Using the Appropriate Formula for QT Measurement Can Save Lives.

CDK 4/6 inhibitors, in combination with endocrine therapy, are the standard of care for patients with endocrinesensitive advanced breast cancer. This class of drug, however, is associated with QT prolongation, which serves as a surrogate marker for Torsades de Pointes (TdP), a cause of life-threatening ventricular arrhythmias and sudden cardiac death. The ICH E14 guidance document uses the Bazett formula for reporting of cardio-dynamic and safety ECG data in clinical trials. While there is substantial familiarity with the Bazett (QTcB) formula (QT/(RR) 1/2), the Fridericia (QTcF) formula (QT/(RR) 1/3 ) is preferred in the cancer population as it is often more accurate at heart rate extreme. Accordingly, the Fridericia formula is currently the standard adopted by the FDA when submitting QT data for review. At the King Faisal Specialist Hospital and Research Center, a total of 82 patients with advanced breast cancer, had a baseline ECG on day 1 before the initiation of ribociclib based therapy. Of the enrolled 82 patients, 19 (23%) were initially excluded from receiving ribociclib based due to a prolonged QTc >450ms, however, when the QTc-interval was manually measured and recalculated using Fridericia and Framingham formulae using MDCalC (https://www.mdcalc.com),17 of 19 patients successfully received their treatment without any arrhythmogenic effects. Repeat ECG on day14, and day 1 of cycle 2 demonstrated that none of these patients had QTc exceeding 480 ms. Our data highlights the complexities of evaluating the QT interval in oncology patients and the utility of the Fridericia/Framingham formulae in this population. Given these findings, we recommend the adoption of the Fridericia or Framingham formulae for measurement of QTc in all cancer patients exposed to potentially QT-prolonging cancer therapy.

Constrictive pericarditis following heart transplantation: Reality or fiction?

Constrictive pericarditis (CP) is a curable cause of diastolic heart failure with prior cardiac surgery being a recognizable etiology. We report a patient who developed CP one year following heart transplantation. Several clinical and imaging related factors may lead to diagnostic delays in similar patients, including the mistaken belief that transplanted hearts are devoid of pericardium and thus do not develop constriction. Post-transplantation pericardial effusion, mediastinitis, and cardiac rejection predispose to future CP. Caretakers should consider this entity in allograft recipients who develop heart failure symptoms of unclear etiology.

Ventricular tachycardia: beginning and ending fate of a benign invasive cardiac lipoma.

Cardiac lipomas are rare benign heart tumors. Their clinical manifestations primarily depend on their dimension and location. We describe a case of a 14-year-old boy complaining of palpitations. ECG showed non-sustained ventricular tachycardia (NSVT). Echocardiography and cardiac MRI showed a large apical mass suggestive of a cardiac lipoma. The patient underwent open-heart surgery which detected a pericardial mass, partially attached to the myocardium, and crossed by the distal segment of LAD. This critical anatomical relationship prevents its complete resection. The biopsy confirmed mature fat tissue. Postoperatively, Propranolol was started for NSVT episodes. After 8 months, he presented with VT recurrence. A subcutaneous ICD (S-ICD) was implanted. Two months later, he was admitted for an electrical storm with six appropriate shocks. Since then, amiodarone was added. Lipomas are not always benign and their surgery might be very difficult and unhelpful. A multidisciplinary team is crucial for their diagnosis and management.

Echocardiography is useful to predict postoperative atrial fibrillation in patients undergoing isolated coronary bypass surgery: A prospective study.

