Iron Deposition following Chronic Myocardial Infarction as a Substrate for Cardiac Electrical Anomalies: Initial Findings in a Canine Model

Purpose: Iron deposition has been shown to occur following myocardial infarction (MI). We investigated whether such focal iron deposition within chronic MI lead to electrical anomalies. Methods: Two groups of dogs (ex-vivo (n = 12) and in-vivo (n = 10)) were studied at 16 weeks post MI. Hearts of animals from ex-vivo group were explanted and sectioned into infarcted and non-infarcted segments. Impedance spectroscopy was used to derive electrical permittivity () and conductivity (). Mass spectrometry was used to classify and characterize tissue sections with (IRON+) and without (IRON-) iron. Animals from in-vivo group underwent cardiac magnetic resonance imaging (CMR) for estimation of scar volume (late-gadolinium enhancement, LGE) and iron deposition (T2*) relative to left-ventricular volume. 24-hour electrocardiogram recordings were obtained and used to examine Heart Rate (HR), QT interval (QT), QT corrected for HR (QTc) and QTc dispersion (QTcd). In a fraction of these animals (n = 5), ultra-high resolution electroanatomical mapping (EAM) was performed, co-registered with LGE and T2* CMR and were used to characterize the spatial locations of isolated late potentials (ILPs). Results: Compared to IRON- sections, IRON+ sections had higher, but no difference in. A linear relationship was found between iron content and (p1.5%)) with similar scar volumes (7.28%±1.02% (Iron (1.5%)), p = 0.51) but markedly different iron volumes (1.12%±0.64% (Iron (1.5%)), p = 0.02), QT and QTc were elevated and QTcd was decreased in the group with the higher iron volume during the day, night and 24-hour period (p<0.05). EAMs co-registered with CMR images showed a greater tendency for ILPs to emerge from scar regions with iron versus without iron. Conclusion: The electrical behavior of infarcted hearts with iron appears to be different from those without iron. Iron within infarcted zones may evolve as an arrhythmogenic substrate in the post MI period

Bundle branch reentry: A rare mechanism of ventricular tachycardia in endomyocardial fibrosis, without ventricular dilation

Introduction: Bundle branch reentry as a mechanism of ventricular tachycardia (VT) in endomyocardial fibrosis (EMF) is not described. Case report: A 52-year-old woman with left ventricular (LV) EMF had VT needing cardioversion. She had mitral regurgitation and left bundle branch block, but no LV dilation or heart failure. During electrophysiological study, clinical VT could be easily induced, and it was confirmed to be bundle branch reentrant VT (BBRVT). She was treated with ablation of the right bundle branch. Conclusion: BBRVT can occur in EMF even without cardiac dilatation. Its recognition is important, as radiofrequency ablation can be curative

Rheumatic mitral stenosis with incidental Wolff–Parkinson–White syndrome: A rare association. Treated by percutaneous transmitral commissurotomy and radiofrequency ablation

The combination of Wolff–Parkinson–White (WPW) syndrome and rheumatic mitral stenosis (MS) is rare in clinical practice. The management of this condition primarily depends on the clinical picture. We describe a 26-year-old male patient with no significant previous medical history and who came for a routine medical assessment before entrance to a police academy service. He was found to have rheumatic MS and WPW

Prevalence of electrocardiographic changes in patients with acute aneurysmal subarachnoid hemorrhage and their relationship with outcome

