Optimal method for ablation of atypical AVNRT.

BACKGROUND: Considering that ablation of atypical AVNRT may be unsuccessful after ablation at the right posterior septum, in this study, we aimed to present an optimal method for ablation of atypical AVNRT. Also, we evaluated the efficacy of this technique for preventing recurrences. METHODS: This is a prospective, double-center study. It was conducted on 62 patients with atypical AVNRT referred for radiofrequency ablation. The patients were randomly divided into two groups before ablation: 1-Group A (n = 30): treated with conventional ablation at the anatomic area of the slow pathway; 2-Group B (n = 32): ablation was done 2 mm higher in the septum during fluoroscopy. RESULTS: The mean age of patients in groups A and B were 54 ± 11.7 and 55 ± 12.2, respectively (P = 0.43). In group A, ablation was successful in 24 (80%) patients following right-sided slow pathway ablation, and the remaining patients required further treatment with either a left-side approach (N = 4, 13.3%) or ablation of additional regions (N = 2, 6.7%). In group B, ablation was successful in all patients. After a 48-month follow-up, recurrence of symptomatic atypical AVNRT was detected in 4 (13.3%) patients of group A and none of group B patients (p < 0.001). CONCLUSION: In patients with atypical AVNRT, ablation 2 mm above the conventional area is more promising regarding success rate and recurrence of the arrhythmia.

Signal averaged ECG in patients with early repolarization.

BACKGROUND: Early repolarization (ER) pattern is diagnosed when the J-point is elevated on the patient's electrocardiogram. The aim of this study was to evaluate signal-averaged electrocardiography (SAECG) in patients with ER pattern. METHODS: Subjects were divided into three groups: 1-patients with normal ECG pattern (control group); 2-patients with J-point elevation in the inferior leads; and 3-patients with J-point elevation in non-inferior leads. RESULTS: The mean filtered QRS duration in groups with J-point elevation in inferior leads and non-inferior leads and in the control, was 86.4 ± 23.4 msec, 84.8 ± 26.6 msec, and 85.8 ± 24.8 msec, respectively, indicating no significant difference across the three groups. The mean duration of terminal QRS < 40µV was 21.2 ± 4.2 msec, 22.8 ± 4.6 msec, and 23.1 ± 4.5 msec in the mentioned groups, respectively, without a significant difference between the groups. Additionally, the mean root-mean-square voltage of terminal 40 msec was 34.5 ± 8.3 µV, 35.3 ± 8.6µV, and 35.7 ± 9.2 µV in patients with increased J-point in inferior leads, non-inferior leads, and the control group, respectively, showing no difference between the groups. CONCLUSION: In conclusion, we found that parameters in SAECG did not have any significant difference between patients with ER pattern and healthy individuals. Moreover, we concluded that SAECG cannot distinguish the patients with elevated J-point in inferior leads from non-inferior leads. Overall, SAECG does not appear to be a reliable diagnostic tool for the assessment of ER pattern.

Aortopathic effect of androgenic anabolic steroids.

BACKGROUND: Anabolic androgens have been reported to be associated with cardiovascular complications. One study revealed that increase in vascular stiffness in bodybuilders is associated with anabolic androgens and improvement in vascular function may occur following anabolic androgens discontinuation. The aim of this study was to investigate any possible relation between aortic elastic properties and anabolic androgens. METHODS: Study population was divided into 3 groups: Group-1 [n = 35] consisted of bodybuilders who denied any current or previous use of anabolic androgens. Group-2 [n = 18] was bodybuilders with regular using of anabolic androgens for at least 2 year prior to the start of our study. Group-3 was 13 healthy age-matched sedentary men as a control group. Cardiac echocardiography was performed in the bodybuilders and controls and indexes of aortic function were calculated. RESULTS: Aortic stiffness was approximately twofold higher in anabolic androgens user bodybuilders compared with drug-free bodybuilders [P < 0.001]. CONCLUSION: The present study demonstrates that chronic anabolic androgens use clearly produces significant decrease in the elastic properties of aorta.

Effect of Cardiac Resynchronisation Therapy on Electrical Remodelling.