OBJECTIVE:: Postoperative atrial fibrillation is a major complication following coronary artery bypass graft. We hypothesized that, beyond clinical and electrocardiogram (ECG) data, transthoracic echocardiography could improve the prediction of postoperative atrial fibrillation. METHODS:: We prospectively studied 169 patients in sinus rhythm who underwent isolated coronary artery bypass graft in our institution. Clinical, biological, ECG and transthoracic echocardiography data were collected within 24 h before surgery. The patients were continuously monitored during the first five days, and then had daily 12-lead ECG afterwards until discharge. Postoperative atrial fibrillation was defined by any episode >10 min. RESULTS:: Postoperative atrial fibrillation was found in 65 patients (38%). Compared with those without, patients with postoperative atrial fibrillation were significantly older ( p=0.008), had more frequently a history of hypertension ( p=0.009), history of atrial fibrillation ( p<0.001) and New York Heart Association class ⩾III ( p=0.004). They also had longer PR interval ( p=0.005), higher preoperative NT-pro brain natriuretic peptide level ( p=0.006), left ventricle end-diastolic volume ( p=0.002), indexed left ventricle mass ( p<0.0001), indexed maximal left atrial volume ( p<0.0001), maximal right atrial area ( p<0.001) and lower left ventricle ejection fraction ( p=0.04). In multivariate analysis, history of atrial fibrillation (odds ratio =6.1, 95% confidence interval: 1.4-26.0, p=0.02) and indexed maximal left atrial volume (odds ratio =1.13, 95% confidence interval: 1.1-1.2, p=0.001) were the only two independent predictive factors of postoperative atrial fibrillation. The addition of echocardiographic parameters improved the predictive value (χ2) of the model, from 34 to 57. CONCLUSION:: A history of atrial fibrillation and indexed left atrial maximal volume are the best predictors of the occurrence of postoperative atrial fibrillation following coronary artery bypass graft. The identification of high risk population of postoperative atrial fibrillation using these two factors could lead to the development of targeted strategies to limit this frequent complication in these patients.

Prevalence and long-term outcome of aortic prosthesis-patient mismatch in patients with paradoxical low-flow severe aortic stenosis.

BACKGROUND: Patients with severe aortic stenosis (AS) and paradoxical low flow (PLF) have worse outcome compared with those with normal flow. Furthermore, prosthesis-patient mismatch (PPM) after aortic valve replacement is a predictor of reduced survival. However, the prevalence and prognostic impact of PPM in patients with PLF-AS are unknown. We aimed to analyze the prevalence and long-term survival of PPM in patients with PLF-AS. METHODS AND RESULTS: Between 2000 and 2010, 677 patients with severe AS, preserved left ventricular ejection fraction, and aortic valve replacement were included (74±8 years; 42% women; aortic valve area, 0.69±0.16 cm(2)). A PLF (indexed stroke volume ≤35 mL/m(2)) was found in 26%, and after aortic valve replacement, 54% of patients had PPM, defined as an indexed effective orifice area ≤0.85 cm(2)/m(2). The combined presence of PLF and PPM was found in 15%. Compared with patients with noPLF/noPPM, those with PLF/PPM were significantly older, with more comorbidities. They also received smaller and biological bioprosthesis more often (all P<0.01). Although early mortality was not significantly different between groups, the 10-year survival rate was significantly reduced in case of PLF/PPM compared with noPLF/noPPM (38±9% versus 70±5%; P=0.002), even after multivariable adjustment (hazard ratio, 2.58; 95% confidence interval, 1.5-4.45; P=0.0007). CONCLUSIONS: In this large catheterization-based study, the coexistence of PLF-AS before surgery and PPM after surgery is associated with the poorest outcome.

Cardiac amyloidosis: updates in diagnosis and management.

Amyloidosis is a severe systemic disease. Cardiac involvement may occur in the three main types of amyloidosis (acquired monoclonal light-chain, hereditary transthyretin and senile amyloidosis) and has a major impact on prognosis. Imaging the heart to characterize and detect early cardiac involvement is one of the major aims in the assessment of this disease. Electrocardiography and transthoracic echocardiography are important diagnostic and prognostic tools in patients with cardiac involvement. Cardiac magnetic resonance imaging better characterizes myocardial involvement, functional abnormalities and amyloid deposition due to its high spatial resolution. Nuclear imaging has a role in the diagnosis of transthyretin amyloid cardiomyopathy. Cardiac biomarkers are now used for risk stratification and staging of patients with light-chain systemic amyloidosis. Different types of cardiac complications may occur, including diastolic followed by systolic heart failure, atrial and/or ventricular arrhythmias, conduction disturbances, embolic events and sometimes sudden death. Senile amyloid and hereditary transthyretin amyloid cardiomyopathy have better prognoses than light-chain amyloidosis. Cardiac treatment of heart failure is usually ineffective and is often poorly tolerated because of its hypotensive and bradycardiac effects. The three main types of amyloid disease, despite their similar cardiac appearance, have specific new aetiological treatments that may change the prognosis of this disease. Cardiologists should be aware of this disease to allow early treatment.

