Malini Govindan

Utility of high and standard right precordial leads during ajmaline testing for the diagnosis of Brugada syndrome

Aims The authors sought to assess the value of the high right precordial leads (RPL) to detect the Type I Brugada ECG pattern in patients suspected of carrying Brugada syndrome (BrS). Methods Ajmaline testing using 15-lead ECGs was performed in 183 patients suspected of carrying BrS. Standard 12-lead ECG with V1–V3 recorded from the fourth intercostal space and an additional three leads placed over V1–V3 recorded from the third intercostal space were analysed. ECGs were analysed for a Type I ECG pattern in either the standard or high RPLs. Results Of the 183 tests, 31 (17%) were positive, and 152 were negative. In all positive studies, at least one high RPL became positive. In 13/31 (42%) cases, the Type I ECG pattern could be observed only in the high RPLs. Standard or high V3 were never positive before standard or high V1–V2. In seven patients, a Type I pattern was seen in one standard and one high RPL (vertical relationship). Conclusions The high RPLs are more sensitive than the conventional 12-lead ECG alone and initial observations suggest that they remain specific for BrS, while standard and high lead V3 offer redundant data. A vertical relationship of type 1 patterns may have a similar diagnostic value to that of a horizontal pair.

Validation of echocardiographic left atrial parameters in atrial fibrillation using the index beat of preceding cardiac cycles of equal duration

BACKGROUND The clinical assessment of left atrial function during atrial fibrillation is challenging and often inaccurate because of the beat-to-beat variability in the cycle length. The aim of this study was to validate the use of an index beat, the beat following two preceding cardiac cycles of equal duration, for the measurement of left atrial functional indices, including area, volume, and expansion index. The index beat was compared with the conventional but time-consuming method of averaging multiple consecutive cardiac cycles. METHODS Thirty patients with persistent or permanent atrial fibrillation were studied using two-dimensional echocardiography, and left atrial indices were measured from the average of 17 consecutive cardiac cycles compared with that of an index beat taken from outside of these 17 cycles. RESULTS The index beat showed good correlation with the averaging technique, and comparison of the two methods showed them to be interchangeable. Clinically, the differences in left atrial functional indices between the two methods were minor. CONCLUSIONS Use of the index beat to measure dynamic left atrial function in atrial fibrillation can easily be performed and is as accurate as and less time consuming than the onerous method of averaging of multiple cardiac cycles.

Significance of QRS prolongation during diagnostic ajmaline test in patients with suspected Brugada syndrome

BACKGROUND Current consensus documents on Brugada syndrome recommend the diagnostic intravenous administration of a Na-channel blocker to be stopped when the QRS prolongs to > or =130% of baseline, presumably because of increased arrhythmic risk. OBJECTIVE This study sought to assess QRS prolongation during ajmaline testing and its relation to arrhythmic risk. METHODS We analyzed an electrocardiographic (ECG) database collected during ajmaline testing in 148 patients (92 men, age 36 +/- 15 years). The QRS was measured at baseline and during the 1st to 7th, 10th, and 15th minute after the beginning of ajmaline administration. RESULTS The average QRS prolongation was 36% +/- 16% (range 9% to 88%), not significantly different between positive (n = 30) and negative (n = 118) tests. QRS prolonged to > or =130% during 16 (55%) positive and 71 (61%) negative tests (P = .50), with no clinical side effects. The incidence of ventricular arrhythmias was not significantly different between patients with and without QRS prolongation. Short runs (3 to 8 complexes) of nonsustained ventricular tachycardia occurred in 3 patients with QRS prolongation > or =130%. In 40% of positive tests, prolongation > or =130% occurred earlier by >1 minute than diagnostic Brugada ECG changes, i.e., early termination of the test could possibly have resulted in false-negative outcomes. CONCLUSION QRS prolongation > or =130% occurs in >50% of all tests. In 40% of positive tests it occurs before diagnostic ECG changes. Always terminating the test when QRS prolongs > or =130% could possibly result in loss of important diagnostic information. It is appropriate to adjust the criteria for early termination of the test to the baseline QRS and possibly other factors.

