary review and new perspectives

Complete atrioventricular block (CAVB) is a total dissociation between the atrial and ventricular activity, in the absence of atrioventricular conduction. Several diseases may result in CAVB in the pediatric and young-adult population. Permanent right ventricular (RV) pacing is required in permanent CAVB, when the cause is neither transient nor reversible. Continuous RV apical pacing has been associated with unfavorable outcomes in several studies due to the associated ventricular dyssynchrony. This study aims to summarize the current literature regarding CAVB in the pediatric and young adult population and to explore future treatment perspectives.     

Heart rate-corrected QT interval prolongation is associated with decreased heart rate variability in patients with type 2 diabetes

We investigated the association between the heart rate-corrected QT interval (QTc interval) measured by standard electrocardiography and heart rate variability (HRV) in patients with type 2 diabetes mellitus (T2DM). From March 1, 2009, to December 12, 2009, 411 patients with T2DM who underwent resting 12-lead electrocardiography and cardiovascular autonomic function testing concurrently without the exclusion criteria were consecutively recruited in this cross-sectional study. Time- and frequency-domain HRV variables were assessed for 5 minutes by beat-to-beat HRV recording. The QT interval was corrected for the heart rate using Bazett’s formula. QTc interval measurements of >440 ms were considered abnormally prolonged. The mean age and diabetes duration were 56.3 ± 10.6 years and 9.6 ± 7.3 years, respectively. A total of 90 patients had QTc interval prolongation (21.9%). The participants with a prolonged QTc interval were older (59.4 ± 10.1 years vs 55.5 ± 10.6 years, P = .002), were more likely to be a woman (72.2% vs 51.7%, P = .001), had a higher prevalence of hypertension (46.7% vs 33.4%, P = .022), had a higher hemoglobin A1c level (8.8% ± 2.2% vs 8.2% ± 1.8%, P = .045), and had decreased values for the variables measuring HRV, except for the low frequency (LF)/high frequency (HF) ratio (total power [TP], 147.7 [74.1–335.9] ms vs 328.7 [185.7–721.7] ms, P = .002). After adjusting for multiple confounders, QTc interval prolongation was associated with the lowest quartile of the HRV parameters of TP (odds ratio [OR] = 3.99; 95% confidence interval [CI]: 2.29–6.96), HF (OR = 3.20; 95% CI: 1.84–5.58), LF (OR = 3.68; 95% CI: 2.10–6.43), standard deviation of the normal-to-normal interval (OR = 3.31; 95% CI: 1.89–5.77), and root-mean-square of the successive differences (OR = 1.98; 95% CI: 1.13–3.47) in patients with T2DM. Decreased values for the variables measuring HRV, except for the LF/HF ratio, might be associated with QTc interval prolongation in patients with T2DM.     

Cardiac metastasis of malignant melanoma: a rare cause of complete atrioventricular block.

Malignant melanoma has an aggressive biological behaviour and a high rate of cardiac involvement. As shown from post-mortem studies, metastases of melanoma can involve any organ and cardiac metastases are frequent. This report describes a case of widespread malignant melanoma in a patient with clinical presentation of complete atrioventricular (AV) block. Thorax CT and transthoracic echocardiography revealed a mass involving the conduction system. By VDD permanent pacing (atrial synchronous ventricular pacing), haemodynamic stability was maintained and the patient remains under follow-up receiving chemo-immunotherapy. In the retrospective analysis of the patient's records, we realized that the AV conduction delay had been progressing for at least 7 months. Cardiac metastasis of malignant melanoma is a common finding and can proceed in the absence of overt clinical manifestations. Therefore, the clinician should be alert to the development of cardiac signs and symptoms in a metastatic melanoma patient and should perform a detailed cardiac examination to exclude cardiac metastasis of the tumour.     

Long QT Interval and Ventricular Tachycardia of “Torsade de Pointe” Type in Hypothyroidism

ABSTRACT We have observed two patients with long QT interval, ventricular tachycardias of “torsade de pointe” type and repeated ventricular fibrillation episodes, who also turned out to have significant hypothyroidism. This was suspected from the clinical picture in one patient and after haematological test in the other. In addition to hypothyroidism, both patients had associated factors which may have contributed to the development of the arrhythmia. After having reached an euthyroid state, both patients normalized their QT intervals, were relieved from earlier symptoms of cardiac arrhythmias and exhibited no longer any documented arrhythmia. Before thyroid substitution, both patients had marked signs of delayed ventricular repolarization even by invasive electrophysiological methods. Our observations indicate that hypothyroidism should be considered a possible primary cause in cases with long QT syndrome (LQTS). Furthermore, the possibility of LQTS in patients with hypothyroidism should be considered.     

