Shuchita Gupta

Tachycardia mediated cardiomyopathy: Pathophysiology, mechanisms, clinical features and management

Tachycardia mediated cardiomyopathy (TMC) is a reversible form of dilated cardiomyopathy that can occur with most supraventricular and ventricular arrhythmias. Despite the plethora of literature describing this entity in animal models, as well as humans, it remains poorly understood. Over the last decade, new etiologies of TMC, such as frequent premature ventricular complexes in normal hearts, have been identified. Recent advances in catheter-based ablation therapies, particularly for atrial fibrillation and ventricular arrhythmias, have added a new dimension to the treatment of this condition. This review describes the pathophysiology, proposed mechanisms, clinical features and management in various arrhythmic conditions.

Incidence of, predictors for, and mortality associated with malignant ventricular arrhythmias in non-ST elevation myocardial infarction patients.

BackgroundThe incidence of non-ST elevation myocardial infarction (NSTEMI) is increasing. Although life-threatening ventricular arrhythmias have been well-documented in patients with ST elevation MI (STEMI), their incidence and importance in NSTEMI have not been examined in similar detail. We examined the incidence, predictors, and mortality rates of ventricular arrhythmias in a cohort of NSTEMI patients undergoing an early invasive strategy. MethodsConsecutive patients admitted with NSTEMI who underwent cardiac catheterization within 48 h of admission were identified by chart review. Presence and type of ventricular arrhythmias and 30-day mortality were recorded. Malignant arrhythmias were defined as sustained ventricular tachycardia (VT, >100 beats/min lasting >30 s) or fibrillation (VF). Clinical risk factors, laboratory values, findings on electrocardiogram, echocardiogram, cardiac catheterization, and revascularization procedure data were recorded. ResultsVT/VF occurred in 21 (7.6%) of 277 NSTEMI patients. Sixty percent of these events occurred within the first 48 h after hospital admission, with a median occurrence at 72 h. Twelve patients (4.3%) required defibrillation. Troponin levels were higher and left ventricular ejection fraction was lower in the VT/VF group. Multivariable analysis also identified the presence of left bundle branch block and need for urgent coronary artery bypass grafting as significant predictors of malignant ventricular arrhythmias. Thirty-day mortality was significantly higher in NSTEMI patients with malignant ventricular arrhythmias than without (38 vs. 3%, P<0.001). ConclusionDespite an early invasive strategy, malignant ventricular arrhythmias are frequent in NSTEMI patients and are associated with increased 30-day mortality.

Radionuclide imaging of cardiac sympathetic innervation in heart failure: unlocking untapped potential

Heart failure (HF) is associated with sympathetic overactivity, which contributes to disease progression and arrhythmia development. Cardiac sympathetic innervation imaging can be performed using radiotracers that are taken up in the presynaptic nerve terminal of sympathetic nerves. The commonly used radiotracers are 123I-metaiodobenzylguanidine (123I-mIBG) for planar and single-photon emission computed tomography imaging, and 11C-hydroxyephedrine for positron emission tomography imaging. Sympathetic innervation imaging has been used in assessing prognosis, response to treatment, risk of ventricular arrhythmias and sudden death and prediction of response to cardiac resynchronization therapy in patients with HF. Other potential applications of these techniques are in patients with chemotherapy-induced cardiomyopathy, predicting myocardial recovery in patients with left ventricular assist devices, and assessing reinnervation following cardiac transplantation. There is a lack of standardization with respect to technique of 123I-mIBG imaging that needs to be overcome for the imaging modality to gain popularity in clinical practice.

Distribution of left ventricular ejection fraction in angina patients with severe coronary artery disease not amenable to revascularization.

BackgroundAs the number of angina patients with severe coronary artery disease not amenable to revascularization increases, new therapies will be developed. How patients with depressed compared to normal left ventricular ejection fraction (LVEF) will respond to new therapies may differ. HypothesisWe conducted a retrospective chart review to determine the distribution of LVEF in angina patients with severe coronary artery disease (three-vessel disease with >50% stenosis major epicardial vessels or >50% stenosis left main) not amenable to revascularization. MethodsPatients underwent cardiac catheterization between 2004 and 2009. LVEF, measured by echocardiography, nuclear-gated imaging or radioventriculography within 6 months of catheterization, was recorded. Demographics, symptoms, risk factors, past myocardial infarction, catheterization results, medications, and the Duke Coronary Artery Jeopardy Score were recorded. ResultsEight thousand six hundred and ninety-nine patient charts were reviewed; 124 met criteria. There was a continuous, and not bimodal, distribution of LVEF. Fifty-eight patients (47%) in the normal LVEF group were compared to 66 patients (53%) in the abnormal LVEF group (<50%). The two groups were statistically different only with respect to shortness of breath as a presenting symptom and diagnosis of congestive heart failure during index hospitalization. Follow-up mortality was high and did not differ between LVEF groups (35% vs. 34%). ConclusionThere is a wide distribution of LVEF among angina patients not amenable to revascularization. A novel finding of this study showed that mortality was high regardless of LVEF. As new therapies for angina are developed, attention will need to be paid to how such therapies affect these two patient groups.