Outcome and impact of surgery in paradoxical low-flow, low-gradient severe aortic stenosis and preserved left ventricular ejection fraction: a cardiac catheterization study.

BACKGROUND: The clinical relevance and management of paradoxical low-flow, low-gradient aortic stenosis (LFLG-AS) with preserved left ventricular ejection fraction remain debated. The aim of this study is to determine the features and outcome of LFLG-AS assessed using cardiac catheterization. METHODS AND RESULTS: Between 2000 and 2010, 768 patients with preserved left ventricular ejection fraction (>50%) and severe AS (valve area ≤ 1 cm(2)) without other valvular disease underwent cardiac catheterization. Mean age was 74 ± 8 years, 42% were women, and 46% had associated coronary artery disease. The prevalence of LFLG (indexed left ventricular stroke volume <35 mL/m(2) and mean gradient <40 mm Hg), normal flow high gradient, normal flow low gradient, and low flow high gradient were 13%, 50%, 22%, and 15%, respectively. Compared with patients with normal flow high gradient, those with LFLG were significantly older, with significantly reduced systemic arterial compliance and vascular resistances and increased valvulo-arterial impedance (all P<0.05). Ten-year survival was reduced in LFLG-AS (32 ± 9%) compared with normal flow high gradient (66 ± 4%; P=0.0002). After adjustment for other risk factors, LFLG-AS was independently associated with reduced long-term survival (hazard ratio, 1.85; 95% confidence interval, 1.08-3.07; P=0.02). However, despite higher operative mortality, patients with LFLG-AS undergoing aortic valve replacement seemed to have better long-term survival than those managed conservatively (5-year survival rate: 63 ± 6% versus 38 ± 15%; P=0.007; hazard ratio, 0.23; 95% confidence interval, 0.09-0.59; P=0.002). CONCLUSIONS: This large cardiac catheterization-based study reports that the LFLG-AS entity is not rare and is associated with worse outcome whether treated medically or surgically. However, these patients may have better long-term survival if treated surgically. Further prospective studies are needed to confirm this finding.

Left atrial size is an independent predictor of overall survival in patients with primary systemic amyloidosis.

BACKGROUND: Primary systemic amyloidosis is a severe plasma cell disorder characterized by the extracellular deposition of amyloid fibrils in different organs. Echocardiography is usually performed to assess cardiac involvement. We hypothesized that in patients with systemic amyloidosis, simple echocardiographic measurement of the left atrial (LA) diameter indexed to the body surface area might provide an important risk marker for this disease. METHODS: Between 1997 and 2011, 134 patients were diagnosed with primary systemic amyloidosis and had echocardiography within 28 days; we collected their baseline characteristics and biological and echocardiographic data retrospectively. LA enlargement was defined as recommended as M-mode LA diameter greater or equal to 23 mm/m(2). RESULTS: One hundred and eleven patients (83%) had echocardiographic LA dimension data available (mean age 63±11 years; 61% men; 31% previously diagnosed with systemic hypertension). Mean left ventricular ejection fraction (LVEF) and interventricular septum thickness (IVST) were 62±12% and 14±4 mm, respectively. Mean follow-up was 2.8±2.9 years (maximum 12 years). Patients with LA enlargement had a slightly lower LVEF (P=0.08) and a significantly greater IVST (P<0.0001). Overall, 5-year survival was 57±5%. However, 1-year and 5-year survival rates were markedly reduced in patients with LA enlargement versus those without LA enlargement (61±7% and 39±8% vs 83±5% and 72±7%, respectively; P=0.0007). On multivariable analysis, after adjusting for age, sex, LVEF, IVST, presence of hypertension and creatinine concentration, LA enlargement remained an independent predictor of overall mortality at 5 years (hazard ratio 2.47; 95% confidence interval 1.11-5.90; P=0.02). CONCLUSION: LA enlargement, a surrogate marker of diastolic dysfunction, is an independent predictor of long-term mortality and may therefore help to enhance risk stratification and management of patients presenting with amyloidosis.