Tachycardia after pacemaker implantation in a patient with complete atrioventricular block.

The atrioventricular (AV) node allows ante- and retrograde conduction between atria and ventricles. It is commonly assumed that these AV nodal conduction properties go hand in hand. However, ante- and retrograde AV conduction can be completely independent from each other in individual patients. We report about a patient with permanent AV block III degrees requiring implantation of a pacemaker. As soon as a dual-chamber device was connected to the implanted leads, a tachycardia started at the maximum tracking rate, which was subsequently reprogrammed from 120 to 170 bpm. Non-invasive electrophysiologic testing showed that this patient demonstrated 1:1 ventriculoatrial (VA) conduction up to 170 bpm leading to endless loop tachycardia (ELT) while the antegrade AV block III degrees persisted. This case impressively illustrates that one has to take into account that patients with antegrade AV block III degrees may still have a high VA conduction capacity leading to ELT. Dual-chamber devices therefore have to be programmed accordingly, activating dedicated reactions after ventricular premature beats and automatic ELT detection and termination algorithms.     

老年心力衰竭患者心电图校正QT间期改变及相关因素分析

目的 探讨老年心力衰竭患者心电图校正的QT间期(QTc)变化及其延长的相关因素.方法 选取2018年1月至2021年1月于无锡市惠山区第二人民医院收治的左心功能不全,但窦性心律、无明确的束支传导阻滞532例患者的临床资料.所有患者治疗前均完成心功能评估及心电图和心脏超声检查.按QTc≥440 ms和QTc<440 ms...     

获得性QT间期延长伴尖端扭转型室性心动过速52例临床分析

目的 总结获得性QT间期延长伴尖端扭转型室性心动过速(扭转型室速)患者的危险因素、心电图特征、治疗方法,为临床医生正确识别和处理提供帮助.方法以"扭转型室速"及"QT间期延长"检索阜外心血管病医院1990至2010年病历库,统计获得性扭转型室速患者的临床资料.结果总计52例获得性扭转型室速,其中67.3%有基础心脏病,59.6%存在电解质紊乱,36.5%应用利尿剂,28.8%应用延长QT间期的抗心律失常药.治疗前后平均QTc分别为(571±93)ms及(456±50)ms,所有患者均经补钾、补镁治疗,32.7%应用异丙肾上腺素,13.5%接受临时起搏治疗.结论获得性扭转型室速多发生于电解质紊乱及应用延长QT间期药物的患者.高危患者应监测心电图及QTc变化,注意有预警价值的表现,有助于早期识别并正确治疗.

Abstract：

Objective Risk factors, ECG characteristics and treatment options of patients with Torsade de Points associated with acquired QT prolongation are summarized in this study. Method Using "torsade de points" and "QT prolongation" as the keywords to search the inpatients database from 1990 -2010 of Fuwai hospital, 52 eligible patients were included in this analysis. Results Structural heart diseases were found in 67.3% and electrolyte disorders in 59. 6% patients, 36. 5% patients received diuretic therapy and 28. 8% received antiarrhythmic drugs which might induce prolonged QT interval The mean QTc was (571 ±93)ms and (456 ±50)ms before and after treatment. All patients received potassium and magnesium supplement. Isoproterenol was used in 32. 7% patients. 13.5% patients received temporary pacing therapy. Conclusions Torsade de points and acquired QT interval prolongation was often associated with electrolyte disorders and drugs causing QT prolongation. ECG and QTc should be intensively monitored for high risk patients. Early awareness of the warning signs might contribute to early recognition and proper treatment of patients with Torsade de Points associated with acquired QT prolongation.     

