The Efficacy and Safety of Ivabradine in Arrhythmias: A Systematic Review

Background: Treating arrhythmia adequately is crucial to prevent cardiac morbidity and mortality. Previous studies report that ivabradine may increase the risk of atrial fibrillation; however, emerging evidence shows that the drug may have beneficial effect in treatment of arrhythmia. Purpose: The present research explored the clinical evidence regarding the clinical efficacy and safety of ivabradine to treat arrhythmias. Method: A comprehensive literature search was conducted using MEDLINE, EMBASE, Scopus, Google Scholar and Web of Science databases. Full text articles that report on the use of ivabradine in human subjects with arrhythmia are included. Studies not written in English language and those not published in the period between 2016 and May 2021 were excluded. Results and discussion: Eight articles were included in the current review after screening a total of 1100 articles. The studies depicted that ivabradine is effective in improving ventricular rate, heart rate, and sinus rhythm in atrial fibrillation and has limited or no side effects. In addition, the findings indicate that combining ivabradine with other medications is more effective for improving the ventricular rate and maintain sinus rhythm than when used alone. Conclusion: Ivabradine alone or in combination with other medications can therefore be used as a potential treatment for arrhythmias. (AU)

24-Hour Holter Monitoring for Identification of an Ideal Ventricular Rate for a Better Quality of Life in Atrial Fibrillation Patients.

Introduction Atrial fibrillation (AF) is the most common persistent cardiac arrhythmia. The impact of AF on quality of life (QoL) is significant, and much has related to the achieved resting ventricular rate (VR). Strategies to control VR can improve QoL in AF patients. However, the ideal VR target remains unclear. Therefore, we aimed to identify the ideal VR target by comparing the QoL of AF patients with different VR cut-off means from the 24-hour Holter (Holter). Methods A cross-sectional study was conducted on AF patients in the international normalized ratio (INR) clinic at Hospital Universiti Sains Malaysia. Patients were fixed with a Holter monitor while QoL was measured using the SF-36v2 Health Survey. Patients were repeatedly divided into mean 24-hour Holter VR above and below 60, 70, 80, 90, and 100 beats per minute (bpm). The differences in the total SF-36v2 score and its components were examined. Results A total of 140 patients completed the study. There was a significant difference in physical role, vitality, mental health, mental component summary, and total SF-36v2 scores for VR above and below 90 bpm. The total SF-36v2 score difference was also significant in the covariate analysis, while other VR cut-offs (60, 70, 80, and 100 bpm) did not show significant changes in total SF-36v2 scores. Conclusion Significant differences were observed in the QoL scores among AF patients, with a cut-off VR of 90 bpm favoring patients with the higher rate. Hence, higher VR is better in terms of QoL among stable AF patients.

Comparison of diltiazem and metoprolol for atrial fibrillation with rapid ventricular rate: Systematic review and meta-analysis.

BACKGROUND: Intravenous calcium channel blockers or beta-blockers are the preferred rate control medications for hemodynamically stable patients with atrial fibrillation with rapid ventricular rate (AF-RVR) in the emergency department. OBJECTIVES: To compare the efficacy of intravenous diltiazem and metoprolol for rate control and safety with respect to development of hypotension and bradycardia in patients with AF-RVR. METHODS: For this systematic review and meta-analysis, we searched PubMed, Embase, Cochrane databases, and the clinicaltrials.gov registry between database inception and 30th May 2021. Articles were included if they compared efficacy and safety of diltiazem versus metoprolol in critically ill adult patients hospitalized with AF-RVR. Outcome measures were achievement of rate control, development of new hypotension, and bradycardia after drug administration. RESULTS: Of 86 records identified, 14 were eligible, all of which had a low to moderate risk of overall bias. The meta-analysis (Mantel-Haenszel, random-effects model) showed that diltiazem use was associated with increased achievement of rate control target compared to metoprolol [14 studies, n = 1732, Odds Ratio (OR): 1.92; 95% Confidence Intervals (CI):1.26 to 2.90; I2 = 61%]. In the pooled analysis, no differences were seen in hypotension using diltiazem vs metoprolol [12 studies, n = 1477, OR: 0.96; 95% CI:0.61 to 1.52; I2 = 35%] or bradycardia [9 studies, n = 1203, OR: 2.44; 95% CI: 0.82 to 7.31; I2 = 48%]. CONCLUSIONS: Intravenous diltiazem is associated with increased achievement of rate control target in patients with AF-RVR compared to metoprolol, while both medications are associated with similar incidence of hypotension and bradycardia.

