Chronic total occulusion (CTO) has been identified as an independent predictor of ventricular arrhythmias in the VACTO Primary Study [Nombela-Franco L et al. Ventricular Arrhythmias Among Implantable Cardioverter Defibrillator Recipients for Primary Prevention: Impact of Chronic Total Coronary Occlusion (VACTO Primary Study). CIRCEP.111.968008 Published online before print December 28, 2011,
doi: 10.1161/?CIRCEP.111.968008]. They included all consecutive patients receiving implantable cardioverter defibrillators (ICD) for coronary artery disease and identified seventy one patients out of a total of one hundred and sixty two patients as having at least one chronic total occlusion. The presence of CTO was associated with higher rates of ventricular arrhythmia requiring ICD therapy and higher mortality with a log-rank <0.01. Chronic total occlusion was also independently associated with appropriate ICD intervention on multivariate analysis with a hazard ratio of 3.5 (p=0.003).
Chronic total occulusion (CTO) an independent predictor of ventricular arrhythmias
Myocardial strain and strain rate evaluation by tissue Doppler techniques
Deformation of the myocardium on application of a physical stress is termed myocardial strain. It is measured as the change in distance between two points (L) divided by the initial length (L0).
Myocardial strain: [L - L0)] / L0
Strain rate measured as the rate of deformation and the integral of strain rate over time give the strain. Strain rate has high resolution for evaluation of regional myocardial function and is an early indicator of regional myocardial dysfunction. In strain assessment, tissue Doppler technique is used to determine tissue velocities at two adjacent points along with the relative distance between the points. The instantaneous rate of change in the two velocities divided by the instantaneous distance between the two points is the strain rate. Positive values for strain rate indicate active myocardial contraction and negative strain rate indicates relaxation. Strain rate has a unit of sec-1 while strain is unitless. Strain and strain rate subtracts movement due to tethering effect of adjacent myocardium and hence represents the true regional function. Since they are deformation per unit length, they are also normalized for heart size and hence useful in children with different heart sizes.
Prediction of reversibility of constrictive pericarditis by magnetic resonance imaging
The usual treatment of constrictive pericarditis is pericardiectomy. But constriction can also be reversible in certain instances. Feng D and associates have conducted a pilot study to assess whether inflammatory markers and late gadolinium enhancement (LGE) of pericardium on cardiac magnetic resonance imaging can predict reversibility of constrictive pericarditis with anti inflammatory treatment [Cardiac Magnetic Resonance Imaging Pericardial Late Gadolinium Enhancement and Elevated Inflammatory Markers Can Predict the Reversibility of Constrictive Pericarditis After Antiinflammatory Medical Therapy. Circulation. 2011; 124: 1830-1837]. Almost half of their twenty nine patients with constrictive pericarditis had reversal with anti inflammatory treatment after a follow up of thirteen months. Baseline LGE pericardial thickness was more in those with reversible constriction. The intensity of pericardial LGE was moderate or severe in majority (93%) of the group with reversible constriction while it was only noted in one third of those with persistent constriction. Pericardial thickness of 3 mm or more on cardiac magnetic resonance imaging LGE had 86% sensitivity and 80% specificity for predicting reversible constriction. High levels of inflammatory markers like C-reactive protein and erythrocyte sedimentation rate were also noted in the the group with reversible constriction. Authors concluded that reversible constrictive pericarditis was associated with evidence of pericardial and systemic inflammation. These cases responded to anti inflammatory therapy with resolution of symptoms and constrictive physiology. The pericardial thickness assessed by LGE cardiac magnetic resonance imaging as well as pericardial and systemic inflammation were reduced with this therapy.