BACKGROUND: Cardiac resynchronisation therapy (CRT) is an accepted device therapy in patients with low ejection fraction. Beneficial effects of CRT result from mechanical remodelling. Some controversial reports suggest that CRT may also induce electrical remodelling with intrinsic QRS narrowing but still the effect of CRT on electrical remodelling is an issue for debate. The aim of our study was to evaluate the effects of CRT on intrinsic QRS duration. For clarity, our analysis was performed by the signal averaged electrocardiogram (SAECG) which is a high resolution electrocardiographic signal suitable for accurate measurement of QRS duration. Signal averaged electrocardiogram provides a better value of QRS duration compared to 12-lead ECG by the ability to detect ventricular late potentials. METHODS: A total of 48 consecutive patients with severe systolic dysfunction and typical left bundle branch block (LBBB) were enrolled in the study prospectively. Patients were scheduled for CRT-D implantation according to the current guidelines. Intrinsic QRS duration was accurately measured by SAECG before and at least 14 months after CRT implantation. RESULTS: The mean intrinsic QRS duration remained unchanged during follow-up (from 149.9±13.8ms to 149.6±18.4ms; P= 0.3). Among 32 CRT responder patients, the mean intrinsic QRS duration remained unchanged during follow-up. Also, the mean intrinsic QRS duration showed no significant changes in 16 CRT non-responders. CONCLUSION: Structural remodelling induced by CRT does not necessarily translate into decrease of intrinsic ventricular activation. Despite significant left ventricular recovery, electrical characteristics of the left ventricular conduction system cannot generally be expected to recuperate.

Genetic analysis of cardiac SCN5A Gene in Iranian patients with hereditary cardiac arrhythmias.

OBJECTIVE: SCN5A encodes alpha subunit of the major sodium channel (Nav1.5) in human cardiac tissue. Malfunction of this cardiac sodium channel is associated with a variety of cardiac arrhythmias and myocardial inherited diseases. METHODS: Fifty-three members from three families each diagnosed with long-QT syndrome type 3 (LQTS3), Brugada syndrome (BrS), or sick sinus syndrome (SSS) were included in this observational, cross-sectional study. In this study, we analyzed the sequences of coding region of the SCN5A gene. RESULTS: Eleven members of the LQTS family (39%) showed p.Gln1507-Lys1508-Pro1509del mutation, 8 of BrS family (50%) showed p.Arg222Ter nonsense mutation, and 5 of 9 SSS family members (55%) showed a novel p.Met1498Arg mutation in the SCN5A gene. CONCLUSION: p.Gln1507-Lys1508-Pro1509del mutation, p.Arg222Ter nonsense mutation, and p.Met1498Arg in LQTS, BrS, and SSS, respectively, are reported for the first time in the Iranian population. Information regarding underlying genetic defects would be necessary for verifying certain clinically diagnosed arrhythmia types, carrier screening in affected families, and more precise therapy of the patients are required.

Positive Brugada challenge test in V1 R-V3 R as a predictor of malignant prognosis in Brugada patients.

BACKGROUND: The Brugada syndrome is a heterogeneous genetic disease that predisposes to life-threatening ventricular tachyarrhythmias and sudden cardiac death (SCD). The only proven way to prolong the survival of patients with Brugada syndrome is to implant an implantable cardioverter-defibrillator (ICD). This should be implanted for high-risk patients only. METHOD: The patients with type 2 or 3 Brugada ECG pattern were selected for the study. We evaluated 126 patients with Brugada type ECG patterns. Nineteen patients had positive response. Those who had positive result in right side located leads had poorer prognosis. CONCLUSION: Positive flecainide challenge test in right side located pericordial leads can be used as a predictor of poor prognosis in Brugada patients. This can be evaluated in another research for its role in the implantation of ICD. Also, the oral flecainide is not sensitive enough to rule out the presence of Brugada syndrome and it should not be trusted as a screening test for suspected cases.

Clinical and electrocardiographic predictors of positive response to the intravenous sodium channel blockers in patients suspected of the Brugada syndrome.