A case series of very slow atrioventricular nodal reentrant tachycardia resembling junctional tachycardia.

INTRODUCTION: The surface electrocardiography of typical atrioventricular nodal reentrant tachycardia (AVNRT) shows simultaneous ventricular-atrial (RP) activation with pseudo R' in V1 and typical heart rates ranging from 150 to 220/min. Slower rates are suspicious for junctional tachycardia (JT). However, occasionally we encounter typical AVNRT with slow ventricular rates. We describe a series of typical AVNRT cases with heart rates under 110/min. METHODS: A total of 1972 patients with AVNRT who underwent slow pathway ablation were analyzed. Typical AVNRT was diagnosed when; (1) evidence of dual atrioventricular nodal conduction, (2) tachycardia initiation by atrial drive train with atrial-His-atrial response, (3) short septal ventriculoatrial time, and (4) ventricular-atrial-ventricular (V-A-V) response to ventricular overdrive (VOD) pacing with corrected post pacing interval-tachycardia cycle length (cPPI-TCL) > 110 ms. JT was excluded by either termination or advancement of tachycardia by atrial extrastimuli (AES) or atrial overdrive (AOD) pacing. RESULTS: We found 11 patients (age 20-78 years old, six female) who met the above-mentioned criteria. The TCL ranged from 560 to 782 ms. Except for one patient showing tachycardia termination, all patients demonstrated a V-A-V response and cPPI-TCL over 110 ms with VOD. AES or AOD pacing successfully excluded JT by either advancing the tachycardia in 10 patients or by tachycardia termination in one patient. Slow pathway was successfully ablated, and tachycardia was not inducible in all patients. CONCLUSIONS: This case series describes patients with typical AVNRT with slow ventricular rate (less than 110/min) who may mimic JT. We emphasize the importance of using pacing maneuvers to exclude JT.

Angiographic profile and outcomes in persistent non-valvular atrial fibrillation: A study from tertiary care center in North India.

BACKGROUND: The relationship of atrial fibrillation (AF) with coronary artery disease (CAD) is well established, yet it is often missed. There is evidence of myocardial ischemia on stress imaging in AF patients in the absence of obstructive CAD. In this prospective cohort, we studied the angiographic profiles of non-valvular AF patients. METHODS: The study was a nonrandomized, prospective, single-center observational study of consecutive patients of persistent non-valvular AF. Patients symptomatic for AF despite optimal medical therapy for 3 months were recruited and all underwent coronary angiograms (CAG). Patients with prior history of CAD were excluded. RESULTS: A total of 70 patients were followed for a mean duration of 12 ± 1.4 months. The mean age of the study group was 66.07 (±11.49) years. Hypertension was the commonest comorbidity seen in 74% patients. Obstructive CAD was present in 32 (46%) patients, non-obstructive (<50% stenosis) CAD in 17 (24%) patients and normal coronaries in 21 (30%) patients. Overall 49 (70%) patients had evidence of CAD. Amongst patients without obstructive CAD, slow flow was seen in 16 (42%) patients. Lower baseline ejection fraction, lower haemoglobin & albumin levels and higher creatinine levels was associated with increased mortality. In patients without obstructive CAD, hospitalizations for fast ventricular rate were significantly increased in those having slow flow on CAG (p = 0.005). CONCLUSIONS: Majority (70%) of our patients had evidence of atherosclerotic CAD on CAG. A large proportion of patients without obstructive CAD had slow flow on CAG.

Intravenous diltiazem versus metoprolol for atrial fibrillation with rapid ventricular rate: A meta-analysis.

