Evaluation of short and mid-term clinical outcomes in patients with aortic coarctation treated with self-expandable stents.

The present study aimed to evaluate the outcomes of percutaneous treatment of aortic coarctation using self-expandable uncovered Nitinol stents. We conducted a retrospective clinical data review of all patients with aortic coarctation and treated with self-expandable uncovered Nitinol stents at our institution between 2009 and 2019. The gradient pressure across the coarctation site was measured using aortography. Follow-up echocardiography and computed tomography angiography were performed to assess possible stent complications. A total of 127 stents were successfully implanted in 125 patients (64.8% males) with a mean age of 35.36 ± 11.9 years. The gradient across the coarctation site decreased significantly from 67.48 ± 14.79 to 5.04 ± 3.01 mmHg (P < 0.001) after self-expandable stent implantation. Systolic blood pressure (SBP) decreased significantly from 175.53 ± 15.99 to 147.22 ± 12.83 mmHg (P < 0.001) after self-expandable stenting. There were no major technical or clinical complications, including balloon rupture, aneurysmal formation, infection, secondary stent migration, thrombosis, death during the procedure, and in-hospital mortality. On a mean follow-up of 48 ± 23.6 months (12-120 months), the gradient [from 59.43 ± 15.42 to 3.72 ± 1.38 mmHg (P < 0.001)] and SBP [from 175.53 ± 15.99 to 127.99 ± 7.82 mmHg (P < 0.001)] decreased significantly. There was no mortality, aneurysmal formation in the stent site, dislocation, or aortic re-stenosis requiring intervention during mid-term follow-up. Treatment of aortic coarctation using a self-expandable uncovered nitinol stent is safe and effective with promising mid-term outcomes.

Genetic Determinants of Response to Statins in Cardiovascular Diseases.

Despite extensive efforts to identify patients with cardiovascular disease (CVD) who could most benefit from the treatment approach, patients vary in their benefit from therapy and propensity for adverse drug events. Genetic variability in individual responses to drugs (pharmacogenetics) is considered an essential determinant in responding to a drug. Thus, understanding these pharmacogenomic relationships has led to a substantial focus on mechanisms of disease and drug response. In turn, understanding the genomic and molecular bases of variables that might be involved in drug response is the main step in personalized medicine. There is a growing body of data evaluating drug-gene interactions in recent years, some of which have led to FDA recommendations and detection of markers to predict drug responses (e.g., genetic variant in VKORC1 and CYP2C9 genes for prediction of drug response in warfarin treatment). Also, statins are widely prescribed drugs for the prevention of CVD. Atorvastatin, fluvastatin, rosuvastatin, simvastatin, and lovastatin are the most common statins used to manage dyslipidemia. This review provides an overview of the current knowledge on the pharmacogenetics of statins, which are being used to treat cardiovascular diseases.

Evaluation of the effects of isoproterenol on arrhythmia recurrence following catheter ablation in patients with atrioventricular nodal re-entrant tachycardia: A randomized controlled clinical trial.

We aimed to determine the effects of isoproterenol on arrhythmia recurrence in atrioventricular nodal re-entrant tachycardia (AVNRT) patients treated with catheter ablation. The present randomized controlled clinical trial was conducted on AVNRT patients candidates for radiofrequency ablation (RFA). The patients were randomly assigned to receive isoproterenol (0.5-4 µg/min) or not (control group) for arrhythmia re-induction after ablation. The results of the electrophysiological (EP) study, the ablation parameters, and the arrhythmia recurrence rate were recorded. We evaluated 206 patients (53 males and 153 females) with a mean (SD) age of 49.87 (15.5) years in two groups of isoproterenol (n = 103) and control (n = 103). No statistically significant difference was observed between the two studied groups in age, gender, EP study, and ablation parameters. The success rate of ablation was 100% in both groups. During ~16.5 months of follow-up, one patient (1%) in the isoproterenol group and four patients (3.8%) in the control group experienced AVNRT recurrence (HR = 0.245; 95% confidence interval [CI], 0.043-1.418; p = .173). Based on the Kaplan-Meier analysis, there was no significant difference in the incidence rate of arrhythmia recurrence during the follow-up period between the two studied groups (p = .129). Additionally, there were no significant differences between the arrhythmia's recurrence according to age, gender, junctional rhythm, type of AVNRT arrhythmia, and DAVN persistence after ablation. Although isoproterenol administration for arrhythmia re-induction after ablation did not alleviate the treatment outcomes and arrhythmia recurrence following RFA in AVNRT patients, further studies with a larger sample size and a longer duration of follow-up are necessary.

