Programmed ventricular stimulation in structural heart disease: Implications of patterns of ventricular arrhythmias induced to long-term outcomes.

INTRODUCTION: Currently available data gives some credence to utility of VT induction studies in patients with stable ischemic cardiomyopathy, there are some unresolved questions as to define sensitive threshold for low-risk and the prognostic relevance of ill sustained or non-specific tachycardia on induction study. We evaluated potential ability of VT inducibility to predict likelihood of SHD (Structural heart disease) patients for subsequent arrhythmic or adverse cardiac events. MATERIAL AND METHODS: All consecutive patients with syncope/documented arrhythmia who had VT induction done were included and patients with VT storm, ACS,uncontrolled HF were excluded. We studied in 4 groups-monomorphic VT, sustained polymorphicVT, ill sustainedVT/VF and no VT/VF induced. The primary-endpoints were - Sudden death, all-cause mortality and secondary-endpoints were - MACE (AICD shock, death,HF, recurrence of VT). We screened 411 patients and included 169 within inducible (n = 79) and non-inducible group (n = 90). RESULTS: There were a higher number of patients with coronary artery disease, LV dysfunction, patients on amiodarone in inducible group and no difference in usage of beta-blockers. Recurrence of VT, composite of MACE was significantly higher in inducible group (p < 0.05). Mortality was not different in 3 groups compared with no VT/VF group. We found that monomorphic VT group had significantly higher MACE as compared to others and also predicted recurrence of VT and AICD shock and showed a trend towards significance for prediction of mortality. Inducible patients on AICD had mortality similar to non-inducible group. CONCLUSION: Induction of monomorphicVT/polymorphicVT with ≤3extrastimuli is associated with a higher number of MACE events on follow up. Induction of monomorphicVT predicts recurrence of VT/ICD shock.

Pediatric cardiology in India - In search of a holistic solution.

In response to the survey among early career pediatric cardiologists from India and the accompanying editorial, we invited comments and suggestions from thought leaders and senior functionaries in the field. We have summarized the thoughts and suggestions as a mini-symposium.

Flecainide challenge test: Predictors of unmasking of type 1 Brugada ECG pattern among those with non-type 1 Brugada ECG pattern.

BACKGROUND: Many subjects in community have non-type 1 Brugada pattern ECG with atypical symptoms, relevance of which is not clear. Provocative tests to unmask type 1 Brugada pattern in these patients would help in diagnosing Brugada Syndrome. However sensitivity and specificity of provocating drugs are variable. METHODS: We studied 29 patients referred to our institute with clinical presentation suggestive but not diagnostic of Brugada or with non-Type 1 Brugada pattern ECG. Flecainide Challenge Test (FCT) was done in these patients (IV Flecainide test in 4 patients and Oral Flecainide in 25 patients). Resting 12-lead ECG with standard precordial leads and ECG with precordial leads placed 1 Intercostal space above were performed after flecainide administration every 5 min for first 30 min and every 30 min thereafter until ECG became normal or upto 6 h. The positivity was defined as inducible Type 1 Brugada pattern in atleast 2 right sided leads. RESULT: Median age was 35(range = 5-65) years. In 16 (55%) patients the Type 1 Brugada pattern was unmasked. There were no episodes of major AV block, atrial or ventricular tachyarrhythmia. Three groups were considered for analysis: Group 1(n = 9) - FCT Positive among patients with non-type 1 Brugada ECG pattern, Group 2(n = 4) - FCT Negative among the patients with non-type 1 Brugada ECG pattern, and Group 3(n = 7) - FCT Positive among patients with no spontaneous Brugada ECG pattern. Binary logistic regression analysis found that family h/o SCD was predictive of FCT positivity in Group 1 (Odd's ratio 21, 95% Confidence interval 1.04 to 698.83, p = 0.004). CONCLUSION: Oral flecainide is useful and safe for unmasking of Type I Brugada pattern. In our study, among the many variables studied, family history of sudden cardiac death was the only predictor of flecainide test positivity among those with non-Type 1 Brugada pattern.