Diagnostic utility of bipolar precordial leads during ajmaline testing for suspected Brugada syndrome

BACKGROUND Leads V(1) and V(2) recorded from the standard position (fourth intercostal space) have insufficient sensitivity to detect the diagnostic type 1 Brugada ECG pattern. OBJECTIVE The purpose of this study was to compare the sensitivity of bipolar leads with a positive pole at V(2) and a negative pole at V(4) or V(5) with that of the standard unipolar lead V(2) for detection of the type 1 Brugada pattern. METHODS We analyzed digital 15-lead ECGs (12 standard leads plus leads V(1) to V(3) recorded from the third intercostal space [V(1h) to V(3h)]) acquired during diagnostic ajmaline testing in 128 patients (80 men, age 37 +/- 15 years) with suspected Brugada syndrome and standard 12-lead ECGs recorded in 229 healthy subjects (111 men, age 33 +/- 4 years). Bipolar leads between V(2) (positive pole) and V(4) or V(5) (leads V(2-4), V(2-5)) were derived by subtracting leads V(4) and V(5) from V(2). All ECGs were examined for the presence of type 1 Brugada pattern. RESULTS During 21 (16.4%) positive ajmaline tests, type 1 pattern was observed in lead V(2h) during 20 tests (95.2%) and in V(2) during 10 tests (47.6%). Type 1 pattern appeared in lead V(2-4) or V(2-5) in all tests when it was present in V(2) and in seven tests during which it was observed in lead V(2h) but not V(2) (17 tests [81%]). Type 1-like pattern was observed in lead V(2-4) or V(2-5) during two nonpositive tests (1.9%) and in one healthy subject (0.4%). CONCLUSION Bipolar leads V(2-4) and V(2-5) are more sensitive than lead V(2) for detection of the type 1 Brugada pattern.

Specificity of elevated intercostal space ECG recording for the type 1 Brugada ECG pattern.

Background: Right precordial (V1–3) elevated electrode placement ECG (EEP‐ECG) is often used in the diagnosis of Brugada syndrome (BrS). However, the specificity of this has only been studied in smaller studies in Asian populations. We aimed to study this in a larger European population.

Impaired Biventricular Deformation in Marfan Syndrome: A Strain and Strain Rate Study in Adult Unoperated Patients

Objective: To investigate the presence of any regional myocardial deformation abnormalities in Marfan syndrome (MFS) and determine the benefits of using advanced echocardiography compared to conventional techniques. Background: Myocardial dysfunction in MFS may be caused by extracellular matrix remodeling thus, resulting in uniform reduced functionality. However, increased aortic stiffness may cause segmental ventricular abnormalities. Strain rate imaging (SRI) constitutes a validated technique to assess regional deformation in various clinical conditions. With this in mind, we aimed to investigate biventricular function in MFS using SRI. Methods: Forty‐four MFS patients (mean age 30 ± 12 years, 26 men) and 49 controls without valvular disease were examined using SRI. Ejection fraction (EF) was calculated by the Simpsons biplane method. Biventricular deformation was assessed by measuring strain/strain rate. Strain values were divided by left ventricular (LV) end‐diastolic volume to adjust LV deformation for geometry changes providing a strain index (SI). Aortic stiffness was evaluated using the β‐stiffness index. Results: EF (%) was reduced in MFS patients (59 ± 5 vs 72 ± 4, P < 0.001), whereas β‐stiffness was increased (P < 0.001). LV radial and LV and right ventricular (RV) long‐axis strain values (%) were reduced in the patient group (70 ± 17 vs 93 ± 10; 19 ± 2 vs 25 ± 2; 30 ± 9 vs 36 ± 8, respectively, P < 0.001). Strain rate measurements were also reduced (P < 0.001). In a multiple regression analysis, MFS diagnosis was negatively associated with LV SI (−0.262 [−0.306, −0.219], P < 0.001). β‐Stiffness was negatively associated with SI obtained from the septum, inferior and anterior walls. ROC analyses demonstrated that SRI, when compared with conventional echocardiography, had higher sensitivity and specificity in predicting biventricular dysfunction in MFS. Conclusions: Our study showed a uniform reduction in biventricular deformation in MFS. These findings suggest that assessment of myocardial function using advanced echocardiographic techniques could be more accurate in MFS patient evaluation than conventional echocardiography alone. (Echocardiography 2011;28:416‐430)

Assessment of aortic stiffness in marfan syndrome using two-dimensional and Doppler echocardiography.