Background Electrocardiographic (ECG) alterations occurring after subarachnoid hemorrhage (SAH) have been described frequently, but the prognostic significance of these changes has not been well characterized. Aim and Objectives To report the prevalence and patterns of ECG alterations in patients with acute aneurysmal SAH and to study the relationship between ECG alterations and the neurological outcome, if any. Materials and Methods Records of consecutive patients admitted to the neurosurgical intensive care unit of the SCTIMST, Trivandrum between January 1999 and January 2011 with acute aneurysmal SAH were retrospectively analyzed. Results Of the 321 patients with SAH, 190 (59.2%) had abnormal ECGs. Repolarization abnormalities were the most common, with T wave inversion in the anterolateral leads occurring in 155 (48.3%) patients. By univariate analysis, female sex, Glasgow Coma Score (GCS) at admission of I, ST segment depression or T inversion in anterolateral leads, prolonged corrected QT interval, and sinus bradycardia were associated with increased risk of death. By multivariate analysis, only GCS and WFNS grade independently predicted mortality and none of the ECG changes predicted the same. Presence of tall T waves in anterior leads, T inversion in anterolateral leads, sinus bradycardia, and WFNS grade >1 were independently associated with GCS <15 and poor outcome at discharge. Conclusions In patients with acute aneurysmal SAH, repolarization abnormalities are the commonest ECG alterations. ECG alterations do not independently predict death, but independently predict poor discharge neurological status

Acute outcome of treating patients admitted with electrical storm in a tertiary care centre

AbstractBackgroundElectrical storm (ES) is a life threatening emergency. There is little data available regarding acute outcome of ES.AimsThe study aimed to analyze the acute outcome of ES, various treatment modalities used, and the factors associated with mortality.MethodsThis is a retrospective observational study involving patients admitted with ES at our centre between 1/1/2007 and 31/12/2013.Results41 patients (mean age 54.61 ± 12.41 years; 86.7% males; mean ejection fraction (EF) 44.51 ± 16.48%) underwent treatment for ES. Hypokalemia (14.63%) and acute coronary syndrome (ACS) (14.63%) were the commonest identifiable triggers. Only 9 (21.95%) patients already had an ICD implanted. Apart from antiarrhythmic drugs (100%), deep sedation (87.8%), mechanical ventilation (24.39%) and neuraxial modulation using left sympathetic cardiac denervation (21.95%) were the common treatment modalities used. Thirty-three (80.49%) patients could be discharged after a mean duration of 14.2 ± 2.31 days. Eight (19.5%) patients died in hospital. The mortality was significantly higher in those with EF < 35% compared to those with a higher EF (8 (42.11% vs 0 (0%), p = 0.03)). There was no significant difference in mortality between those with versus without a structural heart disease (8 (21.1% vs 0 (0%), p = 0.32)). Comparison of mortality an ACS with ES versus ES of other aetiologies (3 (50%) vs 5 (14.29) %, p = 0.076)) showed a trend towards significance.ConclusionWith comprehensive treatment, there is reasonable acute survival rate of ES. Hypokalemia and ACS are the commonest triggers of ES. Patients with low EF and ACS have higher mortality

Radial left ventricular dyssynchrony by speckle tracking in apical versus non apical right ventricular pacing- evidence of dyssynchrony on medium term follow up

Introduction: To study effects of various sites of right ventricular pacing lead implantation on left ventricular function by 2-dimensional (2D) speckle tracking for radial strain and LV dyssynchrony. Methods: This was retrospective prospective study. Fifteen patients each with right ventricular (RV) apical (RV apex and apical septum) and non-apical (mid septal and low right ventricular outflow tract [RVOT]) were programmed to obtain 100% ventricular pacing for evaluation by echo. Location and orientation of lead tip was noted and archived by fluoroscopy. Electrocardiography (ECG) was archived and 2D echo radial dyssynchrony was calculated. Results: The baseline data was similar between two groups. Intraventricular dyssynchrony was significantly more in apical location as compared to non-apical location (radial dyssynchrony: 108.2±50.2 vs. 50.5±24, P<0.001; septal to posterior wall delay [SLWD] 63.5±27.5 vs. 34±10.7, P<0.001, SPWD 112.5±58.1 vs. 62.7±12.1, P=0.003). The left ventricular ejection fraction was decreased more in apical location than non apical location. Interventricular dyssynchrony was more in apical group but was not statistically significant. The QRS duration, QTc and lead thresholds were higher in apical group but not statistically significant. Conclusion: Pacing in non apical location (RV mid septum or low RVOT) is associated with less dyssynchrony by specific measures like 2D radial strain and correlates with better ventricular function in long term