Late and very late stent thrombosis with drug eluting stents
Late and very late stent thrombosis with drug eluting stents still continue to be our concern. Fresh data from the jCypher registry is available from Kimura T and associates [Very Late Stent Thrombosis and Late Target Lesion Revascularization after Sirolimus-Eluting Stent Implantation: Five-year Outcome of the j-Cypher Registry. CIRCULATIONAHA.111.046599. Published online before print December 27, 2011, doi: 10.1161/?CIRCULATIONAHA.111.046599]. In this group of over twelve thousand and eight hundred patients undergoing sirolimus eluting stent implanation, the one month stent thrombosis was 0.3% while the one year cumulative stent thrombosis rate was 0.6%. Five year cumulative stent thrombosis rate was 1.6%. Acute coronary syndrome and proximal left anterior descending coronary artery were risk factors for early stent thrombosis. Side branch stenting, diabetes mellitus and end stage renal disease with or without hemodialysis were risk factors for late stent thrombosis. Current smoking and total stent length more than twenty eight millimeters were risk factors for very late stent thrombosis. Early stent thrombosis was calculated at thirty days, late stent thrombosis at one year and very late stent thrombosis at five years. Late and very late stent thrombosis rates were calculated at 0.26% per year. Target vessel revascularization (TLR) within first year was low at 7.35%. Beyond one year, it continued at a rate of 2.2% per year upto five years.
T-stenting and small protrusion (TAP stenting) in coronary bifurcations
T-stenting and small protrusion technique (TAP-Stenting) is used to enhance side branch ostial coverage. It is an intentional protrusion of side branch stent within the main branch during coronary bifurcation stenting which ensures side branch ostial coverage and facilitates final kissing balloon inflation [Burzotta et al Catheterization and Cardiovascular Interventions. 2007; 70:75–82]. This technique has been introduced because the conventional T-stenting method is associated with the risk of incomplete side branch ostial coverage, especially when the angle between the main branch and the side branch is acute. The position of the side branch stent is
adjusted to fully cover the proximal (or upper) part of the side branch ostium. This causes a small protrusion of side branch stent in the lower part of the ostium. This is leveled off by the final kissing inflation.
Association of congenital heart disease with developmental and psychiatric disorders
Morten Olsen and colleagues from the Department of Clinical Epidemiology, Aarhus University Hospital, Denmark report on the association of congenital heart disease with developmental and psychiatric disorders [Congenital Heart Defects and Developmental and Other Psychiatric Disorders - A Danish Nationwide Cohort Study. Circulation. 2011; 124: 1706-1712]. After evaluating around seven thousand congenital heart disease patients from a registry over a period from 1977 to 2002, they concluded that congenital heart disease patients are at increased risk of developmental and other psychiatric disorders. This is irrespective of whether they have undergone invasive therapeutic interventions or not. The hazard ratio for children with congenital heart disease with age less than fifteen years was 1.8 in boys and 2.5 in girls. The corresponding ratios were 1.6 and 1.0 in those aged between fifteen and thirty years.
Low atrial fibrillary rate predicts poor outcome in heart failure
Platonov PG and colleagues evaluated the role of atrial fibrillary rate in predicting the outcome in mild to moderate heart failure [Low Atrial Fibrillatory Rate Is Associated with Poor Outcome in Patients with Mild to Moderate Heart Failure. CIRCEP.111.964395 Published online before print January 10, 2012, doi: 10.1161/?CIRCEP.111.964395]. Atrial fibrillary rate is a measure of the atrial remodeling due to atrial fibrillation, which is both electrical and mechanical. The investigators analyzed high resolution twenty minute Holter electrocardiograms from one hundred and sixty nine patients with congestive heart failure. Estimation of atrial fibrillary rate was done using spatiotemporal QRST cancellation and time frequency analysis. Mean follow up period was forty four months and total mortality was the primary end point. Sudden death and heart failure death were secondary end points. Authors concluded that a reduced atrial fibrillary rate was associated with higher risk of death due to the progression of heart failure and could be a predictor of poor outcome.