Increasing cardiac troponin-I level as a cardiac injury index correlates with in-hospital mortality and biofactors in severe hospitalised COVID-19 patients.

BACKGROUND: Severe acute respiratory syndrome coronavirus-2 raised in 2019 (COVID-19) affects the lung tissue and other organs, specifically the heart. METHODS: The current study evaluated 120 hospitalised patients with severe COVID-19 between March 2021 and February 2022. Patients' demographics, vital signs, electrocardiogram abnormalities, clinical laboratory tests, including troponin I (TPI), mortality, and discharge type, were recorded. RESULTS: Among the 120 hospitalised patients with severe COVID-19, 54 (45.0%) patients were male, with an average age of 63.2 ± 1.4. Many patients have chronic comorbidities, including hypertension (51.6%), diabetes mellitus (34.1%), and ischemic heart disease (17.5%). The in-hospital and six months after the discharge mortality were 45.8% and 21.5%, respectively. Cardiac injury was observed in 14 (11.7%) patients with a mean TPI level of 8.386 ± 17.89 µg/L, and patients with cardiac injury had higher mortality than those without cardiac injury (P < 0.001). Furthermore, the cardiac injury was meaningfully correlated with age (ρ = 0.182, P = 0.019), history of ischemic heart disease (ρ = 0.176, P = 0.05), hospitalisation result and mortality (ρ = 0.261, P = 0.004), inpatient in ICU (ρ = 0.219, P = 0.016), and serum levels of urea (ρ = 0.244, P = 0.008) and creatinine (ρ = 0.197, P = 0.033). Additionally, the discharge results were significantly correlated with oxygen saturation with (ρ = -0.23, P = 0.02) and without (ρ = -0.3, P = 0.001) oxygen therapy, D-dimer (ρ = 0.328, P = 0.019), LDH (ρ = 0.308, P = 0.003), urea (ρ = 0.2, P = 0.03), and creatinine (ρ = 0.17, P = 0.06) levels. CONCLUSION: Elevated TPI levels are associated with increased mortality in severe COVID-19 patients. Therefore, TPI may be a beneficial biofactor for early diagnosis of cardiac injury and preventing a high mortality rate.

Evaluation of the effect of crocin on prevention of atrial fibrillation after coronary artery bypass grafting or heart valve replacement: A double-blind, randomized, placebo-controlled trial.

Objective: The aim of this study was to evaluate the effect of crocin on the prevention of atrial fibrillation after coronary artery bypass grafting (CABG) and heart valve replacement. Materials and Methods: 100 patients who were scheduled for CABG or heart valve replacement surgeries were randomly assigned into two groups of treatment and placebo. In the treatment group, patients received crocin tablets from three days prior to surgery and on the first three postoperative days (for a total of six days). During the first three days after surgery, postoperative atrial fibrillation (POAF) was assessed by electrocardiogram monitoring. Prooxidant-antioxidant balance (PAB) and c-reactive protein (CRP) levels were also assessed. Results: POAF developed in 7 patients in the treatment group versus 18 patients in the control (p=0.02). PAB levels were significantly lower in the crocin group (p<0.001), while differences in CRP levels were insignificant (p=0.39). Conclusion: It seems that prophylactic use of crocin is effective in reducing the incidence of POAF in patients undergoing heart surgeries.