Acquired Fontan paradox in isolated right ventricular cardiomyopathy.

A 44-year-old woman presented with features of congestive heart failure. Echocardiography revealed severe right ventricular dysfunction along with passive minimally pulsatile pulmonary blood flow suggesting very high systemic venous pressures. This was confirmed with cardiac catheterization in which the pressures of superior vena cava and inferior vena cava (19 mmHg) were higher than the pulmonary artery pressures (17 mmHg). Elevation of systemic venous pressures above the pulmonary venous pressures, Fontan paradox, to drive the forward flow, is a specific feature of artificially created cavopulmonary shunts. Late stage of isolated right ventricular cardiomyopathy resulted in the spontaneous evolution of Fontan circulation with a nonfunctional right ventricle in this patient.

Enhanced P-selectin expression on platelet-a marker of platelet activation, in young patients with angiographically proven coronary artery disease.

P-selectin (CD62p) exposure is an established marker for platelet activation. P-selectin exposure can trigger variety of thrombotic and inflammatory reactions. In patients with coronary artery disease (CAD), platelets are activated, and hence, there is increased P-selectin exposure. The role of P-selectin exposure in patients on treatment with statins and anti-platelets is conflicting. A case-control study was performed to determine P-selectin exposure in consecutively recruited 142 patients (age ≤ 55 years) with angiographically proven CAD on treatment and 92 asymptomatic controls. P-selectin exposure was determined by flow cytometry. Data on conventional risk factors were obtained along with estimation of levels of thrombotic [fibrinogen, lipoprotein (a), tissue plasminogen activator, plasminogen activator inhibitor-1, homocysteine and von Willebrand factor] and anti-thrombotic factors (antithrombin III). The P-selectin exposure was compared among patient groups who had different modes of presentation of CAD and categories of CAD disease severity. The patients were followed up for a period of 26 months. The results indicate that P-selectin exposure was significantly elevated in patients (mean ± SD 9.24 ± 11.81) compared to controls (mean ± SD 1.48 ± 2.85) with p < 0.0001. Similarly, conventional risk factors were significantly elevated in patients. P-selectin exposure showed significant negative correlation with antithrombin III levels. P-selectin exposure was higher in patients who presented with acute coronary syndromes than those who presented with effort angina. Cardiovascular event rate was 6 % on follow-up. The study establishes that thrombotic-inflammatory pathways enhancing P-selectin exposure unrelated to treatment might be activated in patients, while the event rate remained lowered, and hence, treatment strategies should be inclusive to control these factors.

Circulating Thrombotic Risk Factors in Young Patients with Coronary Artery Disease Who Are on Statins and Anti-platelet Drugs.

Thrombotic risk factors may contribute to premature coronary artery disease (CAD), in addition to the conventional risk factors. There is paucity of data on studies evaluating the role of thrombotic factors in premature CAD in Indian patients. Thus a case-control study was performed to evaluate the role of thrombotic and atherogenic factors in young patients with angiographically proven CAD who are on treatment with statins and anti-platelet drugs. 152 patients (≤55 years) with angiographically proven CAD and 102 asymptomatic controls were recruited. Clinical and biochemical data were obtained in both groups. Blood levels of thrombotic factors-fibrinogen, antithrombin-III, tissue-plasminogen activator (t-PA), plasminogen activator inhibitor-1 (PAI-1), von-Willebrand factor (v-WF), lipoprotein(a) [Lp(a)] and homocysteine were analyzed. Patients had high levels of conventional CAD risk factors (diabetes mellitus, smoking, hypertension, dyslipidemia and positive family history) compared to controls. Logistic regression analysis revealed that low antithrombin-III (odds ratio/OR 11.2; 95 % confidence interval/CI 2.29-54.01), high fibrinogen (OR 6.04; 95 % CI 1.09-33.21) and high Lp(a) (OR 4.54; 95 % CI 0.92-22.56), as important, independent risk factors in patients. PAI-1(OR 0.15; 95 % CI 0.03-0.69) levels were significantly lower in patients. But other thrombotic risk factors studied (t-PA, v-WF and homocysteine) were comparable among patients and controls. The treatment using statins and anti-platelet drugs might be contributing to the control of some of the thrombotic risk factors. The strategies aiming at lowering the levels of thrombotic risk factors along with conventional risk factors may be useful in primary and secondary prevention of CAD.