Background: Extracellular matrix remodeling in the aortic wall results in increased aortic stiffness (AoS) in Marfan syndrome (MFS). Pulsed‐wave velocity (PWV) constitutes the best indirect AoS measurement. We aimed to assess PWV in MFS patients using two‐dimensional (2D) and Doppler echocardiography. Methods: Thirty‐one MFS patients, (mean age 31 ± 14 years, 16 men) and 31 controls were examined. Blood flow was recorded in the aorta near the aortic valve and immediately after in the descending aorta with simultaneous electrocardiography. PWV was calculated by dividing the distance between the two sample volume positions (D) by the time difference (TD) between the intervals from the QRS start to the ascending and descending aortic flow onsets. B‐stiffness was also measured. Results: TD (described in “Methods” section) and, aortic arch length were significantly increased in MFS patients, P < 0.001. Thus, PWV values were significantly higher in patients when compared with controls, 7.20 m/s (5.12, 9.43) versus 4.64 m/s (3.37, 6.24), P < 0.001. B‐stiffness was also significantly increased in MFS patients; 5.15 (3.69, 7.65) versus 2.44 (1.82, 3.66), P < 0.001. Multiple regression analysis showed a positive association with MFS diagnosis and age, (P = 0.002 and 0.009, respectively). Reproducibility of PWV measurements was <5%. Conclusions: AoS was significantly higher in MFS patients as expected. Our data demonstrated that PWV measurements can be performed, in the absence of serious musculoskeletal abnormalities in MFS adults, as part of a cardiac ultrasound scan. This technique can be helpful in diagnosis and management in MFS. (Echocardiography 2011;28:29‐37)

Brugada-Like Changes in the Peripheral Leads during Diagnostic Ajmaline Test in Patients with Suspected Brugada Syndrome

Background: Although cases of Brugada‐type electrocardiographic (ECG) pattern in peripheral (limb) leads have been reported (“atypical” Brugada syndrome [BS]), their incidence in patients investigated for BS is unknown.

Characterization of early repolarization during ajmaline provocation and exercise tolerance testing

BACKGROUND Early repolarization (ER) in the inferior electrocardiogram leads is associated with idiopathic ventricular fibrillation, but the majority of subjects with ER have a benign prognosis. At present, there are no risk stratifiers for asymptomatic ER. OBJECTIVE To examine the response to ajmaline provocation and exercise in potentially high-risk subjects with ER and without a definitive cardiac diagnosis. METHODS Electrocardiographic data were reviewed for ER at baseline and during ajmaline and exercise testing in 229 potentially high-risk patients (mean age 37.7±14.9 years; 55.9% men). ER was defined as J-point elevation in ≥2 consecutive leads and stratified by type, territory, J-point height, and ST-segment morphology. RESULTS Baseline ER was present in 26 (11.4%; 19 men) patients. During ajmaline provocation and exercise, there were no new ER changes. ER with rapidly ascending ST-segment and lateral ER consistently diminished. There were 7 patients with persistent ER during ajmaline and/or exercise. They were all men with inferior or inferolateral ER and horizontal/descending ST segment. Those with persistent ER during exercise were more likely to have a history of unexplained syncope than those in whom ER changes diminished (P<.01). Subtle nondiagnostic structural abnormalities were demonstrated in 3 of these patients. CONCLUSIONS ER with horizontal/descending ST-segment morphology in the inferior or inferolateral leads that persists during exercise is more common in patients with prior unexplained syncope and may identify patients at higher risk of arrhythmic events. ER that persists during ajmaline provocation and/or exercise may reflect underlying subtle structural abnormalities and should prompt further investigation.

Prognostic value of left atrial expansion index and exercise-induced change in atrial natriuretic peptide as long-term predictors of atrial fibrillation recurrence.

AIMS We propose to assess the value of exercise-induced change in N-terminal-pro atrial natriuretic peptide (NT-proANP) and left atrial expansion index (LAEI) in predicting AFR after cardioversion and their effect on AF-free survival. METHODS AND RESULTS Fifty-five patients with persistent AF of <18 months duration needing cardioversion were recruited for the study. Fifty-four patients were successfully cardioverted. At 3 months 28/54 (51%) were in SR and at 12 months 21/53 (39%). On multivariate analysis, only exercise-induced change in NT-proANP and LAEI were found to be predictive of AFR up to 12 months post-cardioversion and had an effect on AF-free survival. N-terminal-pro brain natriuretic peptide was elevated in all persistent AF patients but did not predict recurrent AF. CONCLUSIONS Left atrial expansion index and exercise-induced atrial natriuretic peptide change show promise as predictors of AFR after cardioversion. These predictors may identify patients at an early stage in their disease with intact neurohumoral feedback systems and less advanced atrial remodelling. Further studies are required to confirm these findings.