Problems of heart rate correction in assessment of drug-induced QT interval prolongation

INTRODUCTION: Estimation of QT interval prolongation belongs to safety assessment of every drug. Among unresolved issues, heart rate correction of the QT interval may be problematic. This article proposes a strategy for heart rate correction in drug safety studies and demonstrates the strategy using a study of ebastine, a nonsedating antihistamine. METHODS AND RESULTS: Four-way cross-over Phase I study investigated 32 subjects on placebo, ebastine 60 mg once a day, 100 mg once a day, and terfenadine 180 mg twice a day. Repeated ECGs were obtained before each arm and after 7 days of treatment. The changes in heart rate-corrected QTc interval were investigated using (A) 20 published heart rate correction formulas, (B) a correction formula optimized by QT/RR regression modeling in all baseline data, and (C) individual corrections optimized for each subject by drug-free QT/RR regression modeling. (A) Previously published correction formulas found QTc interval increases on terfenadine. The results with ebastine were inconsistent. For instance, Bazett's and Lecocq's correction found significant QTc increase and decrease on ebastine, respectively. The results were related (absolute value(r) > 0.95) to the success of each formula (independence of drug-free QTc and RR intervals). (B) The pooled drug-free QT/RR regression found an optimized correction QTc = QT/RR(0.314). QTc interval changes on placebo, ebastine 60 mg, ebastine 100 mg, and terfenadine were -1.95 +/- 6.87 msec (P = 0.18), -3.91 +/- 9.38 msec (P = 0.053), 0.75 +/- 8.23 msec (P = 0.66), and 12.95 +/- 14.64 msec (P = 0.00025), respectively. (C) Individual QT/RR regressions were significantly different between subjects and found optimized corrections QTc = QT/RR(alpha) with alpha = 0.161 to 0.417. Individualized QTc interval changes on placebo, ebastine 60 mg, ebastine 100 mg, and terfenadine were -2.76 +/- 5.51 msec (P = 0.022), -3.15 +/- 9.17 msec (P = 0.11), -2.61 +/- 9.55 msec (P = 0.19), and 12.43 +/- 15.25 msec (P = 0.00057, respectively. Drug-unrelated QTc changes up to 4.70 +/- 8.92 msec reflected measurement variability. CONCLUSION: Use of published heart rate correction formulas in the assessment of drug-induced QTc prolongation is inappropriate, especially when the drug might induce heart rate changes. Correction formulas optimized for pooled drug-free data are inferior to the formulas individualized for each subject. Measurement imprecision and natural variability can lead to mean QTc interval changes of 4 to 5 msec in the absence of drug treatment.     

Torsade des pointes and aprindine

Aprindine was given orally to an 88-year-old patient with atrial fibrillation and ventricular premature depolarizations. The premature beats disappeared and sinus rhythm was restored on the third day of treatment. While on aprindine the QT interval was prolonged and the U wave became very prominent. The aprindine was stopped but 36 hr following the last oral dose, ventricular arrhythmia appeared with the characters of torsade des pointes. Three such episodes occurred within 24 hr. It is suggested that aprindine both eliminated the premature depolarizations and rendered the myocardium vulnerable by prolonging the QT interval. On discontinuing the medicament the premature beats reappeared while the myocardium was still vulnerable, so that torsade des pointes resulted.     

Optimal atrioventricular delay setting determined by evoked QT interval in patients with implanted stimulus-T-driven DDDR pacemakers.

Cardiac function is improved by optimizing the atrioventricular (AV) delay. An automatic optimizing function of AV delay may be necessary to achieve the most favourable haemodynamic state in paced patients. The QT interval may change when cardiac function is improved by optimizing the AV delay. The QT or stimulus-T interval is used as a sensor for rate-responsive pacemakers. Evoked (e) QT interval is measured as the time duration from the ventricular pace pulse (stimulus) and the T-sense point that is the steepest point of the intracardiac T wave (stimulus-T interval). The relationship between AV delay, eQT interval and cardiac function was studied in 10 patients (73 +/- 10 (SD) years old) with an implanted stimulus-T-driven DDDR pacemaker. Cardiac output (CO) and pulmonary capillary wedge pressure (PCWP) were measured by Swan-Ganz catheter. The AV delay was prolonged stepwise by 30 ms. Electrocardiogram event markers which indicated ventricular spike and sensed T wave were recorded, and the interval between two event markers was measured as eQT interval. When AV delay was changed from 240 ms to the AV delay at which CO was maximal (172 +/- 33 ms), eQT interval prolonged from 346 +/- 60 to 353 +/- 62 ms (P < 0.01). There was a significant positive correlation between the optimal AV delay at which CO was maximal (172 +/- 33 ms) and the optimal AV delay which was predicted from the maximum eQT interval (179 +/- 37 ms, r = 0.92, P < 0.001). When AV delay was changed from 240 ms to the predicted optimal AV delay, CO increased from 4.2 +/- 0.7 to 4.5 +/- 0.81.min-1 (P < 0.001) and PCWP was decreased from 7.1 +/- 4.0 to 5.7 +/- 3.1 mmHg (P < 0.05). In conclusion, the optimal AV delay can be predicted from the eQT interval which is sensed by an implanted pacemaker. Automatic setting of the optimal AV delay may be achieved by the QT sensor of an implanted pacemaker.     