A novel mutation in a large French-Canadian family with LGMD1B.

BACKGROUND: Limb girdle muscular dystrophy type 1B is an autosomal dominant disease characterized by late onset proximal muscle involvement associated with cardiac complications such as atrioventricular conduction blocks, dilated cardiomyopathy, and sudden death. OBJECTIVE: Define the full phenotypic spectrum of a new mutation in the LMNA gene causing limb girdle muscular dystrophy type 1B. METHODS: We identified a large French Canadian family with the LGMD 1B phenotype and a cardiac conduction disease phenotype that carried a new mutation in the LMNA gene and sought to define its full phenotypic spectrum by performing complete neurological and cardiac evaluations, muscle biopsy, RNA and DNA studies. RESULTS: The proband and 12 living at risk relatives were tested. In total, we identified seven carriers of a new (IVS9-3C > G) LMNA gene mutation. Of the three symptomatic patients, all had cardiac involvement, but only two presented proximal limb weakness. The one available muscle biopsy demonstrated a normally expressed lamin A/C protein, localized at the nuclear envelope. RNA study revealed a loss of exon 10 transcription caused by the IVS9-3C to G splicing mutation. CONCLUSIONS: We have identified a new mutations in the LMNA gene in a French-Canadian family. This diagnosis has important implications for affected patients and their siblings since they may eventually require pacemaker implantation.

Mechanisms, prevention, and treatment of atrial fibrillation after cardiac surgery.

Post-operative atrial fibrillation (POAF) is a frequent complication occurring in 30% to 50% of patients after cardiac surgery. It is associated with an increased risk of mortality and morbidity, predisposes patients to a higher risk of stroke, requires additional treatment, and increases the costs of the post-operative care. The aim of this review is to present the current state of knowledge about the risk factors, mechanisms, prevention, and treatment of this complication. In addition to the well known risk factors for the development of POAF such as age, left atrial enlargement, and valvular surgery, new metabolic risk factors related to visceral obesity have been identified. With regard to the prevention of POAF, beta-blocker drugs are effective and safe and can be used in most patients, whereas amiodarone can be added in high-risk patients. Biatrial pacing was shown to be effective; however, its complexity might limit its application. Although there are only few data regarding the usefulness of magnesium, statins, N-3 polyunsaturated fatty acids, and corticosteroids, their addition to beta-blocker drugs might be of benefit for further reducing POAF. Treatment includes the use of an AV nodal blocking agent to achieve the rate control. If AF does not spontaneously convert to sinus rhythm within 24 h, anticoagulation should be initiated and a rhythm control strategy should be attempted. More investigations are warranted to explore mechanisms by which POAF occurs. This new knowledge would undoubtedly translate into a more efficient prevention and treatment of this common post-operative complication that is associated with a major health and economic burden.

Life-threatening left atrial wall hematoma secondary to a pulmonary vein laceration: an unusual complication of catheter ablation for atrial fibrillation.

BACKGROUND: Several complications may occur during catheter ablation for atrial fibrillation (AF). We report an unusual case of left atrial wall hematoma without pericardial effusion secondary to a right inferior pulmonary vein (PV) laceration. The use of real-time transesophageal echocardiography (TEE) during the procedure can be useful for early detection of this potentially lethal complication. CASE REPORT: A 49-year-old woman was referred for AF ablation. Her past medical history included severe systemic lupus with chronic renal failure treated with immunosuppressive and steroid drugs. A TEE-guided hybrid approach for AF ablation was performed with circular PV lesions and antrum and ostial electrical isolation. While performing the mitral isthmus line, the TEE showed a growing hematoma at the posterior left atrial wall. Rapidly, left atrium (LA) collapse associated with hemodynamic compromise occurred without any pericardial effusion. The patient was brought to the operating room. No pericardial effusion was seen at the time of surgery. The cardiac exploration showed a right inferior PV laceration. The visual inspection of the LA revealed thin and friable tissue. The patient survived. After 25 months of follow-up, she is still free from symptomatic AF. CONCLUSIONS: Left atrial wall hematoma without pericardial effusion is a rare and life-threatening complication after catheter-based AF ablation. TEE is a valuable monitoring tool to accurately diagnose several acute complications and prompt rapid intervention.