BACKGROUND: Intravenous diltiazem and metoprolol are both commonly used to treat atrial fibrillation (AF) with rapid ventricular rate (RVR) in the emergency department (ED), but the advantages and disadvantages of these drugs cannot be verified. This meta-analysis aimed to assess the efficacy and safety of intravenous diltiazem versus metoprolol for AF with RVR. METHOD: We systematically searched PubMed, Web of Science, Embase, Cochrane library, the China National Knowledge Infrastructure (CNKI), Wanfang, China Biology Medicine disc (CBM) and the WeiPu (VIP). Meta-analysis was performed using weighted mean difference (WMD), relative risk (RR) and 95% confidence interval (CI). Statistical analysis was performed using Review Manager 5.4.1. RESULTS: Seventeen studies involving 1214 patients in nine randomized controlled trials (RCTs) and eight cohort studies were included in meta-analysis, including 643 patients in the intravenous diltiazem group and 571 patients group in the intravenous metoprolol. The results of the meta-analysis showed that compared with intravenous metoprolol, intravenous diltiazem was found higher efficacy (RR =1.11; 95% CI = 1.06 to 1.16, p < 0.00001), shorter average onset time (RR = -1.13; 95% CI = -1.97 to -0.28, p = 0.009), lower ventricular rate (RR = -9.48; 95% CI = -12.13 to -6.82, p<0.00001), less impact on systolic blood pressure (WMD = 3.76; 95% CI: 0.20 to 7.33, P = 0.04), and no significant difference in adverse events (RR = 0.80, 95% CI = 0.55 to 1.14, P = 0.22) and diastolic blood pressure (WMD = -1.20; 95% CI: -3.43 to 1.04, P = 0.29) was found between intravenous diltiazem and metoprolol. CONCLUSION: Intravenous diltiazem has higher efficacy, shorter average onset time, lower ventricular rate, less impact on blood pressure, and with no increase in adverse events compared to intravenous metoprolol.

Evaluation of the blood pressure effects of diltiazem versus metoprolol in the acute treatment of atrial fibrillation with rapid ventricular rate.

PURPOSE: To evaluate the difference in blood pressure effects of diltiazem intravenous push (IVP) and metoprolol IVP in the acute management of atrial fibrillation with rapid ventricular rate (AF with RVR). METHODS: This was a single-center, retrospective cohort study evaluating patients who presented to the emergency department (ED) between January 2012 and September 2018 in AF with RVR and received either diltiazem IVP or metoprolol IVP as the first agent for rate control. The primary objective was the change in systolic blood pressure (SBP) within one hour of initial medication administration. Secondary outcomes included repeat doses within one hour, rate control to <110 beats per minute, and SBP <90 mmHg or decrease by >40% within three hours. Subgroup analysis of patients with a baseline SBP <110 mmHg was conducted. RESULTS: Of the 160 patients included, 80 received diltiazem and 80 metoprolol. The primary outcome of median change in SBP at one hour was a difference of -9 [-21 to 6] mmHg in the diltiazem group versus a difference of -4 [-18 to 9] mmHg in the metoprolol group (p = 0.102). Subgroup analysis (n = 28) of patients with a baseline SBP <110 mmHg demonstrated an increase of 7 [-0.25 to 19] mmHg in the diltiazem group versus increase of 7 [0 to 13] in the metoprolol group (p = 0.910). CONCLUSION: No significant difference was observed in the blood pressure effects of diltiazem IVP versus metoprolol IVP in the acute management of AF with RVR.

Hemodynamic comparison of intravenous push diltiazem versus metoprolol for atrial fibrillation rate control.