An incidental finding of unroofed coronary sinus during angiography confirmed by 3D echocardiography; A case report.

Unroofed coronary sinus (UCS) is an uncommon congenital heart anomaly and the most unusual type of atrial septal defect. This report presents a 71-year-old female with palpitation and dyspnea following an emotional stress, who was referred for ablation of typical atrial flutter. Finally diagnosed with a partially unroofed CS causing a bidirectional shunt.

Atretic Coronary Sinus Orifice and a Diverticulum of Coronary Sinus Associated with Persistent Left Superior Vena Cava and Accessory Pathway.

Coronary orifice atresia and diverticula are considered rare congenital conditions. Our understanding of the coronary sinus (CS) and venous drainage anatomy plays a crucial role in performing interventions and surgical procedures required to improve treatment options and related prognosis for these patients. The case study described herein involves a 29-year-old female patient who was diagnosed with coronary orifice atresia and diverticula. The patient's electrocardiography revealed normal sinus rhythm, short PR interval, and delta wave. Transthoracic echocardiography results showed the subject also suffered from mild CS dilation associated with coronary orifice atresia and diverticula. Our clinical intervention included the use of agitated saline injection which was administered intravenously into the patient's left arm. Our clinical observations during the administration of agitated saline solution did not indicate the presence of any detectable air bubbles entering into the CS. The results of two-dimensional and color flow Doppler study showed that CS connection to the right atrium appeared to be atretic. During our examination, we were also successful in detecting a pulsatile free echo space which was connected through an isthmus to the CS. Electrophysiology study and coronary angiogram performed on the subject confirmed our clinical diagnosis and findings of CS atresia, diverticula, and left superior vena cava.

Predictors of worsening TR severity after right ventricular lead placement: any added value by post-procedural fluoroscopy versus three -dimensional echocardiography?

BACKGROUND: The effect of right ventricular (RV) leads on tricuspid valve has been already raised concerns, especially in terms of prognostic implication. For such assessment, three-dimensional transthoracic echocardiography (3D-TTE) has been used previously but there was no data on the use of post-procedural fluoroscopy in the literature. METHODS: We prospectively enrolled 59 patients who underwent clinically indicated placement of pacemaker or implantable cardioverter defibrillator (ICD). Vena contracta (VC) and tricuspid regurgitation (TR) severity were measured using two-dimensional transthoracic echocardiography (2D-TTE) at baseline. Follow up 3D-TTE was performed 6 months after device implantation to assess TR severity and RV lead location. RESULTS: Lead placement position in TV was defined in 51 cases.TR VC was increased after the lead placement, compared to the baseline study (VC: 3.86 ± 2.32 vs 3.18 ± 2.39; p = 0.005), with one grade worsening in TR in 25.4% of cases. The mean changes in VC levels were 1.14 ± 0.67 mm. Among all investigated parameters, VC changes were predicted based on lead placement position only in 3D-TTE (p < 0.001) while the other variables including fluoroscopy parameters were not informative. CONCLUSION: The RV Lead location examined by 3D-TTE seems to be a valuable parameter to predict the changes in the severity of the tricuspid regurgitation. Fluoroscopy findings did not improve the predictive performance, at least in short term follow up.

Prevalence of ABO and Rh blood groups and their association with demographic and anthropometric factors in an Iranian population: Mashad study.

BACKGROUND: Blood groups appear to be markers for various human diseases and their distribution among different communities, ethnic groups and geographical boundaries varies over time. AIMS: We aimed to investigate the frequency of ABO and Rh blood groups and their relationship with demographic and anthropometric characteristics among Iranian residents in Mashad. METHODS: ABO and Rh blood groups were determined among 7268 participants from the MASHAD cohort study and their relationships with demographic and anthropometric parameters were evaluated. This part of the study was done in January 2017. Student t-test, ANOVA, Bonferroni' and Chi-squared were used for comparison of quantitative and qualitative variables. RESULTS: The most common blood group was O (33.8%); AB was the least common (8.3%). The prevalence of Rh-positive and Rh-negative was 88.2% and 11.8% respectively. There were statistically significant associations between ABO blood groups and demi-span (P = 0.03), even after correction for multiple comparisons. CONCLUSION: Our findings showed there was no relationship between ABO blood groups and demographic characteristics although there was an association with anthropometric measurements such as demi-span.