BACKGROUND/OBJECTIVES: Sodium channel blockers are used to unmask the diagnostic ECG pattern of the Brugada syndrome (BrS) in case of a non-diagnostic baseline ECG. The aim of the study was to determine clinical and ECG predictors of a positive challenge test in patients suspected to the BrS. METHODS: A total of 106 consecutive patients (91 men; mean age, 35 ± 12 years) suspected of the BrS underwent the intravenous sodium channel blocker challenge test with procainamide or flecainide. RESULTS: Of the 106 patients, positive tests were detected in 20 (19%) patients. During test, a transient episode of a second-degree atrioventricular block and isolated ventricular ectopies were observed in 1 (0.9%) and 2 (1.9%) patients, respectively. A QRS prolongation ≥ 30% was observed in 4 (3.8%) patients. Baseline QRS duration in V1 ≥ 110 ms had a sensitivity of 70% and a specificity of 80% for a positive response. An ST-segment elevation ≥ 0.17 mV in V2 had a sensitivity of 60% and a specificity of 82% for a positive response. Of the multiple clinical and ECG variables entered into a binary logistic regression analysis, a history of syncope (P=0.001), previous cardiac arrest (P=0.001), baseline QRS duration in V1 ≥ 110 ms (P=0.001), and baseline ST-segment elevation in V2 ≥ 0.17 mV (P=0.012) emerged as the independent predictors of a positive response to the intravenous challenge with sodium channel blockers. CONCLUSION: The results of the sodium channel blocker challenge test can be predicted by clinical presentation and baseline ECG features.

Idiopathic right atrial enlargement.

A 26-year-old man presented with lower extremity edema and abdominal protrusion associated with dyspnea for 5 years, which had increased 7 months earlier. Echocardiography demonstrated a huge right atrium of 19.5 × 15.2 cm with a thick smoke pattern and severe tricuspid regurgitation. Magnetic resonance imaging confirmed intact pericardium. A pulmonary perfusion scan demonstrated multiple perfusion defects, suggesting recurrent small pulmonary emboli. Idiopathic enlargement of the right atrium was diagnosed. The patient declined surgery.

Value of the aVR lead in differential diagnosis of atrioventricular nodal reentrant tachycardia.

AIMS: Despite the several electrocardiographic (ECG) criteria, misclassification may still occur in differential diagnosis of the regular paroxysmal supraventricular tachycardia (PSVT). The aim of the present study was to evaluate the diagnostic accuracy of the aVR lead in ECG differentiation of atrioventricular nodal reentrant tachycardia (AVNRT) and atrioventricular reciprocating tachycardia (AVRT). METHODS AND RESULTS: A 12-lead ECG was recorded in 150 consecutive patients (96 women, mean age, 45 ± 13.5 years) with drug-refractory regular PSVT during both sinus rhythm and tachycardia. All ECGs were reviewed by two experienced electrophysiologists who had no knowledge of the tachycardia mechanism. The ECG recordings were evaluated for standard criteria as well as our newly proposed criterion of pseudo-r' in the lead aVR. Mechanism of arrhythmia was confirmed by the electrophysiological study and the successful catheter ablation. Patients with AVNRT were older (50 ± 10 vs. 37 ± 15 years, P = 0.001), predominantly female (71 vs. 53%, P = 0.03), and presented with slower tachycardia (175 ± 25 vs. 186 ± 26 b.p.m., P = 0.01). Among the ECG criteria of the AVRT diagnosis, visible P-wave with RP interval ≥ 100 ms had highest diagnostic accuracy (sensitivity 79%, specificity 87%, and positive predictive value 79%). For AVNRT diagnosis, pseudo-r' in aVR had a higher sensitivity, specificity, and predictive values compared with the conventional criteria of the pseudo-r' in V1 and pseudo-s in inferior leads (all P < 0.05). CONCLUSIONS: New criterion of pseudo-r' in lead aVR appears to be more accurate than the standard ECG criteria for ECG diagnosis of AVNRT.

The effect of left ventricular (LV) remodeling on ventricular arrhythmia in cardiac resynchronization therapy (CRT-D) patients (antiarrhythmic effect of CRT).