Obesity and metabolic syndrome are independent risk factors for atrial fibrillation after coronary artery bypass graft surgery.

BACKGROUND: Postoperative atrial fibrillation (POAF) is a highly prevalent complication after cardiac surgery with substantial effects on outcomes. Previous studies have reported that obesity is a risk factor for POAF after cardiac surgery. However, it is unknown whether the metabolic syndrome (MS) also increases the risk of postoperative atrial fibrillation. METHODS AND RESULTS: We retrospectively analyzed the association between obesity and MS and the incidence of new-onset POAF in a total of 5085 patients who underwent isolated coronary artery bypass grafting surgery with no concomitant valvular surgery. Of these patients, 1468 (29%) were obese (body mass index > or = 30 kg/m2) and 2320 (46%) had a MS as defined by the NCEP-ATPIII. POAF occurred in 1374 (27%) of the patients. Obesity was associated (P<0.001) with increased incidence of POAF in the whole cohort as well as in patients > 50 years old but not in patients < or = 50 years old. In these patients, MS was the only metabolic factor to be significantly associated with higher incidence of POAF (12% versus 6%, P=0.01). In > 50-year-old patients, mild (30 < or = body mass index < 35 kg/m2) and moderate-severe (body mass index > or = 35 kg/m2) obesity were independently associated with a 1.4-fold (95% CI: 1.10 to 1.71; P=0.004) and 2.3-fold (95% CI: 1.71 to 3.13; P<0.0001) increase in the risk of POAF, respectively. In < or = 50-year-old patients, MS (relative risk [RR]: 2.36; 95% CI: 1.10 to 5.12; P=0.02) but not obesity was independently associated with POAF. CONCLUSIONS: This study demonstrates that obesity is a powerful risk factor for the occurrence of POAF after isolated coronary artery bypass grafting surgery in patients older than 50 years. However, in the younger population, this association is not observed and MS is the only metabolic risk factor to be independently associated with POAF.

Metabolic syndrome increases operative mortality in patients undergoing coronary artery bypass grafting surgery.

OBJECTIVES: The aim of this study was to determine the impact of the metabolic syndrome (MS) on operative mortality after a coronary artery bypass grafting surgery (CABG). BACKGROUND: Diabetes and obesity are highly prevalent among patients undergoing CABG. However, it remains unclear whether these factors have a significant impact on operative mortality after this procedure. We hypothesized that the metabolic abnormalities associated with MS could negatively influence the operative outcome of CABG surgery. METHODS: We retrospectively analyzed the data of 5,304 consecutive patients who underwent an isolated CABG procedure between 2000 and 2004. Of these 5,304 patients, 2,411 (46%) patients met the National Cholesterol Education Program-Adult Treatment Panel III criteria for MS. The primary end point was operative mortality. RESULTS: The operative mortality after CABG surgery was 2.4% in patients with MS and 0.9% in patients without MS (p < 0.0001). The MS was a strong independent predictor of operative mortality (relative risk 3.04 [95% confidence interval (CI) 1.73 to 5.32], p = 0.0001). After adjusting for other risk factors, the risk of mortality was increased 2.69-fold (95% CI 1.43 to 5.06; p = 0.002) in patients with MS and diabetes and 2.36-fold (95% CI 1.26 to 4.41; p = 0.007) in patients with MS and no diabetes, whereas it was not significantly increased in the patients with diabetes and no MS. CONCLUSIONS: This is the first study to report that MS is a highly prevalent and powerful risk factor for operative mortality in patients undergoing a CABG surgery. Thus, interventions that could contribute to reduce the prevalence of MS in patients with coronary artery disease or that could acutely modify the metabolic perturbations of MS at the time of CABG might substantially improve survival in these patients.