Lutembacher syndrome: combination of atrial septal defect with mitral stenosis
The original description of Lutembacher syndrome was as a combination of atrial septal defect with mitral stenosis [Lutembacher R. De la sténose mitrale avec communication interauriculaire. Archives des maladies du coeur et des vaisseaux, Paris, 1916, 9: 237-260]. Though Lutembacher thought that both atrial septal defect and mitral stenosis were congenital, it is likely that in that sixty one year old lady, the atrial septal defect was congenital and mitral stenosis of rheumatic etiology. Later on several authors called a combination of atrial septal defect with any mitral valve lesion (stenosis, regurgitation or a combination) as Lutembacher syndrome. Some expanded it to include any left to right shunt at the atrial level. Recently even atrial level shunts created by septal puncture for balloon mitral valvotomy has been included in the spectrum of Lutembacher syndrome. Personally I would prefer to restrict the terminology to a combination of congenital atrial septal defect and rheumatic mitral stenosis as would have been the etiology of the original Lutembacher’s case. Presence of the two lesions have significant hemodynamic effects on the other lesion. The large unrestrictive atrial septal defect lowers the left atrial pressure and gradient across the mitral valve so that findings of mitral stenosis may be obscured and so will be the features of pulmonary venous congestion. In the presence of a large atrial septal defect, even a small gradient across the mitral valve is to be taken as significant. The obstruction to the left ventricular inflow on the other hand enhances the left to right shunt across interatrial septum so that torrential left to right shunts are likely in Lutembacher syndrome. This manifests as prominent right ventricular outflow murmur with a thrill. Cardiomegaly is also common. George Joseph and associates from Christian Medical College Hospital, Vellore, India has described complete percutaneous management of Lutembacher syndrome [Definitive percutaneous treatment of Lutembacher's syndrome. Catheter Cardiovasc Interv. 1999;48:199-204]. They closed the atrial septal defect with an Amplatzer septal occluder and dilated the stenotic mitral valve with Joseph balloon mitral valvotomy catheter (JOMIVA balloon).
Lower very late stent thrombosis with everolimus eluting stents (EES)
Though drug eluting stents have a much lower incidence of restenosis after percutaneous coronary intervention, late stent thrombosis and very late stent thrombosis occurring beyond one year after stent implantation are of great concern. This is especially when the individual needs withdrawal of dual antiplatelet therapy for a surgical procedure. A recent study by Raber L and colleagues have given some relief in that everolimus eluting stents have been shown superior to serolimus eluting stents and paclitaxel eluting stent [Very Late Coronary Stent Thrombosis of a Newer-Generation Everolimus-Eluting Stent Compared With Early-Generation Drug-Eluting Stents. A Prospective Cohort Study. Circulation. 2012; 125: 1110-1121]. They evaluated a cohort of over twelve thousand patients with unrestricted use of drug eluting stents of which over three thousand and eight hundred had serolimus eluting stents, over four thousand three hundred had paclitaxel eluting stents and over four thousand and two hundred had everolimus eluting stents implanted. The overal rate of thrombosis over the follow which ranged up to four years was 1.4 per hundred person-years for everolimus eluting stents. The figure was 2.9 for serolimus eluting stents and 4.4 for paclitaxel eluting stents (p<0.0001). The rates of early and late stent thrombosis were also similarly lower. There was also a lower risk of death or myocardial infarction with everolimus eluting stents when compared to paclitaxel eluting stents (p<0.0001) which was directly related to the stent thrombosis associated events.
Atrial tachycardia a step toward sinus rhythm after AF ablation?
Is the occurrence of atrial tachycardia a step towards sinus rhythm, after ablation of persistent atrial fibrillation (AF)? The results of the study by Ammar S et al [Arrhythmia Type After Persistent Atrial Fibrillation Ablation Predicts Success of the Repeat Procedure. Circulation: Arrhythmia and Electrophysiology. 2011; 4: 609-614] seems to point in that direction. They evaluated about eighty patients who underwent one or more repeat ablation for persistent atrial fibrillation. The initial ablation was pulmonary vein isolation with an extra substrate modification in the form of ablation of complex fractionated electrograms or linear ablations. Reablation was either for persistent atrial tachycardia, persistent AF or paroxysmal AF. The primary end point of the study was taken as freedom from any arrhythmia, off anti arrhythmic medications, for a period of six to nine months after the repeat ablation. It was found that those who presented with atrial tachycardia had a significantly better outcome than those who had a recurrence of persistent atrial fibrillation. Thus the authors concluded that the occurrence of atrial tachycardia after ablation for persistent atrial fibrillation may be considered as a step in the right direction – towards sinus rhythm.