An uncommon ECG manifestation of normal pacemaker function.

A presumed abnormal electrocardiogram (ECG) was obtained from an asymptomatic patient with a pacemaker. Systematic evaluation of the ECG revealed that the artifact was due to a physiological sensor in the pacemaker which was displayed when the enhanced pacemaker detection features on the ECG machine was activated. The article discusses the possible causes and an approach to similar artifacts.

Functional cardiac paraganglioma associated with a rare SDHC mutation.

Paragangliomas are catecholamine-secreting tumors external to the adrenal glands, most commonly arising in the head and neck, followed by the abdominal and thoracic cavities. The heart is a rare location for paragangliomas to originate from, with fewer than 50 cases as described in the literature. Functional paragangliomas of the right atrium are even more unusual, with only five cases reported to date. The investigations and therapies of a 41-year-old male presenting with a clinically functional cardiac paraganglioma are discussed. We performed a detailed pathology review of the primary cardiac tumor and a lung nodule to examine morphologic changes, along with an immunohistochemical profile (chromogranin A, tyrosine hydroxylase, MIB-1, and succinate dehydrogenase subunit B (SDHB)) of both tumors. Genetic testing of germline mutations in SDH genes was also completed. Both the 9.5-cm cardiac mass and 0.5-cm lung nodule were positive for chromogranin A and tyrosine hydroxylase and showed a global loss of SDHB expression. The MIB-1 labeling index of the smaller lesion and the bulk of the larger lesion was <5 %, but there were cellular foci of the larger lesion that had a labeling index of 10%. Genetic testing yielded an intronic frameshift mutation in the SDHC gene, c.IVS 5 + 1, G > A. We report the first case of a functional cardiac paraganglioma associated with an intronic frameshift SDHC gene mutation.

An unusual cause of stroke--the importance of saline contrast echocardiography.

We report a case of a 38-year-old man who presented with a cryptogenic stroke in whom a persistent left superior vena cava (PLSVC) to the left atrium was established as an isolated anomaly by both echocardiography and magnetic resonance angiography. This rare cardiac abnormality creates a systemic right to left shunt and the potential for cerebral abscess or infarction. Echocardiographic diagnosis may be missed unless intravenous saline contrast is performed using a left upper extremity vein.

Socioeconomic status and mortality after acute myocardial infarction.

BACKGROUND: Gradients that link socioeconomic status and cardiovascular mortality have been observed in many populations, including those of countries that provide publicly funded comprehensive medical coverage. The intermediary causes of such gradients remain poorly elucidated. OBJECTIVE: To examine the relationships among socioeconomic status, other health factors, and 2-year mortality rates after acute myocardial infarction (MI). DESIGN: Prospective cohort study. SETTING: Ontario, Canada. PATIENTS: 3407 patients who were hospitalized for acute MI in 53 large-volume hospitals in Canada from December 1999 to February 2003. MEASUREMENTS: The authors obtained self-reported measures of income and education and developed profiles of the patients' prehospitalization cardiac risks and comorbid conditions. To create these profiles, the authors used the patients' self-reports and retrospectively linked no less than 12 years' worth of previous hospitalization data. Mortality rates 2 years after acute MI were examined with and without sequential risk adjustment for age, sex, ethnicity, social support, cardiovascular history and risk, comorbid conditions, and selected in-hospital process factors. RESULTS: Income was strongly and inversely correlated with 2-year mortality rate (crude hazard ratio for high-income vs. low-income tertile, 0.45 [95% CI, 0.35 to 0.57]; P < 0.001). However, after adjustment for age and preexisting cardiovascular events or conventional vascular risk factors, the effect of income was greatly attenuated (adjusted hazard ratio for high-income vs. low-income tertile, 0.77 [CI, 0.54 to 1.10]; P = 0.150). Noncardiovascular comorbid conditions and in-hospital process factors had negligible explanatory effect. LIMITATIONS: Previous cardiovascular risks were ascertained through self-report or retrospectively through the longitudinal tracking of the hospitals' administrative databases. The study began with a cohort of patients who had an index cardiac event rather than with asymptomatic individuals. CONCLUSIONS: Age, past cardiovascular events, and current vascular risk factors accounted for most of the income-mortality gradient after acute MI. This observation suggests that the "wealth-health gradient" in cardiovascular mortality may be partially ameliorated by more rigorous management of known risk factors among less affluent persons. *For a list of members of the SESAMI Study Group, see the Appendix.

Determinants of incomplete left ventricular mass regression following aortic valve replacement for aortic stenosis.

OBJECTIVE: Incomplete regression of left ventricular hypertrophy (Abn-LVMI) following AVR for aortic stenosis (AS) may decrease long-term survival. In this prospective study, we identified the predictors of Abn-LVMI. METHODS: Between 1990 and 2000, 529 patients undergoing AVR for AS had clinical and hemodynamic data collected prospectively. Preoperative and annual postoperative transthoracic echos were employed to assess left ventricular mass index (LVMI) and hemodynamics. Abn-LVMI was defined as the 75th percentile of the lowest postoperative LVMI (>128 mg/m2, n = 133). All other patients were included in the normal regression group (N-LVMI). Univariate and multivariable logistic regression analyses were used to determine the predictors of Abn-LVMI. RESULTS: Preoperative hypertension, diabetes, coronary disease, valve size, mean postoperative gradients, effective orifice area, and patient-prosthesis mismatch (PPM, indexed EOA <0.60 cm2/m2) did not predict Abn-LVMI. By logistic regression the most important positive predictor of Abn-LVMI was the extent of preoperative LVMI, with an odds ratio of 37.5 (p < 0.0001). Survival (93.4 +/- 1.8% vs 94.8 +/- 2.3%, p = 0.90) and freedom from NYHA III-IV (75.0 +/- 3.7% vs 76.6 +/- 5.3%, p = 0.60) were similar for both groups at 7 years. CONCLUSIONS: Measures of valve hemodynamics were not important predictors of incomplete regression of hypertrophy. The extent of preoperative hypertrophy was the most important predictor, suggesting that earlier surgical intervention may reduce the extent of hypertrophy postoperatively. Furthermore, the significance of LV hypertrophy to long-term survival must be reassessed, in the absence of scientific evidence.