OBJECTIVE: Intravenous push (IVP) diltiazem and metoprolol are commonly used for management of atrial fibrillation (AF) with rapid ventricular rate (RVR) in the emergency department (ED). This study's objective was to determine if there was a significant difference in blood pressure reduction between agents. METHODS: This was a single-center, retrospective study of adult patients initially treated with IVP diltiazem or metoprolol in the ED from 2008 to 2018. Primary endpoint was mean reduction in systolic blood pressure (SBP) from baseline to nadir during the study period. Study period was defined as time from first dose of IVP intervention to 30 min after last dose of IVP intervention or first dose of maintenance therapy, whichever came first. RESULTS: A total of 63 diltiazem patients and 45 metoprolol patients met eligibility criteria. Baseline characteristics were similar except for initial ventricular rate (VR) and home beta-blocker use. Median dose of initial intervention was 10 [10-20] mg and 5 [5-5] mg for diltiazem and metoprolol respectively. Mean SBP reduction was 18 ± 22 mmHg for diltiazem compared to 14 ± 15 mmHg for metoprolol (p = .33). Clinically relevant hypotension was similar between groups 14% vs. 16% (p = .86). Rate control was achieved in 35 (56%) of the diltiazem group and 16 (36%) of the metoprolol group (p = .04). CONCLUSION: IVP diltiazem and metoprolol caused similar SBP reduction and hypotension when used for initial management of AF with RVR in the ED. However, rate control was achieved more often with diltiazem.

Reversible bradycardia secondary to myxedema coma: case-report.

Myxedema coma occurs mostly in patients with long-standing untreated or undertreated hypothyroidism. Bradycardia is a well-known cardiac manifestation for myxedema coma; however, not all bradycardia with hypothyroidism are sinus bradycardia. Sick sinus syndrome is a group of arrhythmias caused by the malfunction of the natural pacemaker of the heart. Tachy-Brady syndrome is considered to be a type of sick sinus syndrome, where the heart alternates between tachycardia and bradycardia, and it is usually treated with pacemaker implantation along with rate slowing medical therapy. Here we report a case of an 83-year-old female who presented with myxedema coma and atrial fibrillation with tachycardia and intermittent slow ventricular response. We attempt to review the relationship between these two diseases and conclude that appropriate diagnosis of myxedema coma, may be beneficial in reducing the need for pacemaker implantation.

An atypical complicated left-sided bronchopleural fistula presenting more than seven months after lobectomy.

BACKGROUND: Bronchopleural fistulas (BPF) are abnormal sinus tracts connecting the bronchi and pleural cavity and form after surgical resection of a lung lobe. It is a complication with potentially disastrous sequelae including, failure of the bronchial stump to heal, ischemia of the affected area, and/or infection of the stump. Bronchopleural fistulas caused by surgical intervention most commonly present on the right side and within 7-12 days post-operatively, i.e., subacutely. While the fistula may initially be asymptomatic, they carry a mortality rate of 25-71% in the absence of other comorbidities. CASE PRESENTATION: A 60-year-old female developed a BPF more than seven months after a left lower lobe lung lobectomy for non-small cell adenocarcinoma is presented. She was seen at our hospital on multiple occasions after her lobectomy with no evidence of a developing fistula on chest computer tomography (CT) during those visits. During her most recent presentation, roughly 7 months postoperatively, she was noted on imaging to have a new left-sided bronchopleural fistula. Bronchoscopy with lavage and culture of the fistula grew Pseudomonas Aeruginosa, for which she received appropriate treatment. Further surgical interventions were deferred due to poor prognosis. Her presentation differed from the typical BPF presentation in that it was left-sided and occurred out of the window of its usual occurrence. CONCLUSION: Late-onset BPF is an important diagnosis to consider in patients who have undergone lung resection, regardless of the type of surgery or postoperative duration, especially when patients are known to have multiple predisposing factors.

Are implantable cardiac monitors reliable tools for cardiac arrhythmias detection? An intra-patient comparison with permanent pacemakers.

INTRODUCTION: Implantable cardiac monitor (ICM) is an established tool for the management of unexplained syncope and atrial fibrillation (AF) even if its accuracy of arrhythmia detection may be suboptimal. The aim of this study was to perform an intra-patient comparison of the diagnostic capability of ICM with a dual-chamber PM as a gold standard. METHODS: We included 19 patients with a previously implanted ICM (BioMonitor 2 Biotronik, Berlin, Germany), who received a dual-chamber PM for standard indications. ICM-detected arrhythmic events in a 6-month follow-up were compared with those detected by the PM and classified by visual inspection of intracardiac electrograms. RESULTS: During follow up, ICMs generated 15 false asystole and 39 false bradycardia detections in 5 patients (26.3%) due to recurrent premature ventricular contractions. A total of 34 true high ventricular rate (HVR) episodes were detected by the PM. Of them, 30 (88%) events were also recorded by the ICM, which further detected 14 false HVR snapshots, leading to a sensitivity and positive predictive value of 88% and 68%, respectively. In addition, PM identified 234 true AF episodes. Of them, 225 (96%) events were also detected by the ICM, while 8 (42%) ICMs stored 50 AF episodes classified as false positives. The ICM sensitivity for AF was 96% with a positive predictive value of 82%. CONCLUSION: Our intra-patient comparison with permanent PM confirmed that ICM is an effective tool for cardiac arrhythmias detection. ICM algorithms for AF and HVR detection were highly sensitive with an acceptable rate of false positive episodes.

