Analysis of ST segment depression in supraventricular tachycardia and its relationship with underlying mechanism.

BACKGROUND: Electrocardiographic diagnosis of causes of supraventricular tachycardia (SVT) is sometimes difficult and application of routine algorithms can lead to misdiagnosis in as many as 37 % of patients. ST segment depression may be useful in diagnosing the nature of SVT. METHODS: We reviewed surface electrocardiogram (ECG) characteristics of 300 patients having SVT with 1:1 AV relationship and correlated findings with electrophysiology study (EPS) findings. Final diagnosis of AVNRT (Atrioventricular nodal reentrant tachycardia), Orthodromic AVRT (atrioventricular reentrant tachycardia) and atrial tachycardia (AT) was correlated with ECG parameters like heart rate, ST segment depressions and QRS morphology. RESULTS: Out of 300 patients, majority patients included in study, were having AVNRT or AVRT. ST depression predicted AVRT if the ST depression was ≥ 2 mm (overall sensitivity of 38.3 % and specificity of 93.8 % to predict AVRT) and was downsloping in morphology (sensitivity of 36.9 % and specificity of 94.7 % to predict AVRT). At heart rates ≥214 beats per minute (bpm) as measured by 7 small squares of ECG at 25 mm/s, downsloping ST depression ≥2 mm had a sensitivity 37.9 % of and specificity of 89.2 % to predict AVRT. At heart rate <214 bpm, downsloping ST depression ≥2 mm had sensitivity of 37.2 % and specificity of 96.5 % to predict AVRT. Downsloping ST depression of ≥2 mm helps to differentiate AVNRT from AVRT. CONCLUSION: A downsloping ST segment depression ≥2 mm predicted SVT being an AVRT and can be used as a useful criteria in diagnosing the tachycardia.

Incidence, clinical characteristics, electrophysiological characteristics and outcomes of patients with baseline PR prolongation undergoing radiofrequency ablation for Atrioventricular nodal reentrant tachycardia.

AIMS AND OBJECTIVES: Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common supraventricular tachycardia (SVT). Prolonged PR interval(>200 ms) on baseline electrocardiogram (ECG) is uncommon in such patients. The aim of the current study was to evaluate the incidence, clinical, electrophysiological characteristics, and outcomes of patients with baseline prolongation of PR interval undergoing radio-frequency ablation (RFA) for AVNRT. METHODS: Over 10 years, out of the total number of 1435 patients with diagnosed AVNRT, 16 patients had prolonged PR intervals at baseline. All underwent elective RFA. A retrospective analysis of clinical, and electrophysiological characteristics and outcomes was done. The PR interval and atria-ventricular block cycle length values were compared with those patients with a normal interval at baseline and had undergone a successful slow pathway modification for AVNRT. RESULTS: Out of 1435 patients with AVNRT, 16 (0.9 %) patients had baseline PR prolongation on ECG. The mean(+SD) age of the study population was 62.9 + 15.9 years. 10 (62.5 %) were males. The average PR interval was 264.2 + 24.1 ms. Slow fast AVNRT was seen in all. The anatomical site of success for ablation was the lower part of Koch's triangle in all patients. During ablation, a good sustained junctional rhythm was noted in all, with no AV (Atrioventricular) block or PR prolongation noted during ablation in any of the patients. PR interval decreased by more than 20 ms in 10 (62.5 %) patients. AVBCL (AV node block cycle length) increased on an average of 58.7 ms post-ablation. Only one patient developed AV block on follow-up. CONCLUSION: A prolonged PR interval on baseline ECG is uncommon in patients with AVNRT. In these patients, slow pathway modification can be done safely and effectively. AVBCL (AV node block cycle length) increases immediately post-ablation. The risk of AV block though low persists on follow-up.

Incidence, clinical, electrophysiological characteristics and outcomes of patients with Wolff-Parkinson-White syndrome and atrial fibrillation.