Late-presenting complete heart block after pediatric cardiac surgery

Late presenting complete heart block after pediatric cardiac surgery is a rare complication and its management is well defined once the initial diagnosis in made timely and appropriately. In this report we described a child who underwent atrioventricular septal defect repair with a normal sinus rhythm during the postoperative period, as well as during the first 2 years of follow up.She subsequently developed complete heart block with bradycardia that required insertion of a pacemaker. Here we discuss this unusual late-presenting complication, possible risk factors, and management.     

Relationship between atrioventricular delay, QT interval and cardiac function in patients with implanted DDD pacemakers.

QT interval may change when cardiac function is improved by optimizing the atrioventricular the (AV) delay. The relationship between AV delay, QT interval and cardiac function in patients with implanted DDD pacemakers was studied in 12 patients (aged 71+/-12 SD years) with complete or high degree AV block. Cardiac output (CO) was measured using a Swan-Ganz catheter or by continuous Doppler echocardiography. The pacing rate was fixed at 70-80/min to eliminate the influence of heart rate. The AV delay was prolonged stepwise by 30 ms starting from 90 ms. All measurements were performed after 5 min of pacing. When the AV delay was prolonged, the CO and QT interval gradually increased and reached a peak, and then decreased. When the CO was increased from the minimum to the maximum value by optimizing the AV delay, the QT interval was significantly prolonged from 440+/-40 to 456+/-39 ms (P<0.002). The CO increased from 5.5+/-2.5 to 6.0+/-2.5 l x min(-1) (P<0.002) when the AV delay was changed, during which the QT interval was prolonged from the minimum to the maximum value. There was a significant positive correlation between the optimal AV delay at which CO was maximal (161+/-33 ms) and the optimal AV delay predicted from the maximum QT interval (167+/-29 ms, r=0.85, P<0.001). In conclusion, the optimal AV delay can be predicted from the QT interval.     

Predictors of in-hospital ventricular fibrillation or torsades de pointes in patients with acute symptomatic bradycardia

Severe bradyarrythmias remain as an important cause for hospital urgent admission and these patients can suffer potentially lethal complications (such as ventricular fibrillation [VF] and torsades de pointes [TdP]) between hospital admission and final therapy. Incidence and predictors of these tachyarrhythmias have not been well established. We retrospectively studied all consecutive patients (N = 243, age 75 +/- 10 years; 47% men) admitted to the emergency department of a general hospital between January 1998 and July 2000 for symptomatic bradyarrhythmia. Concomitant therapy included diuretics (25%), digitalis (10%), beta-blockers (10%), amiodarone (2%), and verapamil or diltiazem (8%). Syncope was the most frequent symptom at admission (54%). The most prevalent inclusion bradyarrhythmia was > or =second-degree AV block (82%). Eleven patients (4.5%) presented VF or TdP. Univariate predictors for these complications were previous amiodarone or diuretic intake, presentation as syncope, low serum potassium level, and longer QTc at admission. Multivariate analysis with logistic regression showed only therapy with diuretics and/or amiodarone and QTc at admission as significant predictors for TdP or VF development. Incidence of VF or TdP in patients admitted for symptomatic bradyarrhythmia is relatively important. A prolonged QTc interval and/or therapy with amiodarone or diuretics can predict their presentation.     

QT interval prolongation in association with impaired circadian variation of blood pressure and heart rate in adolescents with Type 1 diabetes.