A Rare Case of Spontaneous Isolated Dissection of the Superior Mesenteric Artery.

Isolated spontaneous dissection of the superior mesenteric artery (SMA) is a rare entity that is increasingly becoming recognized due to an improvement in imaging techniques. The pathogenesis of a spontaneous SMA dissection has yet to be fully elucidated. Here, we present the case of isolated SMA dissection in a 65-year-old female who was seen in the emergency room with acute substernal chest and left upper quadrant abdominal pain. She was managed for atrial fibrillation with a rapid ventricular response. She underwent computed tomography (CT) angiogram of the chest, abdomen, and pelvis, which revealed focal dissection involving SMA measuring 2.7 cm in width. Vascular surgery recommended conservative management with low-dose daily aspirin and the optimization of blood pressure control. She subsequently was seen as an outpatient with complete resolution of abdominal pain. Given the low incidence rate, vascular surgery evaluation may be required to determine the best course of management. Treatment needs to be individualized for each patient. Since abdominal pain is a common complaint for which patients are seen in each clinical setting, it is important to highlight this case to create awareness regarding the possibility of isolated SMA dissection as one of the underlying etiologies.

Effects of selectively resecting the lower half of stellate ganglion on fast ventricular rate in canines with persistent atrial fibrillation / 中国胸心血管外科临床杂志

@#Objective To determine the effects of resecting the lower half of left stellate ganglion (LSG) on fast ventricular rate (VR) in persistent atrial fibrillation (AF) and its mechanism. Methods Twelve mature healthy male beagle dogs (15–25 kg) were studied. They were randomly divided into two groups (an experimental group and a control group, 6 dogs in each group). The control group were merely performed with rapid left atrial pacing to induce persistent AF. The experimental group were disposed with rapid left atrial pacing and received resection of the lower half of LSG after the persistent AF was documented. Simultaneously the ventricular rates were monitored separately before anesthesia, after anesthesia, 30 minutes and one month after LSG resection. The forward passing effective refractory period (ERP) of the canine atrioventricular node (AVN) was also measured. Results Each dog was documented with persistent AF after 3–6 weeks’ left atrial pacing. After resecting the lower half of LSG for 30 minutes (the control group was only observed for 30 minutes without LSG resection), the average VR of the control group attained 144.5±4.2 beats/min, while that of the experimental group was 121.5±8.7 beats/min (P<0.001). After resecting the lower half of LSG for one month (the control group was observed for one month without LSG resection), the average VR of the control group was 139.2±5.6 beats/min, while that of the experimental group was 106.5±4.9 beats/min (P<0.001). Meantime, the forward passing ERP of AVN of the experimental group was significantly prolonged than that of the control group (265.6±7.8 msvs.251.1±4.6 ms, P=0.003). Conclusion Resection of the lower half of LSG is efficient in reducing VR in canines with persistent AF, one of the mechanisms of which may be prolonging the forward passing ERP of AVN.

Retrospective Evaluation of the Effect of Heart Rate on Survival in Dogs with Atrial Fibrillation.