BACKGROUND: In patients with low ejection fraction and ventricular dyssynchrony, cardiac resynchronization therapy (CRT) is an accepted therapeutic modality. In these patients, CRT can improve the quality of life and exercise tolerance in addition to improved survival. On the other hand, antiarrhythmic effects of CRT is a place of debate. METHOD: In this study, we evaluated the effect of CRT-induced reverse remodeling on ventricular arrhythmia in heart failure patients. Patients with CRT were divided to two groups of responders and nonresponders. Responders were those with reduction of LVESD of more than 10% or increase in LVEF of more than 5%. They were visited and device analysis was performed during the follow-up. RESULTS: One hundred and nineteen patients were enrolled in this study. Those with reverse remodeling experienced fewer ventricular arrhythmias after two years of follow-up (N = 2 vs 11, P = 0.001). CONCLUSION: Reverse remodeling associated with CRT implantation can result in decreased frequency of ventricular arrhythmias.

Electrocardiographic, electrophysiologic, and anatomical features of ventricular tachycardia originating from noncoronary cusp.

In this article, we report 2 young patients (a 15-year-old adolescent girl and a 25-year-old man) with drug-refractory palpitations. Admission electrocardiograms showed runs of ventricular tachycardia with left bundle-branch block morphology, left inferior axis, early precordial QRS transition, and positive QRS complex in lead I. In right ventricular mapping, the earliest activation site was found in the His bundle region. Aortic root mapping showed a very early fractionated ventricular signal with large atrial potential and no His potential in the noncoronary cusp region. Radiofrequency energy application in this region resulted in tachycardia termination within 5 to 10 seconds. During a 3- to 6-month follow-up period, the patients remained asymptomatic, and the electrocardiogram showed no ventricular arrhythmias.

Pericardial PEComa: echocardiographic features.

The patient was a 19 year old man referred to our center due to progressive effort dyspnea and left sided pleuritic chest pain for 1 month. Echocardiographic examination showed a posteriorly located, giant, well demarcated mass, that compresses the left atrium. It was encased by moderate pericardial effusion. Histhopathological analysis disclosed neoplastic cells arranged around blood vessels with immunoreactivity for HMB-45 indicative of PEComa (Perivascular Epitheloid Cell differentiation). Six month follow up was uneventful. Up to the best of our knowledge, this is the first case of pericardial PEComa reported in the literature.

Acquired aortoventricular tunnel: a rare complication of infective endocarditis.

A 26-year-old man presented to emergency department with fever associated with night sweating and weight loss since 2 months prior to admission. He was an intravenous heroin user admitted for infective endocarditis of aortic valve 1 year ago. Transthoracic echocardiography followed by the transesophageal study showed bileaflet aortic prosthesis with normal transvalvular gradient and severe paravalvular aortic insufficiency. A pseudoaneurysm of intervalvular fibrosa connecting left ventricular outflow tract (LVOT) to noncoronary sinus of valsalva was detected.

aVR sign as a risk factor for life-threatening arrhythmic events in patients with Brugada syndrome.

BACKGROUND: Risk stratification in Brugada syndrome (BS) is controversial, especially in asymptomatic individuals. OBJECTIVE: The aim of this study was to evaluate the significance of lead aVR in patients with BS. METHODS: Twenty-four patients with the electrocardiogram pattern of BS (24 male, mean age 32.1 +/- 13.6 years) and 24 healthy age- and gender-matched controls were studied. RESULTS: Thirteen patients were symptomatic. The R-wave amplitude or R/q ratio in lead aVR was significantly greater in patients experiencing a recurrence compared with those who did not. The aVR sign was defined as R wave >/= 0.3 mV or R/q >/= 0.75 in lead aVR. Most of the recurrences (78%) were in patients with present aVR sign; 84% of BS patients with present aVR sign had events during follow-up. In contrast, only 27% of BS patients with absent aVR sign had events during follow-up. CONCLUSION: Our study shows significant correlation between a prominent R wave in lead aVR (aVR sign) and risk for development of arrhythmic events in BS. In the presence of BS, prominent R wave in lead aVR may reflect more right ventricular conduction delay and subsequently more electrical heterogeneity, which in turn is responsible for a higher risk of arrhythmia.

Clinical predictors of atrial fibrillation in Brugada syndrome.