AIMS AND OBJECTIVES: Atrial fibrillation (AF) with preexcitation can be life threatening. Our study evaluated the incidence, clinical features, electrophysiologic characteristics and outcomes of patients presenting with AF and fast ventricular rates associated with an antegrade conducting accessory pathway. METHODS: Hospital data of patients who had undergone electrophysiology study and radiofrequency ablation for AF and Wolff-Parkinson-White (WPW) syndrome was retrospectively evaluated over 10 years and prospective data was further collected over 1 year. Out of 2876 patients undergoing electrophysiology study, 320 patients had manifest preexcitation on ECG. Forty one patients who had presented with AF and fast ventricular rates were included in the study. RESULTS: Forty one (12.8%) patients out of 320 patients of WPW syndrome patients presented with AF and fast ventricular rates. Mean age of presentation was 38.5 ± 12.3 yrs. Twenty nine (72.5%) were male. Most common presenting features were palpitations, presyncope and syncope. Twenty eight (71.1%) patients were electrically cardioverted on presentation, of which two patients having narrow complex tachycardia, when given adenosine, developed AF and fast ventricular rates and had to be electrically cardioverted. Intravenous amiodarone converted AF to sinus rhythm in 11 (28.9%) patients. Right postero-septal pathway (33.3%) followed by coronary sinus epicardial pathway (22.9%) were the most commonly located pathways associated with AF. Five (12.2%) patients had multiple pathways. CS diverticulum was seen in 6 (14.7%) patients. Ablation was done during AF in 6 (14.7%) patients. All except one had immediate successful ablation. One patient had a recurrence of preexcitation on follow up and successfully ablated during redo procedure. CONCLUSION: AF with WPW syndrome is not uncommon. AF is commonly associated with posteriorly located accessory pathways, CS diverticulum and multiple pathways. Radiofrequency ablation has good outcomes.

Pseudo-Kussmaul's Sign in Atrioventricular Nodal Reentry Tachycardia: A Prospective, Cohort Study.

Aims: To study the respiratory variation of right atrial (RA) pressures at baseline and during atrioventricular nodal reentry tachycardia (AVNRT). Methods: Of the 23 patients screened, 16 participants with typical AVNRT were included in the study. After ensuring adequate hydration, baseline RA pressures were measured as the height of 'a' and 'v' waves. The patients were asked to take deep breaths, and the measurements were taken in both inspiration and expiration. Results: Of the 16 participants, 14(87.5%) showed a normal fall in the height of 'a' and 'v' waves with inspiration, 1(6.25%) showed no change and 1(6.25%) showed a rise in height at baseline, p <0.01. During induced AVNRT, the 'a' and 'v' wave heights increased in 8(50%), remained same in 6(37.5%) and showed a normal fall in 2(12.5%), p = 0.07 for 'a' waves and p = 0.09 for 'v' waves. When the magnitude and direction of change in 'a' and 'v' wave height at baseline was compared with AVNRT, it showed a significant difference with 13(81.25%) participants demonstrating positive Pseudo-Kussmaul's sign, p <0.01. Mean age was numerically higher in those with a more considerable inspiratory rise in RA pressures but was not statistically significant, χ2(2) = 3.1, p = 0.21. Conclusions: Pseudo-Kussmaul's sign does occur in a substantial number of patients during AVNRT. Clinical appreciation of this phenomenon is possible in half to three-fourth of patients, provided the mean RA pressures are low enough for the variation to be visible in the neck.

Fluorodeoxyglucose-positron emission tomography (FDG-PET) of carotid arteries and non-alcoholic fatty liver disease (NAFLD): An analytical cross-sectional study from a teaching hospital, Kerala, South India.

Introduction: Evidence related to carotid artery F-fluorodeoxyglucose-positron emission tomography (FDG -PET) and non-alcoholic fatty liver disease (NAFLD) is limited from a low-resource setting. The present study aims to examine the association between FDG-PET uptakes by the carotid arteries in patients having different grades of NAFLD. Materials and Methods: An analytical cross-sectional study was done in a tertiary care center in South India for 1 year. Sonographically confirmed NAFLD patients of the age group 18 years and above were consecutively enrolled for the study after getting informed consent. Anthropometric measurements, ultrasonography for identifying the grades of fatty liver and FDG-PET were performed in the study participants. The data for the study were collected by the research personnel and entered in Microsoft Excel. The data were analyzed in the IBM SPSS version 20.0 software. Results: A total of 24 patients were in the final analysis. The mean age of patients in this study was 56.79 (11.26) years. Among the 24 patients, 95.83% (n = 23) were males. The mean FDG-PET uptake in the carotids was 1.75 (0.42) units. The FDG uptake was higher in the moderate NAFLD group (1.46 [0.40] v/s 2.04 [0.14]) and the difference was statistically significant with P < 0.001. The FDG uptake between the coronary artery disease (CAD) with NAFLD and non CAD with NAFLD groups was not statistically significant (1.60 [0.46] v/s 1.86 [0.36], P = 0.17). The FDG uptake in CAD patients with mild and moderate NAFLD had no statistical significance between the two groups (1.43 [0.45] v/s 2.00 [0.00], P= 0.06). Conclusion: The findings of this study showed increased uptake of FDG-PET in carotids in subjects with moderate fatty liver when compared with those with mild fatty liver.