Trends, etiologies, and predictors of 90-day readmission after percutaneous ventricular assist device implantation: A national population-based cohort study

Percutaneous ventricular assist devices (pVADs) are indicated to provide hemodynamic support in high‐risk percutaneous interventions and cardiogenic shock. However, there is a paucity of published data regarding the etiologies and predictors of 90‐day readmissions following pVAD use. We studied the data from the US Nationwide Readmissions Database (NRD) for the years 2013 and 2014. Patients with a primary discharge diagnosis of pVAD use were collected by searching the database for International Classification of Diseases, Ninth Revision, Clinical Modification (ICD‐9‐CM) procedural code 37.68 (Impella and TandemHeart devices). Amongst this group, we examined 90‐day readmission rates. Comorbidities as identified by “CM_” variables provided by the NRD were also extracted. The Charlson Comorbidity Index was calculated using appropriate ICD‐9‐CM codes, as a secondary diagnosis. A 2‐level hierarchical logistic regression model was then used to identify predictors of 90‐day readmission following pVAD use. Records from 7074 patients requiring pVAD support during hospitalization showed that 1562 (22%) patients were readmitted within 90 days. Acute decompensated heart failure (22.6%) and acute coronary syndromes (11.2%) were the most common etiologies and heart failure (odds ratio [OR]: 1.39, 95% confidence interval [CI]: 1.17–1.67), chronic obstructive pulmonary disease (OR: 1.26, 95% CI: 1.07–1.49), peripheral vascular disease (OR: 1.305, 95% CI: 1.09–1.56), and discharge into short‐ or long‐term facility (OR: 1.28, 95% CI: 1.08–1.51) were independently associated with an increased risk of 90‐day readmission following pVAD use. This study identifies important etiologies and predictors of short‐term readmission in this high‐risk patient group that can be used for risk stratification, optimizing discharge, and healthcare transition decisions.

High Right Ventricular Stroke Work Index Is Associated with Worse Kidney Function in Patients with Heart Failure with Preserved Ejection Fraction

Background: In patients with heart failure with preserved ejection fraction (HFpEF), worse kidney function is associated with worse overall cardiac mechanics. Right ventricular stroke work index (RVSWI) is a parameter of right ventricular function. The aim of our study was to determine the relationship between RVSWI and glomerular filtration rate (GFR) in patients with HFpEF. Method: This was a single-center cross-sectional study. HFpEF is defined as patients with documented heart failure with ejection fraction > 50% and pulmonary wedge pressure > 15 mm Hg from right heart catheterization. RVSWI (normal value 8–12 g/m/beat/m2) was calculated using the formula: RVSWI = 0.0136 × stroke volume index × (mean pulmonary artery pressure – mean right atrial pressure). Univariate and multivariate linear regression analysis was performed to study the correlation between RVSWI and GFR. Result: Ninety-one patients were included in the study. The patients were predominantly female (n = 64, 70%) and African American (n = 61, 67%). Mean age was 66 ± 12 years. Mean GFR was 59 ± 35 mL/min/1.73 m2. Mean RVSWI was 11 ± 6 g/m/beat/m2. Linear regression analysis showed that there was a significant independent inverse relationship between RVSWI and GFR (unstandardized coefficient = –1.3, p = 0.029). In the subgroup with combined post and precapillary pulmonary hypertension (Cpc-PH) the association remained significant (unstandardized coefficient = –1.74, 95% CI –3.37 to –0.11, p = 0.04). Conclusion: High right ventricular workload indicated by high RVSWI is associated with worse renal function in patients with Cpc-PH. Further prospective studies are needed to better understand this association.