Ocular Manifestations of Hospitalized Patients with COVID-19 in Northeast of Iran.

PURPOSE: To evaluate ocular findings in patients with Coronavirus Disease 2019 (COVID-19) in the Northeast of Iran. METHODS: In a cross-sectional, observational study all consecutive patients with confirmed COVID-19 diagnosis at the central referral center of these patients in northeast of Iran were included. Ocular examinations (external and slit) were randomly performed for the patients who were admitted to the Intensive Care Unit (ICU) and six COVID wards of the hospital. Moreover, Chart records and serum chemistry results were collected. RESULTS: A total of 142 patients with the mean age of 62.6 ± 15 years (range: 23-96 years) and almost equal gender distribution (male: N = 77, 54.2%) were included in the study. During the initial external examination by the ophthalmologist, 44 (31%) patients were found to have conjunctival hyperemia and 22 (15.5%) patients had chemosis. Consecutive slit examination showed 41 (28.9%) conjunctival hyperemia, 22 (15.5%) chemosis, 11 (7.7%) cataract, and 9 (6.3%) diabetic retinopathy. The patients with at least one ocular manifestation had significantly higher blood urea levels at the time of admission compared to those with no obvious ocular involvement (median: 41.5, IQR: 28-66.3 vs. median: 33, IQR: 23.8-51.8, P = .023). Moreover, a significant difference was observed in the total white blood cell count, lymphocyte percent, neutrophil count, Erythrocyte Sedimentation Rate (ESR), and blood urea level between patients with positive and negative Polymerase Chain Reaction (PCR) for SARS-CoV-2 virus. None of the patients reported ocular symptoms prior to systemic involvement. The proportion of patients with at least one ocular manifestation was significantly higher in those admitted in the ICU compared to the non-ICU wards. wards. While conjunctival hyperemia was the most prevalent ocular finding in all patients, chemosis was the most common ocular manifestation in ICU admitted patients. CONCLUSION: Ocular manifestation was observed in more than half of our COVID-19 patients. Hence, it seems important to involve ophthalmologist in the diagnosis and management of these patients.

Investigating the Manifestation of Coronary Artery Disease and Determining the Role of Effective Factors in the Need for Pacemaker Insertion in These Patients.

BACKGROUND: Many patients who are candidates for a pacemaker are also at the same time risk factors for coronary artery disease such as high blood pressure, hypertension, diabetes, and hyperlipidemia, and therefore the probability of having coronary artery disease is significant. Effective diagnostic measures can be taken to prove the factors affecting the incidence of CAD in patients undergoing pacemakers at high-risk, including angiography. Therefore, it can prevent complications during and after pacemaker implantation, which leads to an increase in the quality of treatment in patients requiring pacemaker implantation. AIM: Therefore, the purpose of this study was to determine the predictive factors of significant coronary artery disease in patients with pacemaker implantation to identify patients in need of coronary angiography at the time of pacemaker implantation. METHODS: This retrospective study was carried out to examine the patients' files that were placed at the heart of Imam Reza Hospital during the period between March 2017 and September 2017. Demographic data, risk factors, echocardiography findings, and angiography, were collected and then recorded using a checklist. Statistical analysis was performed using SPSS software version 22 and Chi-square, and Mann-Whitney tests were used for determining significates variables. RESULTS: A group of 102 patients who had undergone a permanent cardiac pacemaker insertion due to an atrioventricular (AV) Block were included in the study, and also coronary anatomy was determined coronary angiography. Based on the results, 13.7% of patients with cardiac pacemaker had obstructive coronary artery disease (stenosis > 70%). Factors affecting coronary artery stenosis on angiography include gender, chest pain, history of myocardial infarction, angioplasty, diabetes, smoking, history of aspirin intake, calcium blocker and Plavix, high hematocrit, ST elevation and ST depression in the ECG, and severe mitral regurgitation. CONCLUSION: It seems that in most patients requiring permanent pacemaker insertion because of the atrioventricular (AV) Block, angiography does not change the patient's fate, and so can be ignored. However, in patients who have several risk factors from the listed above, coronary angiography is recommended during admission.

