Clinical utility of central venous saturation for the calculation of cardiac index in cardiac patients.

BACKGROUND: Mixed venous saturation (MVS) obtained from the distal pulmonary artery (PA) during Swan-Ganz catheterization is the criterion standard for calculating cardiac output (CO) and cardiac index (CI) with the use of the Fick method. We think that calculating CI with the use of central venous saturation (CVS) instead of PA-MVS is both feasible and accurate. Earlier studies were small, enrolled heterogeneous patient populations, and resulted in inconsistent findings. METHODS: All patients undergoing right heart catheterization from January 2011 to January 2012 in our catheterization lab with simultaneous measurements of MVS obtained from the distal PA and CVS obtained from the superior vena cava (SVC) or right atrium (RA) were included. Out of the 902 patients enrolled, we excluded patients (n = 50) who had known cardiac shunt or dialysis fistula, had duplicate medical records, or were septic. We calculated the CI with the use of the assumed Fick method using both MVS (criterion standard) and CVS (SVC or RA saturations) in the remaining 852 patients. We measured the correlation and the agreement between the 2 methods with the use of the Pearson correlation coefficient and Bland-Altman analysis. RESULTS: Totals of 112 patients with simultaneous PA and RA saturation measurements (group I) and 740 patients with simultaneous PA and SVC saturation measurements (group II) were included. We found an excellent linear correlation between SVC and PA saturation (r = 0.928) and between RA and PA saturation (r = 0.95). There was also an excellent correlation between CI calculated with the use of PA saturation and CI calculated with the use of SVC (r = 0.87) or RA (r = 0.93) saturation. The mean bias of CVS-derived CI compared with MVS-derived CI (criterion standard) was -0.1 (95% limits of agreement [LOA] -1 to +0.77) in the SVC group and -0.006 (LOA -0.68 to +0.69) in the RA group. Patients with low CI had stronger correlation and smaller bias between the 2 methods compared with those with normal or high CI. The presence of baseline hypoxemia, valvular heart disease, or acute coronary syndrome had no significant effect on the correlation or the bias between the 2 methods. CONCLUSIONS: In cardiac patients, CVS can be used as a surrogate to true MVS in the calculation of CI. This method is readily available in patients who have central venous access, and may aid in early goal-directed treatment when cardiogenic shock is suspected.

Inpatient Outcomes for Myocarditis-Related Heart Failure.

Background Heart failure (HF) is one of the leading causes of hospitalizations among adults, accounting for high rates of morbidity and mortality in the United States. Myocarditis is a less common etiology of HF, and its outcomes are less well understood. Methods We used the Nationwide Readmissions Database from 2016 to 2019, extracting adult patients with a primary diagnosis of HF who were admitted between January and November of each year studied. We excluded patients with missing data on event time or length of stay. Inpatient outcomes were compared between cases of HF without myocarditis and myocarditis-associated HF (MAHF). Survey procedures were applied. Propensity scores as covariates were used in survey-weighted models to estimate the population average treatment effect on the treated using SAS 9.4. Results We included 4,454,272 HF-related weighted admissions for which 4,605 patients (0.1%) had a concurrent diagnosis of myocarditis. Overall, patients with MAHF, compared with HF without myocarditis, were younger (mean age: 53 years vs. 72 years, p < 0.001) with fewer women (45 vs. 48%), respectively. Patients with MAHF had more inpatient complications including cardiac arrest, cardiogenic shock, and use of mechanical circulatory support ( p < 0.001) despite having fewer comorbidities such as diabetes, hypertension, and renal disease. Patients with MAHF had longer mean lengths of stay (9.2 vs. 5.5 days, p < 0.001). In-hospital mortality during index admission was significantly higher in MAHF at 3.9% compared with 2.8% for HF without myocarditis ( p < 0.001). Myocarditis was a key predictor of inpatient mortality adjusting for risk factors. Conclusion Myocarditis-related HF is associated with increased inpatient mortality, resource utilization, and prolonged hospitalization.