BACKGROUND: Atrial fibrillation (AF) usually is associated with a rapid ventricular rate. The optimal heart rate (HR) during AF is unknown. HYPOTHESIS/OBJECTIVES: Heart rate affects survival in dogs with chronic AF. ANIMALS: Forty-six dogs with AF and 24-hour ambulatory recordings were evaluated. METHODS: Retrospective study. Holter-derived HR variables were analyzed as follows: mean HR (meanHR, 24-hour average), minimum HR (minHR, 1-minute average), maximum HR (maxHR, 1-minute average). Survival times were recorded from the time of presumed adequate rate control. The primary endpoint was all-cause mortality. Cox proportional hazards analysis identified variables independently associated with survival; Kaplan-Meier survival analysis estimated the median survival time of dogs with meanHR <125 bpm versus ≥125 bpm. RESULTS: All 46 dogs had structural heart disease; 31 of 46 had congestive heart failure (CHF), 44 of 46 received antiarrhythmic drugs. Of 15 dogs with cardiac death, 14 had CHF. Median time to all-cause death was 524 days (Interquartile range (IQR), 76-1,037 days). MeanHR was 125 bpm (range, 62-203 bpm), minHR was 82 bpm (range, 37-163 bpm), maxHR was 217 bpm (range, 126-307 bpm). These were significantly correlated with all-cause and cardiac-related mortality. For every 10 bpm increase in meanHR, the risk of all-cause mortality increased by 35% (hazard ratio, 1.35; 95% CI, 1.17-1.55; P < 0.001). Median survival time of dogs with meanHR<125 bpm (n = 23) was significantly longer (1,037 days; range, 524-open) than meanHR ≥125 bpm (n = 23; 105 days; range, 67-267 days; P = 0.0012). Mean HR was independently associated with all-cause and cardiovascular mortality (P < 0.003). CONCLUSIONS AND CLINICAL IMPORTANCE: Holter-derived meanHR affects survival in dogs with AF. Dogs with meanHR <125 bpm lived longer than those with meanHR ≥ 125 bpm.

Simulation of ventricular rate control during atrial fibrillation using ionic channel blockers.

BACKGROUND: The atrioventricular (AV) node is the only compartment that conducts an electrical impulse between the atria and the ventricles. The main role of the AV node is to facilitate efficient pumping by conducting excitation slowly between the two chambers as well as reduce the ventricular rate during atrial fibrillation (AF). METHODS: Using computer simulations, we investigated excitation conduction from the right atrium to the bundle of His during high-rate atrial excitation with or without partial blocking of the calcium or potassium ionic current. RESULTS: Our simulations revealed differences in rate reduction and repolarization effects between calcium and potassium current blocking and high degree of potassium current blocking required to reduce the ventricular rate during AF. CONCLUSIONS: Our simulation results explain why potassium current blockers are not recommended for controlling ventricular rate during AF.

Ventricular rate stabilization for treatment of recurrent VT.

A patient with ischaemic cardiomyopathy received a secondary prevention VVI implantable cardioverter-defibrillator (ICD) after an episode of sustained ventricular tachycardia (VT). Because of recurrent VTs transmitted via CareLink, medical therapy was optimized and VT ablation was performed. Subsequently, a fast VT with a typical short-long-short initiation developed. In addition, there was an increasing need for ventricular pacing due to sinus bradycardia. This new type of VT could be successfully dealt with by upgrading to DDD ICD and activating the Ventricular Rate Stabilization algorithm.

Successful treatment of ventricular fibrillation storm triggered by short-long-short sequence; time to avoid managed ventricular pacing.

Sudden cardiac death (SCD) in hypertrophic cardiomyopathy (HCM) is caused by ventricular tachyarrhythmia that can be effectively treated by implantable cardioverter defibrillator (ICD) therapy. We report of a 28-year-old man with HCM and a dual chamber ICD, originally implanted for primary prevention of SCD, (programmed to AAI(R)-DDD(R); managed ventricular pacing (MVP) mode, Medtronic Inc. St Paul, MN USA). He presented with recurrent ICD shocks due to ventricular fibrillation (VF) despite antiarrhythmic therapy. Careful assessment of the stored electrograms demonstrated a repetitive pattern of VF initiation following short-long-short sequences. Initially, activation of ventricular rate stabilization (VRS) algorithm failed to prevent recurrent VF. Ultimately, deactivation of MVP and reprogramming the device to DDD mode with VRS on, resulted in arrhythmia suppression and avoidance of ICD shocks. Physicians should be aware that although VRS function is available in MVP mode, it does not function in the AAI mode during MVP; in order to effectively treat short-long-short sequence induced ventricular arrhythmia by device programming.