Morphine Post-Conditioning Effect on QT Dispersion in Patients Undergoing Primary Percutaneous Coronary Intervention on Anterior Descending Cardiac Artery: A Cohort Study.

INTRODUCTION: QT dispersion is the difference between the maximum and minimum QTc interval in a 12-lead electrocardiogram (ECG). Some researchers have demonstrated the effects of an increase of QT-d in STEMI and its reduction with successful therapy. The aim of this study was to investigate the morphine post-conditioning effect on the QT dispersion in patients undergoing primary percutaneous coronary intervention (PCI) on anterior descending cardiac artery. METHODS: This cohort study was conducted on STEMI patients admitted to the Hospital of Imam Reza (AS), Mashhad, Iran, from March 2015 to February 2016 who were undergoing primary angioplasty on the anterior descending cardiac artery. The patients were divided into two groups based on the intake or non-intake of morphine (5 mg morphine for the period of 30 minutes prior to PCI). Parameters, including age, gender, history of diabetes, and blood pressure as well as admission and 24 hours after PCI ejection fraction (EF) and QT-d, were recorded in all patients and compared between the two intervention and control groups. Independent and paired t-tests and chi-square test were used to compare the qualitative and quantitative data between the two groups using SPSS version 19 software. RESULTS: The present research was performed on 77 patients (61 males) with mean age of 58.71±11.84 years in the two groups of morphine consumption before PCI (n=46) and control (n=31). No statistical difference was found among the groups in age, gender, diabetes, hypertension, and onset of symptoms until primary PCI. Admission electrocardiogram QT-d value in the positive exposure group showed no significant difference with the control group, but QT-d value at 24 hours after PCI was lower in the positive exposure group than in the control group (morphine versus control: 40.32±6.98 versus 59.64±8.89; p=0.000). QT-d value 24 hours after PCI compared with the admission QT-d value was significantly reduced in both groups. The mean decrease of admission QT-d relative to QT-d 24 hours after PCI was higher in the positive exposure group than in the control group, and this difference was also statistically significant (morphine versus control: 48.65±9.95 versus 25.74±6.66; p=0.000). CONCLUSION: The findings of the current survey demonstrated that morphine consumption before PCI can further reduce QT-d value in an electrocardiogram for PCI as compared to patients who did not take morphine before PCI.

Diagnostic value of fragmented QRS complex in myocardial scar detection: systematic review and meta-analysis of the literature.

BACKGROUND AND AIM: The present study aimed to investigate the diagnostic value of fragmented QRS complex (fQRS) on 12-lead electrocardiogram (ECG) for myocardial scar detection, and presented the results in a systematic review and meta-analysis format. METHODS: Medline, SCOPUS, and ISI Web of Knowledge were searched electronically with "Fragmented QRS" or "fQRS" as key words. All related studies that had evaluated the accuracy of fQRS for myocardial scar diagnosis were included. RESULTS: Eight studies (2560 patients) were finally included in the systematic review. Specificity assessment could be evaluated only by five out of these eight articles. Overall pooled sensitivity of fQRS, Q wave, and mixed Q-fQRS was 68% (65-71), 51% (47-55), and 74% (69-79) and the pooled specificity was 80% (79-81), 97% (97-98) and 92% (91-93), respectively. CONCLUSIONS: Fragmented QRS is a novel ECG marker with more sensitivity and less specificity than Q wave. A combination of fQRS with Q wave in a 12-lead ECG results in up to 74% sensitivity and 92% specificity. Additional studies are needed to assess the significance of this ECG parameter for regional myocardial scar detection.