A case of 'tachy-brady syndrome': What is the mechanism?

A young male presented with incessant narrow QRS tachycardia and left ventricular dysfunction. 24-Holter monitoring revealed multiple episodes of sustained and nonsustained episodes of tachycardia with prolonged sinus pauses at termination. The analysis of the electrocardiogram, followed by an invasive electrophysiological study, suggested an unusual mechanism for this tachy-brady syndrome.

Cervical origin of left subclavian artery: A rare anomaly.

A 22-year-old lady was referred to our institute for the management of pulmonary atresia with hypoplastic pulmonary arteries. Computed tomographic Angiography (CTA) showed right aortic arch with left brachicephalic artery as the first branch, which trifurcated into internal carotid, external carotid and subclavian artery high up in the neck at the level of third cervical vertebra. The left subclavian artery then travelled back caudally and entered into the arm after giving rise to a large collateral artery. This is the first ever-reported case of cervical origin of left subclavian artery (COLSA) in the literature. This anomaly can be explained by the absence of left fourth aortic arch with left subclavian artery arising from the left third aortic arch.

Early and 1-year outcome and predictors of adverse outcome following monocusp pulmonary valve reconstruction for patients with tetralogy of Fallot: A prospective observational study.

BACKGROUND AND OBJECTIVES: Repair of tetralogy of Fallot (TOF) with monocusp pulmonary valve reconstruction prevents pulmonary regurgitation (PR) for a variable period. Since postoperative outcome is governed by PR and right ventricular function, we sought to assess the severity of pulmonary regurgitation and right ventricular outflow (RVOT) gradient in the immediate postoperative period and at 1 year and attempted to identify the anatomical substrates responsible for adverse outcomes. METHODS: The study included 30 patients. Transthoracic echocardiography was performed before surgery, within 5 days of surgery, and 1 year later. Presence and severity of PR, RVOT gradient, and residual branch pulmonary stenosis were assessed. Right ventricular and monocusp valve functions were studied. RESULTS: Median age was 36.5 months (3-444 months). There were no deaths. Pulmonary regurgitation was mild in 18, moderate in 10, and severe in 2 patients immediately following surgery. At 1 year, 10 patients had severe PR and one had significant RVOT gradient. None of the variables like age, presence of supravalvar pulmonary branch stenosis, main pulmonary artery diameter, or mobility of monocusp valve was found to have any significant association with the progression of PR. McGoon index <1.5 showed a trend toward more PR, while patients with more residual RVOT gradient had lesser regurgitation. CONCLUSIONS: Repair of TOF with monocusp pulmonary valve reduces immediate postoperative PR. At 1 year, the monocusp valve underwent loss of function in a significant proportion and PR also progressed. This study could not identify any predictors of progression of PR, though patients with McGoon index <1.5 tended to have more PR while those with more outflow gradient had lesser PR.

A case of 'Masquerading' bundle branch block: a forgotten concept.

'Masquerading' bundle branch block (right bundle branch block in the precordial leads with left bundle branch block in frontal leads and left axis deviation) is seen most commonly with coronary artery disease and hypertension. No definite explanation is available so far for these changes. We are presenting a case of rare congenital intranuclear inclusion myopathy with congestive heart failure and 'Masquerading' bundle branch block in ECG.

An unusual cause for unruptured sinus of valsalva aneurysm.

Sinus of valsalva aneurysm is considered to be one of the rarest complications of inflammatory aortitis. Herewith, we are reporting a young male patient who presented to us with severe aortic regurgitation. On evaluation, he was found to have unruptured sinus of valsalva aneurysm. CT angiography and magnetic resonance imaging have shown value in the diagnosis of sinus of valsalva aneurysm.