Effect of Primary Percutaneous Coronary Intervention on Renal Function in Acute ST Elevation Myocardial Infarction

Effect of Primary Percutaneous Coronary Intervention on Renal Function in Acute ST Elevation Myocardial Infarction Objectives: Assess the effect of primary percutaneous coronary intervention (PCI) on renal function in the setting of acute ST elevation myocardial infarction (STEMI). Methods: Retrospective chart review of 270 STEMI patients that underwent primary PCI. Creatinine clearance was calculated using the re-expressed 4–variable Modification of Diet in Renal Disease (MDRD) formulas upon presentation to emergency room and prior to discharge from hospital or death. Results: Mean creatinine level upon presentation was 1.14 ± 0.43 mg/dl and upon discharge 1.07 ± 0.51 mg/dl (p=0.013). Mean CrCl on admission was 77 ± 27 ml/min/1.73m2 and improved to 86 ± 31 ml/min/1.73m2 upon discharge (p<0.001). This improvement was observed in patients with all stages of chronic kidney disease (CKD), including stage III (47 ± 9 vs 55 ± 18 ml/min/1.73m2, p=0.001) and stage IV (24 ± 4 vs 29 ± 10 ml/min/1.73m2; p=0.13). Statistically significant improvement in CrCl (79 ± 28 vs. 86 ± 31 ml/min/1.73m2, p < 0.001) was observed in African American patients (72% of study group). Conclusion: In STEMI patients, primary PCI does not appear to be associated with worsening, but rather an improvement, in renal function upon hospital discharge.

Electrocardiographic and echocardiographic changes in patients undergoing liver transplant stratified by outcomes

Background: Association between electrocardiographic (EKG) and echocardiographic (Echo) parameters and outcomes in cirrhotic cardiomyopathy are not clear. Methods: We studied 73 adult patients with liver cirrhosis referred for liver transplantation between January 2007 and December 2013 at a tertiary liver transplant center. A complete 12-lead EKG and Echo was done prior to and after liver transplant. Patients with history of coronary artery disease, pre-existing heart failure and valvular heart disease were excluded. Standard 2D echo and diastolic function parameters were studied. We excluded 10 patients with incomplete data. Results: Mean age was 55± 8yrs, 65% (41 of 63) were men and the mean EF (ejection fraction) was 61±8%. Prevalence of diastolic dysfunction (DD) was 57% (36 of 63), of which 25%(9 of 36) were Stage 1, 67%(24 of 36) were Stage 2 and 8%(3 of 36) were Stage 3, respectively. There were 22(30%) deaths in the follow up period (1132 ± 795 days). Among the survivors, the PR-interval, QRS duration, QTC interval and Left atrial volume index showed statistically significant improvement compared to the deceased subjects. There was a trend towards improvement in DD post-transplant. Mortality was 15% in subjects with improved diastolic function versus 34% with worsening diastolic function (p=0.1). Death was predominantly due to non-cardiac complications (table). Conclusions: Prevalence of DD in cirrhotic cardiomyopathy was 57% in our study. There was a significant improvement in EKG and Echo parameters post-transplant. However, it did not significantly improve outcomes as most of the deaths were due to non-cardiac complications. Incidence of post-transplant major complications ![][1] [1]: /embed/graphic-1.gif

Usefulness of the Echocardiographic Calcium Score to Refine Risk of Major Adverse Cardiovascular Events Beyond the Traditional Framingham Risk Score

Echocardiographic calcifications are associated with major adverse cardiovascular events (MACE). A recently described semiquantitative Global Cardiac Calcium Score (GCCS) has been associated with mortality and stroke, with increasing scores associated with increasing risk. This score assigns points for calcium in the aortic root and valve, mitral valve and annulus, and submitral apparatus, with additional points for restricted leaflet mobility. We tested the hypothesis that the GCCS could improve prediction of MACE beyond traditional risk scores. This was a retrospective study of 216 subjects from a general echocardiography database (mean age 59 ± 15; 51% male). Follow-up was 3.8 ± 1.7 years. The Framingham Risk Score (FRS) and Pooled Cohort Equations (PCE) were applied to each patient. Mean GCCS was 3.2 ± 2. In the total cohort, GCCS predicted MACE (myocardial infarction, stroke, all-cause mortality), even after adjusting for FRS (odd ratio 1.19, p = 0.03). There were 106 subjects (49%) in the low-risk FRS group, 71 (33%) in the intermediate-risk group, and 39 (18%) in the high-risk group. GCCS ≥3 was associated with increased MACE (vs <3) in the low-risk group (p = 0.03), while GCCS <3 was associated with decreased MACE (vs ≥3) in the high-risk group (p = 0.04). When applied to the PCE risk estimate (dichotomized at <7.5% vs ≥7.5%) the GCCS similarly refined risk prediction. In conclusion, the semiquantitative GCCS appears to be a marker of additional unaccounted risk factors; it is easily applied and can further stratify risk of MACE beyond traditional FRS or PCE estimates.