Comparison between fragmented QRS and Q waves in myocardial scar detection using myocardial perfusion single photon emission computed tomography.

BACKGROUND: Accurate diagnosis of myocardial infarction (MI) is of paramount importance in patient management, which necessitates the development of efficient and accurate diagnostic methods. Q wave is not present in all patients with MI, and its prevalence is declining. Recently, fragmented QRS (fQRS) complex has been introduced as a marker of prior MI. AIM: To investigate diagnostic value of fQRS compared to Q wave. METHODS: We included 500 consecutive patients with known or suspected coronary artery disease who underwent two days of gated myocardial perfusion imaging using dipyridamole pharmacologic stress. Electrocardiogram (ECG) was evaluated to detect fQRS as well as Q-wave. Finally, subjects were compared in terms of ventricular perfusion and function indices. RESULTS: A total of 207 men and 269 women with mean age of 57.06 ± 12 years were studied. ECG analysis showed that 14.3% of the patients had both fQRS and Q waves, 30.7% had fQRS, and 3.8% had Q waves. Fixed myocardial perfusion defect was noted in 22.3% of patients according to MPIs. Sensitivity, specificity, and positive and negative predictive values for myocardial scar detection were 78%, 65%, 39%, and 91%, respectively, for fQRS and 61%, 94%, 76%, and 89%, respectively, for Q wave. CONCLUSIONS: Although fQRS had lower specificity compared to Q wave in the detection of myocardial scar, due to higher sensitivity and negative predictive value can be an invaluable diagnostic index. There is also an incremental value for fQRS in association with Q-wave in myocardial scar assessment.

Role of isoproterenol in predicting the success of catheter ablation in patients with reproducibly inducible atrioventricular nodal reentrant tachycardia.

Noninducibility of the arrhythmia is the widely accepted endpoint of successful ablation of atrioventricular nodal reentrant tachycardia (AVNRT). However, to rely upon that as the only endpoint, the arrhythmia must also be inducible before ablation. Despite the fact that AVNRT is not reproducibly inducible in a significant number of cases, the role of reproducible arrhythmia induction and its relationship with the infusion of isoproterenol after successful ablation of AVNRT has not been well defined. We studied 175 consecutive patients who all underwent successful radiofrequency ablation after showing that they had reproducibly inducible AVNRT without use of isoproterenol. In Group 1 (n=90), isoproterenol was used for arrhythmia reinduction after ablation, whereas in Group 2 (n=85) it was not. The procedural and follow-up data of both groups were recorded, and the results of appropriate statistical tests were analyzed. During a mean follow-up time of 18.7 ± 4.5 months, 4 patients in Group 1 and 3 patients in Group 2 experienced recurrences. Regardless of elimination or modification of slow-pathway conduction, no significant difference was seen in the recurrence rates of AVNRT between the 2 groups (P=0.72). We conclude that, when the original arrhythmia in patients with AVNRT is reproducibly inducible in the basal state, the use of isoproterenol after ablation in order to confirm the noninducibility of AVNRT does not appear to alter the recurrence rates and can be omitted.

Outcome of ventricular tachycardia ablation in patients with nonischemic cardiomyopathy: the impact of noninducibility.