A formal [3 + 3] cycloaddition reaction. Improved reactivity using alpha,beta-unsaturated iminium salts and evidence for reversibility of 6pi-electron electrocyclic ring closure of 1-oxatrienes.

A detailed account regarding a formal [3 + 3] cycloaddition method using 4-hydroxy-2-pyrones and 1,3-diketones is described here. This formal cycloaddition reaction or annulation reaction is synthetically useful for constructing 2H-pyranyl heterocycles. The usage of alpha,beta-unsaturated iminium salts is significant in controlling competing reaction pathways to give exclusively 2H-pyrans. Most significantly, experimental evidence is provided to support the mechanism of this reaction that involves a sequential Knoevenagel condensation and a reversible 6pi-electron electrocyclic ring-closure of 1-oxatrienes.

Patient prosthesis mismatch is rare after aortic valve replacement: valve size may be irrelevant.

BACKGROUND: Although small valve size and patient-prosthesis mismatch are both considered to decrease long-term survival, little direct evidence exists to support this hypothesis. METHODS: To assess the prevalence of patient-prosthesis mismatch and the influence of small valve size on survival, we prospectively studied 1,129 consecutive patients undergoing aortic valve replacement between 1990 and 2000. Mean and peak gradients and indexed effective orifice area were measured by transthoracic echocardiography postoperatively (3 months to 10 years). Abnormal postoperative gradients were defined as those patients with mean or peak gradient above the 90th percentile (mean gradient > or = 21 or peak gradient > or = 38 mm Hg). Patient-prosthesis mismatch was defined as those patients with indexed effective orifice area below the 10th percentile (< 0.60 cm2/m2). RESULTS: A multivariable analysis identified internal diameter of the implanted valve as the only independent predictor of abnormal gradients postoperatively. However, there was no significant difference in actuarial survival between normal and abnormal gradient groups (7 years: 91.2% +/- 1.5% versus 95.0% +/- 2.2%; p = 0.48). Freedom from New York Heart Association class III or IV (7 years: 74.5% +/- 3.1% versus 74.6% +/- 6.2%; p = 0.66) and left ventricular mass index were not different between normal and abnormal gradient groups. Patients with and without patient-prosthesis mismatch were similar with respect to postoperative left ventricular mass index, 7-year survival (95.1% +/- 1.3% versus 94.7% +/- 3.0%; p = 0.54), and 7-year freedom from New York Heart Association class III or IV (79.3% +/- 6.6% versus 74.5% +/- 2.5%; p = 0.40). In patients with patient-prosthesis mismatch and abnormal gradients, the majority had prosthesis dysfunction owing to degeneration. CONCLUSIONS: Severe patient-prosthesis mismatch is rare after aortic valve replacement. Patient-prosthesis mismatch, abnormal gradient, and the size of valve implanted do not influence left ventricular mass index or intermediate-term survival.

Are stentless valves hemodynamically superior to stented valves? A prospective randomized trial.

BACKGROUND: Although stentless aortic bioprostheses are believed to offer improved outcomes, hemodynamic benefits remain unsubstantiated. METHODS: Fifty-three patients were randomized to receive the stented C-E pericardial valve (CE) and 46 patients the Toronto Stentless Porcine valve (SPV). Annuli were sized for the optimal insertion of both valve types, such that surgeons were required to commit to specific valve sizes before randomization. Echocardiographic measurements and functional status (Duke Activity Status Index) were assessed at 3 and 12 months postoperatively. RESULTS: Although cardiopulmonary bypass times (CE: 118.6+/-36.3 minutes; SPV: 148.5+/-30.9 minutes; p = 0.0001) and aortic cross-clamp times (CE: 95.4+/-28.6 minutes; SPV: 123.6+/-24.1 minutes; p = 0.0001) were significantly prolonged in the SPV group, perioperative morbidity and mortality was similar between groups. Neither valve offered a superior internal diameter for any given annular diameter (mean decrease in left ventricular outflow tract diameter after valvular implantation: SPV: 3.4+/-1.11 mm versus CE: 3.7+/-1.33 mm; p = 0.25). Although labeled mean valve size was significantly larger in the SPV group, the actual mean valve size based on internal valvular diameter was no different between groups (CE: 21.9+/-2.0 mm; SPV: 22.3+/-2.0 mm; p = 0.286). Although effective orifice areas increased, and mean and peak transvalvular gradients decreased in both groups over time, no differences were demonstrated between groups at 12 months. Similarly, although significant regression of left ventricular mass was accomplished in both groups over time, no differences were demonstrated between groups. Finally, Duke Activity Status Index scores of functional status improved in both groups over time; however, no differences were noted between groups at 12 months postoperatively. CONCLUSIONS: Although offering excellent outcomes, stentless valves did not demonstrate superior hemodynamic indices in comparison to stented valves up to 12 months after implantation.