Percutaneous closure of a moderate to large tubular or elongated patent ductus arteriosus in children younger than 3 years: is the ADO II appropriate?

Protrusion of the Amplatzer duct occluder (ADO) II device into the aortic isthmus or the pulmonary artery causing obstruction and residual flow has been reported, but the same has not been widely studied in small children with a patent ductus arteriosus (PDA) anatomy not considered suitable for closure with the ADO I device. This study aimed to report the safety and efficacy of the ADO II device in children younger than 3 years with a tubular or elongated PDA and to analyze the possible reasons for residual flow in children with such a PDA. In this study, 17 children younger than 3 years (mean age, 10.3 ± 7 months; mean weight, 6 ± 3.6 kg) underwent attempted closure of a tubular or elongated PDA (mean diameter at the narrowest point, 4.1 ± 1.1 mm) with the ADO II device between July 2010 and July 2012. Of the 17 patients, 16 (2 boys and 14 girls) completed the follow-up evaluation. A complete echocardiographic evaluation was performed on all the patients before PDA closure and at the follow-up visit, and the results were compared with those of previous published studies. Of the 16 patients, the 15 who completed the follow-up evaluation had successful device closure (1 device embolization). Residual flow was present in six patients immediately after deployment, which was reduced to three patients at the last follow-up visit. Five of nine patients closed with a 6-mm-long device had residual flow compared with only one of seven patients closed with a 4-mm-long device. After device closure, significant elevations of the left and right pulmonary artery velocities occurred in three and two patients, respectively; in 12 patients, descending thoracic aortic (DTA) velocities increased mildly. There was trend toward a fall in the elevated pressures at the last follow-up visit, although one patient had an elevation in right pulmonary artery velocity at last the follow-up echocardiogram compared with the echocardiogram immediately after closure. Hence, in children younger than 3 years with or without pulmonary arterial hypertension, closure of a PDA not amenable to closure with the ADO I device is feasible using the ADO II device, with an increased incidence of clinically nonsignificant complications. Selection of device dimensions according to the manufacturer's recommendation may not be the optimal strategy.

Differential diagnosis of vascular structures in relation to upper ascending aorta: The retro-aortic innominate vein.

The retroaortic course of left innominate vein is a rare entity which can be misinterpreted during echocardiography for other abnormal vascular structures under the arch of aorta. We report the case of a 2 month old infant where the suprasternal window showed 2 vascular structures beneath the aortic arch, one of which was traced to be a retroaortic innominate vein.

Regression of pulmonary vascular disease after therapy of Abernethy malformation in visceral heterotaxy.

A 1-year-old boy who had left isomerism and corrected transposition of the great arteries (c-TGA) with moderate-sized ventricular septal defect, severe pulmonary artery hypertension (PAH), and pulmonary vascular disease with significant right-to-left shunting received a diagnosis of type 2 Abernethy malformation, which was partly responsible for disproportionate PAH in the child. The malformation was treated by plugging of the portosystemic shunt. Follow-up cardiac catheterization on sildenafil demonstrated significant left-to-right shunting (2.16:1) and a fall in pulmonary vascular resistance, making surgical correction possible. This case highlights the importance of searching for additional rare causes of PAH in patients with congenital heart diseases when the degree of pulmonary hypertension is disproportional to the defect size.

Crisscross pulmonary artery with double aortic arch: an unusual association.

Anomalies of pulmonary artery origin are rare. Crisscross pulmonary artery origin is a rare benign anomaly characterized by the left pulmonary artery arising superiorly and to the right side of the right pulmonary artery. The condition is usually accompanied by a conotruncal anomaly. Here, we report a child with crisscross pulmonary arteries and a complete vascular ring formed by a double aortic arch, which was confirmed by computed tomography angiography. The child underwent surgical correction for relief of stridor.

An unusual mechanism of sustained right atrial tachycardia.

Lower loop re-entry (LLR) flutter is a rare type of atypical right atrial flutter. Most of the reported cases occurred in association with typical flutter patterns as a transient arrhythmia. Our case is unique in the fact the LLR was sustained and persisted independently.