AIMS: Atrial arrhythmias have been reported in patients with Brugada syndrome. The aim of this study was to evaluate clinical predictors of atrial fibrillation (AF) in Brugada syndrome. METHODS AND RESULTS: Patients diagnosed with Brugada ECG pattern were enrolled in the study. Type 1, 2, and 3 Brugada ECG pattern was found in 28, 56, and 31 patients, respectively. A total of 85 healthy age and gender-matched subjects were selected as a control group. Mean age, maximum P-wave duration (P(max)), P-wave dispersion (P(disp)), and left atrial dimension were not significantly different between patients and controls. There were no differences between P(max), P(disp), and left atrial dimension of the type 1, 2, and 3 Brugada patients. Spontaneous paroxysmal AF was detected in 15 of 28 type 1 Brugada patients (53%) and none of the type 2 and 3 Brugada patients. All 15 patients with AF had at least one episode of paroxysmal AF and none of the patients showed persistent or chronic AF. All 15 patients who had paroxysmal AF had previous life threatening cardiac events. In contrast, paroxysmal AF did not occur in type 1 Brugada patients without previous life threatening cardiac events. In multiple regression analysis, only the occurrence of previous life threatening cardiac events was a risk factor for paroxysmal AF (P = 0.0001). CONCLUSION: It is concluded that the most important predictor of AF in Brugada syndrome is the occurrence of previous life threatening cardiac events.

Left atrial volume: a novel predictor of hepatopulmonary syndrome.

OBJECTIVES: We studied patients with hepato-pulmonary syndrome (HPS). We found that HPS is frequently present in patients with left atrial enlargement. The aim of this prospective study was to evaluate the possible correlation between left atrial volume and HPS. METHODS: Adult patients (>18 yr old) with biopsy proven liver cirrhosis who were referred for liver transplantation were enrolled in the study. Diagnosis of HPS was established when the following points were fulfilled: (a) the presence of chronic liver disease, (b) increased alveolar-arterial difference (AaDO(2)), (c) intrapulmonary vascular dilatation, and (d) absence of primary cardiac or pulmonary disease. RESULTS: We enrolled 41 patients (mean age 47.1 +/- 10.6 yr) diagnosed with HPS. Also 108 Child-Pugh score matched cirrhotic patients (mean age 49.2 +/- 9.3 yr) who have negative contrast echocardiography and normal age-related AaDO(2) were selected as a control group for the purpose of comparison of left atrial volume (LAV). LAV was significantly greater in patients with HPS compared to the control group (55.1 +/- 7.5 mL vs 37.1 +/- 9.3 mL, P < 0.05). The area under the receiver-operating characteristic (ROC) curve for LAV was 0.903 (Cut point >/= 50 mL, sensitivity 86.3%, specificity 81.2%). CONCLUSION: In the context of liver cirrhosis, LAV >/= 50 mL is a simple and feasible parameter to detect HPS.

Prevalence of Brugada sign in patients presenting with palpitation in southern Iran.

AIMS: Brugada syndrome is a cardiac channel abnormality that is associated with a high risk of ventricular fibrillation and sudden cardiac death and characterized by an electrocardiographic pattern of right bundle branch block and transient or persistent ST-segment elevation in leads V1-V3. No data regarding the frequency of Brugada syndrome exist in an Iranian population. The aim of this study was to determine the frequency of Brugada-type ECG pattern in southern Iran. METHODS AND RESULTS: All patients presenting with palpitation were enrolled in the study. A Brugada-type ECG pattern was determined according to the criteria recommended by European Heart Association Molecular Basis of Arrhythmias Study Group. A total of 3895 patients (mean age 38.2 +/- 11.9 years, 54% women) met all study criteria. One hundred patients (2.56%) had Brugada-type ECG pattern. Of these, 21 patients (0.54%) had definite Brugada sign (Type 1 or Types 2 and 3 with conversion to Type 1 following procainamide test). Of 21 patients with definite Brugada sign, eight had Brugada syndrome, four had history of syncope, two had coved-type ECG in the family, one had polymorphic ventricular tachycardia, and one had history of sudden cardiac death in the family. Five patients underwent ICD implantation. The incidence of a Brugada-type ECG pattern was 2.43% in subjects between 17 and 30 years and 0.13% in subjects >30 years (P = 0.01). CONCLUSION: Frequency of Brugada sign in an Iranian population presenting with palpitation is greater than some European countries and lower than a Japanese urban population.