Effects of amiodarone combined with succinylmetroprolol sustained-release tablets on cardiac function in patients with atrial fibrillation and congestive heart failure / 中国生化药物杂志

Objective To investigate the clinical efficacy of amiodarone combined with succinylmetroprolol sustained-release tablets in patients with atrial fibrillation and congestive heart failure (CHF) complicated with atrial fibrillation (AF), and to observe the effect of amiodarone on heart function and ventricular rate.MethodsIn people's hospital of Anji county from June 2013 to June 2016 a total of 80 patients with atrial fibrillation and heart failure were enrolled in this study.The patients were randomly divided into control group and treatment group, 40 cases.(Ventricular rate, resting ventricular rate), cardiac function (ejection fraction-EF, stroke volume-SV, cardiac output-CO and left ventricular function) were measured before treatment and 6 months after treatment Ventricular end-diastolic early/late peak velocity ratio-VA/VE).The clinical efficacy and side effects during the treatment were statistically analyzed.ResultsThe ventricular rate and resting ventricular rate after exercise were significantly lower than those before treatment, but the ventricular rate and resting ventricular rate were significantly lower in the treatment group than those in the control group after 6 months of treatment (P<0.05).The VA/VE was significantly lower than that of the control group at 6 months after treatment, and the values of EF, SV and CO were significantly higher than those of the control group at 6 months after the treatment, SV, CO were significantly higher than the control group(P<0.05).Treatment group, the total effective rate was 92.5%, significantly higher than the control group 72.5%(χ2=7.77, P=0.02).No significant adverse reactions during treatment.ConclusionRapid ventricular rate of atrial fibrillation with congestive heart failure were treated with amiodarone combined with metoprolol succinate sustained release tablets can conducive to the ventricular rate and heart function of patients, and the effect is remarkable, safe, so it can be recommended as the drug of choice for clinical treatment of patients.

Electrocardiographic Parameters Indicating Worse Evolution in Patients with Acquired Long QT Syndrome and Torsades de Pointes.

BACKGROUND: Acquired long QT syndrome (a-LQTS) is associated with life-threatening ventricular arrhythmias, mainly torsades de pointes (TdP). ECG parameters predicting evolving into ventricular fibrillation (VF) are ill defined. AIMS: To determine ECG parameters preceding and during TdP associated with higher risk of developing VF. METHODS: We analyzed 151 episodes of TdP, recorded in 28 patients with a-LQTS (mean QTc 638 ms ± 57). RESULTS: All 28 patients had prolonged QT interval, (mean QTc 638 ms ± 57) ranging from 502 ms to 858 ms correcting by Bazett's formula. The mean TdP heart rate was 218 bpm ± 38 (mean cycle length of TdP 274 ± 47 ms). We classified TdPs episodes into "slower"-TdP (s-TdP) < 220 bpm (range from 145-220 bpm) observed in 81 (53.6%) episodes and "faster"-TdP (f-TdP) ≥ 220 bpm (ranged from 221-281 bpm) observed in 70 (46.4%) episodes. Among 151 episodes of TdP, 21 (13.9%) were unstable (converted into VF). Out of 81 episodes of "slower"-TdP only 2 (2.5%) episodes converted into VF. The mean coupling interval (CI) of the PVC initiating TdP was 510 ms ± 118, the pause-RR interval was 1147 ms ± 335, the prematurity index (PI) of PVC that initiated TdP was 0.45 ± 0.13. The mean cycle length variability of TdP (VRV-TdP) was 30.79 ms ± 19.7. U wave was observed in 86 episodes (56.9%), among that in 69 episodes, the U/T wave ratio was > 1. Macro T wave alternans was observed in 4 patients. The QT interval was not different in patients with VF(+) and VF(-) episodes, 633 ± 60 and 639 ± 57, respectively. CONCLUSIONS: Some electrocardiographic parameters can be helpful in determining the risk of TdP evolving into VF. The slower ventricular rate (< 220 bpm), the higher rate instability (VRV > 30 ms) and the short episodes < 20 beats could predict benign evolution.