Pacing for drug-refractory or drug-intolerant hypertrophic cardiomyopathy.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is a genetic disease with an autosomal-dominant inheritance for which negative inotropes are the most widely used initial therapies. Observational studies and small randomised trials have suggested symptomatic and functional benefits using pacing and several theories have been put forward to explain why. Pacing, although not the primary treatment for HCM, could be beneficial to patients with relative or absolute contraindications to surgery or alcohol ablation. Several randomised controlled trials comparing pacing to other therapeutic modalities have been conducted but no Cochrane-style systematic review has been done. OBJECTIVES: To assess the effects of pacing in drug-refractory or drug-intolerant hypertrophic cardiomyopathy patients. SEARCH METHODS: We searched the following on the 14/4/2010: CENTRAL (The Cochrane Library 2010, Issue 1), MEDLINE OVID (from 1950 onwards ), EMBASE OVID (from 1980 onwards ), Web of Science with Conference Proceedings (from 1970 onwards). No language restrictions were applied. SELECTION CRITERIA: Randomised controlled trials of either parallel or crossover design that assess the beneficial and harmful effects of pacing for hypertrophic cardiomyopathy were included. When crossover studies were identified, we considered data only from the first phase. DATA COLLECTION AND ANALYSIS: Data from included studies were extracted onto a pre-formed data extraction paper by two authors independently. Data was then entered into Review Manager 5.1 for analysis. Risk of bias was assessed using the guidance provided in the Cochrane Handbook. For dichotomous data, relative risk was calculated; and for continuous data, the mean differences were calculated. Where appropriate data were available, meta-analysis was performed. Where meta-analysis was not possible, a narrative synthesis was written. A QUROUM flow chart was provided to show the flow of papers. MAIN RESULTS: Five studies (reported in 10 papers) were identified. However, three of the five studies provided un-usable data. Thus the data from only two studies (reported in seven papers) with 105 participants were included for this review. There was insufficient data to compare results on all-cause mortality, cost effectiveness, exercise capacity, Quality of life and Peak O2 consumption.When comparing active pacing versus placebo pacing on exercise capacity, one study showed that exercise time decreased from (13.1 ± 4.4) minutes to (12.6 ± 4.3) minutes in the placebo group and increased from (12.1 ± 5.6) minutes to (12.9 ± 4.2) minutes in the treatment group (MD 0.30; 95% CI -1.54 to 2.14). Statistically significant data from the same study showed that left ventricular outflow tract obstruction decreased from (71 ± 32) mm Hg to (52 ± 34) mm Hg in the placebo group and from (70 ± 24) mm Hg to (33 ± 27) mm Hg in the active pacing group (MD -19.00; 95% CI -32.29 to -5.71). This study was also able to show that New York Heart Association (NYHA) functional class decreased from (2.5 ± 0.5) to (2.2 ± 0.6) in the inactive pacing group and decreased from (2.6 ± 0.5) to (1.7 ± 0.7) in the placebo group (MD -0.50; 95% CI -0.78 to -0.22).When comparing active pacing versus trancoronary ablation of septal hypertrophy (TASH), data from one study showed that NYHA functional class decreased from (3.2 ± 0.7) to (1.5 ± 0.5) in the TASH group and decreased from (3.0 ± 0.1) to (1.9 ± 0.6) in the pacemaker group. This study also showed that LV wall thickness remained unchanged in the active pacing group compared to reduction from (22 ± 4) mm to (17 ± 3) mm in the TASH group (MD 0.60; 95% CI -5.65 to 6.85) and that LV outflow tract obstruction decreased from (80 ± 35.5) mm Hg in the TASH group to (49.3 ± 37.7) mm Hg in the pacemaker group. AUTHORS' CONCLUSIONS: Trials published to date lack information on clinically relevant end-points. Existing data is derived from small trials at high risk of bias, which concentrate on physiological measures. Their results are inconclusive. Further large and high quality trials with more appropriate outcomes are warranted.

Sonothrombolysis in ST-Segment Elevation Myocardial Infarction Treated With Primary Percutaneous Coronary Intervention.

BACKGROUND: Preclinical studies have demonstrated that high mechanical index (MI) impulses from a diagnostic ultrasound transducer during an intravenous microbubble infusion (sonothrombolysis) can restore epicardial and microvascular flow in acute ST-segment elevation myocardial infarction (STEMI). OBJECTIVES: This study tested the clinical effectiveness of sonothrombolysis in patients with STEMI. METHODS: Patients with their first STEMI were prospectively randomized to either diagnostic ultrasound-guided high MI impulses during an intravenous Definity (Lantheus Medical Imaging, North Billerica, Massachusetts) infusion before, and following, emergent percutaneous coronary intervention (PCI), or to a control group that received PCI only (n = 50 in each group). A reference first STEMI group (n = 203) who arrived outside the randomization window was also analyzed. Angiographic recanalization before PCI, ST-segment resolution, infarct size by magnetic resonance imaging, and systolic function (LVEF) at 6 months were compared. RESULTS: ST-segment resolution occurred in 16 (32%) high MI PCI versus 2 (4%) PCI-only patients before PCI, and angiographic recanalization was 48% in high MI/PCI versus 20% in PCI only and 21% in the reference group (p < 0.001). Infarct size was reduced (29 ± 22 g high MI/PCI vs. 40 ± 20 g PCI only; p = 0.026). LVEF was not different between groups before treatment (44 ± 11% vs. 43 ± 10%), but increased immediately after PCI in the high MI/PCI group (p = 0.03), and remained higher at 6 months (p = 0.015). Need for implantable defibrillator (LVEF ≤30%) was reduced in the high MI/PCI group (5% vs. 18% PCI only; p = 0.045). CONCLUSIONS: Sonothrombolysis added to PCI improves recanalization rates and reduces infarct size, resulting in sustained improvements in systolic function after STEMI. (Therapeutic Use of Ultrasound in Acute Coronary Artery Disease; NCT02410330).

Prospective evaluation of cardiac ultrasound performance by general internal medicine physicians during a 6-month faculty development curriculum.

BACKGROUND: Point-of-care (POCUS) education is rapidly expanding within medical schools and internal medicine residency programs, but lack of trained faculty is a major barrier. While POCUS training can improve short-term outcomes, knowledge and skills rapidly decay without deliberate practice and feedback. The purpose of this study was to evaluate the performance of focused cardiac ultrasound (FCU) by volunteer general internal medicine (GIM) faculty participating in a longitudinal POCUS curriculum. METHODS: Participants: Nine GIM clinician-educators participated in a 6-month POCUS curriculum. Faculty performance was compared to three cardiology fellows. Three diagnostic cardiac sonographers (DCS) were also evaluated and served as the gold standard. EVALUATION: the primary outcome was a FCU efficiency score, calculated by dividing image quality score by exam duration. FCU exams were conducted on three standardized patients after completion of an introductory workshop, at 3 months, and at 6 months. Two blinded cardiologists scored the exams. ANALYSIS: mean efficiency scores were compared using a linear mixed effects model, followed by pairwise comparisons using Tukey's test. RESULTS: GIM faculty's FCU efficiency scores were maintained over the 6-month period (2.2, SE 1.0 vs. 3.8, SE 1.0, p = 0.076). Their scores at each session were similar to cardiology fellows (p > 0.69), but inferior to DCSs (p < 0.0001). CONCLUSION: GIM faculty participating in a POCUS curriculum maintained their FCU performance over 6 months with efficiency scores comparable to experienced cardiology fellows.