AIMS: The aim of our study was to assess diurnal blood pressure (BP) and heart rate variability and their possible relationship to the duration of the QT interval in adolescents with Type 1 diabetes. METHODS: In 48 normotensive, normoalbuminuric diabetic adolescents, with a mean (+/- sd) age of 17.3 (+/- 4.1) years and a mean (+/- sd) diabetes duration of 8.5 (+/- 3.3) years, 24-h ambulatory BP was recorded. In addition, 24-h heart rate (HR) monitoring was performed and QT and corrected QT (QTc) intervals were estimated as indices of autonomic function. The patients were divided into two groups according to the absence of a decrease (non-dippers) or the presence of a decrease (dippers) in nocturnal diastolic BP (DBP). RESULTS: In comparison with the dippers, the non-dippers showed reduced mean 24-h HR (79.6 vs. 84.0 beats/min, P = 0.05) and reduced mean daytime HR (81.3 vs. 86.0 beats/min, P = 0.05). The QT interval was prolonged in the non-dippers (366.3 vs. 347.5 ms, P = 0.015), and end systolic (28.7 vs. 25.9 mm, P = 0.004) and end diastolic left ventricular diameters (47.8 vs. 45.5 mm, P = 0.037) were greater. In stepwise multiple regression, HR variables were the most important factors affecting DBP ratio or the duration of the QT interval. CONCLUSIONS: In conclusion, normotensive diabetic adolescents with impaired nocturnal BP reduction also have impaired autonomic function tests, in association with prolonged QT interval and increased left ventricular diameters. These findings suggest that diabetic adolescents who have the 'non-dipper' phenomenon may need close follow-up for the possible development of vascular complications, such as cardiac arrhythmias and left-ventricular hypertrophy.     

Paroxysmal vagally mediated AV block with recurrent syncope

Paroxysmal complete atrioventricular (AV) block without associated electrocardiographic (ECG) abnormality is not a well recognized entity. A mother and her daughter had recurrent syncopal episodes, but a normal ECG. The episodes were preceded by nausea and vomiting. ECG during these episodes revealed complete heart block. In the mother, one episode was promptly reversed by atropine. Electrophysiological evaluation of the sinus and AV nodal function and atrial and ventricular effective refractory periods before and after autonomic blockade was normal. Provocative manoeuvres failed to induce AV block. Paroxysmal AV block was vagally mediated in one of the patients, as indicated by prompt response to atropine. In the second case, the vagal dependence could not be proved but appears to be the most likely explanation. It thus appears that paroxysmal, vagally mediated complete AV block should be seriously considered in patients with unexplained syncope.     

Severity and multiplicity of microvascular complications are associated with QT interval prolongation in patients with type 2 diabetes

Aims/Introduction

A prolonged QT interval plays a causal role in life‐threatening arrhythmia, and becomes a risk factor for sudden cardiac death. Here, we assessed the association between microvascular complications and the QT interval in patients with type 2 diabetes.

Materials and Methods

Patients with type 2 diabetes (n = 219) admitted to Nippon Medical School Hospital (Tokyo, Japan) for glycemic control were enrolled. QT interval was measured manually in lead II on the electrocardiogram, and corrected for heart rate using Bazett's formula (QTc). Diabetic neuropathy, retinopathy and nephropathy were assessed by neuropathic symptoms or Achilles tendon reflex, ophthalmoscopy and urinary albumin excretion, respectively.

Results

In univariate analyses, female sex (P = 0.025), duration of type 2 diabetes (P = 0.041), body mass index (P = 0.0008), systolic blood pressure (P = 0.0011) and receiving insulin therapy (P < 0.0001) were positively associated with QTc. Patients with each of the three microvascular complications had longer QTc than those without: neuropathy (P = 0.0005), retinopathy (P = 0.0019) and nephropathy (P = 0.0001). As retinopathy or nephropathy progressed, QTc became longer (P < 0.001 and P < 0.001 for trend in retinopathy and nephropathy, respectively). Furthermore, QTc was prolonged with the multiplicity of the microvascular complications (P < 0.001 for trend). Multiple regression analyses showed that neuropathy, nephropathy and the multiplicity of the microvascular complications were independently associated with QTc.

Conclusions

Patients with type 2 diabetes with severe microvascular complications might be at high risk for life‐threatening arrhythmia associated with QT interval prolongation.