BACKGROUND: Ablation failure and recurrence rates after ventricular tachycardia (VT) ablation in nonischemic cardiomyopathy are high and the optimal procedural end point is not well defined. This study assessed the outcome after ablation, the impact of noninducibility, and other potential predictors of VT recurrence. METHODS AND RESULTS: Forty-five patients with nonischemic cardiomyopathy (60±16 years; left ventricular ejection fraction, 44±14%) accepted for VT ablation were included. Epicardial mapping was performed in 29 (64%). A median of 2 (first-to-third quartile, 2-4) VTs (cycle length, 342±77 ms) were induced per patient. After ablation, the complete programmed electric stimulation protocol (3 drive cycle length, 3 extrastimuli ≥200 ms, and burst≥2 sites) was repeated. Complete success (noninducibility of any monomorphic VT) was achieved in 17 patients (38%), partial success (elimination of clinical VT, persistent inducibility of nonclinical VT) in 17 patients (38%), and failure (persistent inducibility of clinical VT) in 11 patients (24%). During 25±15 months of follow-up, VT occurred in 24 patients (53%), but the 6-month VT burden was reduced by ≥75% in 79%. Recurrence rates were low after complete procedural success (18%), but high after both partial success (77%) and failure (73%). Non-complete procedural success was the strongest predictor of VT recurrence (hazard ratio, 8.20; 95% confidence interval, 2.37-28.43; P=0.001). CONCLUSIONS: Although 53% of patients had VT during follow-up, the 6-month VT burden was decreased by ≥75% in 79%. Recurrence rates are low after complete procedural success, but high after both partial success and failure. Non-complete procedural success was the strongest predictor of VT recurrence.

Incessant ventricular tachycardia acutely controlled with off-pump coronary artery bypass surgery and aneurysmal plication.

There are many treatment modalities available to acutely terminate incessant ventricular tachycardia with variable success rates, but some cases tend to prove refractory to all of them. We report a 59-year-old woman presenting with incessant ventricular tachycardia. Echocardiography revealed a large true apical aneurysm and severe left ventricular dysfunction. The arrhythmia was controlled in the operating room after off-pump coronary artery bypass surgery and plication of the apical aneurysm.

Electrical storm in patients with implantable cardioverter-defibrillators: can it be forecast?

The aim of this retrospective study was to determine the prevalence and predictors of electrical storm in 227 patients who had received implantable cardioverter-defibrillators (ICDs) and had been monitored for 31.7 +/- 15.6 months. Of these, 174 (77%) were men. The mean age was 55.8 +/- 15.5 years (range, 20-85 yr), and the mean left ventricular ejection fraction (LVEF) was 0.30 +/- 0.14. One hundred forty-six of the patients (64%) had underlying coronary artery disease. Cardioverter-defibrillators were implanted for secondary (80%) and primary (20%) prevention. Of the 227 patients, 117 (52%) experienced events that required ICD therapy. Thirty patients (mean age, 57.26 +/- 14.3 yr) had > or = 3 episodes requiring ICD therapy in a 24-hour period and were considered to have electrical storm. The mean number of events was 12.75 +/- 15 per patient. Arrhythmia-clustering occurred an average of 6.1 +/- 6.7 months after ICD implantation. Clinical variables with the most significant association with electrical storm were low LVEF (P = 0.04; hazard ratio of 0.261, and 95% confidence interval of 0.08-0.86) and higher use of class IA antiarrhythmic drugs (P = 0.018, hazard ratio of 3.84, and 95% confidence interval of 1.47-10.05). Amiodarone treatment and use of beta-blockers were not significant predictors when subjected to multivariate analysis. We conclude that electrical storm is most likely to occur in patients with lower LVEF and that the use of Class IA antiarrhythmic drugs is a risk factor.

Early septal activation, successful lateral ablation.

The coronary sinus activation pattern is an important clue for the detection of arrhythmia mechanisms and/or localization of accessory pathways. Any change in this pattern during radiofrequency ablation should be evaluated carefully to recognize the presence of another accessory pathway or innocence of the accessory pathway during arrhythmia. Intra-atrial conduction block can change the coronary sinus activation pattern. Negligence regarding this phenomenon can cause irreversible complications. Here we describe a case with left lateral accessory pathway conduction in which intra-atrial conduction block completely reversed the coronary sinus activation pattern.