Diane Barker

Prolonged PR interval, first-degree heart block and adverse cardiovascular outcomes: a systematic review and meta-analysis

Objective First-degree atrioventricular block is frequently encountered in clinical practice and is generally considered a benign process. However, there is emerging evidence that prolonged PR interval may be associated with adverse outcomes. This study aims to determine if prolonged PR interval is associated with adverse cardiovascular outcomes and mortality. Methods We searched MEDLINE and EMBASE for studies that evaluated clinical outcomes associated with prolonged and normal PR intervals. Relevant studies were pooled using random effects meta-analysis for risk of mortality, cardiovascular mortality, heart failure, coronary heart disease, atrial fibrillation and stroke or transient ischaemic attack (TIA). Sensitivity analyses were performed considering the population type and the use of adjustments. Results Our search yielded 14 studies that were undertaken between 1972 and 2011 with 400u2005750 participants. Among the studies that adjusted for potential confounders, the pooled results suggest an increased risk of mortality with prolonged PR interval risk ratio (RR) 1.24 95% CI 1.02 to 1.51, five studies. Prolonged PR interval was associated with significant risk of heart failure or left ventricular dysfunction (RR 1.39 95% CI 1.18 to 1.65, three studies) and atrial fibrillation (RR 1.45 95% CI 1.23 to 1.71, eight studies) but not cardiovascular mortality, coronary heart disease or myocardial infarction or stroke or TIA. Similar observations were recorded when limited to studies of first-degree heart block. Conclusions Data from observational studies suggests a possible association between prolonged PR interval and significant increases in atrial fibrillation, heart failure and mortality. Future prospective studies are needed to confirm the relationships reported, consider possible mechanisms and define the optimal monitoring strategy for such patients.

Efficacy And Safety Of The Subcutaneous Implantable Cardioverter Defibrillator: A Systematic Review

Background Subcutaneous implantable cardioverter defibrillators (S-ICDs) are considered an alternative to conventional transvenous ICDs (TV-ICDs) in patients not requiring pacing. Methods We searched MEDLINE and EMBASE for studies evaluating efficacy and safety outcomes in S-ICD patients. Outcomes were pooled across studies. Results Sixteen studies were included with 5380 participants (mean age range 33–56 years). Short-term follow-up data were available for 1670 subjects. The most common complication was pocket infection, affecting 2.7%. Other complications included delayed wound healing (0.6%) and wound discomfort (0.8%). 3.8% of S-ICDs were explanted, most commonly for pocket infection. Mortality rates in hospital (0.4%) and during follow-up (3.4% from 12 studies reporting) were low. Incidence of ventricular arrhythmia varied from 0% to 12%. Overall shock efficacy exceeded 96%. Inappropriate shocks affected 4.3% and was most commonly caused by T-wave oversensing. Conclusions Although long-term randomised data are lacking, observational data suggest similar shock efficacy and short-term complication rates between the S-ICD and TV-ICD.

Effect of weekend admission on process of care and clinical outcomes for the management of acute coronary syndromes: a retrospective analysis of three UK centres

Objectives The effect of weekend versus weekday admission following acute coronary syndrome (ACS) on process of care and mortality remains controversial. This study aimed to investigate the ‘weekend-effect’ on outcomes using a multicentre dataset of patients with ST elevation myocardial infarction (STEMI) and non-ST elevation myocardial infarction/unstableu2009angina (NSTEMI/UA). Design This retrospective observational study used propensity score (PS) stratification to adjust estimates of weekend effect for observed confounding. Logistic regression was used to estimate odds ratios (ORs) for binary outcomes and time-to-event endpoints were modelled using Cox proportional hazards to estimate hazard ratios (HRs). Setting Three tertiary cardiac centres in England and Wales that contribute to the Myocardial Ischaemia National Audit Project. Participants Between January 2010 and March 2016, 17u2009705 admissions met the study inclusion criteria, 4327 of which were at a weekend. Primary and secondary outcomes Associations were studied between weekend admissions and the following primary outcome measures: in-hospital mortality, 30-day mortality and long-term survival; secondary outcomes included several processes of care indicators, such as time to coronary angiography. Results After PS stratification adjustment, mortality outcomes were similar between weekend and weekday admission across patients with STEMI and NSTEMI/UA. Weekend admissions were less likely to be discharged within 1u2009day (HR 0.72, 95%u2009CI 0.66 to 0.78), but after 4u2009days the length of stay was similar (HR 0.97, 95%u2009CI 0.90 to 1.04). Fewer patients with NSTEMI/UA received angiography between 0 and 24u2009hours at a weekend (HR 0.71, 95%u2009CI 0.65 to 0.77). Weekend patients with STEMI were less likely to undergo an angiogram within 1u2009hour, but there was no significant difference after this time point. Conclusion Patients with ACS had similar mortality and processes of care when admitted on a weekend compared with a weekday. There was evidence of a delay to angiography for patients with NSTEMI/UA admitted at the weekend.

Early Readmissions After Acute Myocardial Infarction

This study aims to evaluate the rate, predictors, and causes of 30-day readmissions in a single tertiary hospital in the United Kingdom. We conducted a retrospective study of all patients admitted between 2012 and 2014 with a diagnosis of acute myocardial infarction, who were in the Myocardial Infarction National Audit Project register. Data on patient demographics, comorbidities, care received, and in-hospital mortality were collected. Rates of 30-day readmission and causes of readmission were evaluated. Univariate and multiple logistic regressions were used to identify predictors of all-cause, cardiac, and noncardiac readmission. A total of 1,869 patients were included in the analysis and 171 had an unplanned readmission with 30 days (9%). Noncardiac problems represented half of all readmissions with the dominant cause noncardiac chest pain (50%). A variety of other noncardiac causes for readmission were identified and the most common were lower respiratory tract infection (4.3%), gastrointestinal problems (4.9%), bleeding (3.7%), dizziness, syncope, or fall (3.0%), and pulmonary embolus (2.4%). For cardiac causes of readmissions, common causes included acute coronary syndrome (17.1%), stable angina (11.6%), and heart failure (9.8%). Readmitted patients were more likely to be older, anemic, and less likely to receive coronary angiogram and percutaneous coronary intervention. After adjustment, the only predictor of all-cause readmission was older age. For noncardiac readmission, previous myocardial infarction was associated with significantly fewer readmissions. Our results suggest that early readmission after discharge with diagnosis of acute myocardial infarction is common. Chest pain is the most frequent cause of readmission, and interventions to reduce noncardiac chest pain admissions are needed.

Discharge against medical advice after hospitalisation for acute myocardial infarction

Background Discharge against medical advice (AMA) occurs infrequently but is associated with poor outcomes. There are limited descriptions of discharges AMA in national cohorts of patients with acute myocardial infarction (AMI). This study aims to evaluate discharge AMA in AMI and how it affects readmissions. Methods We conducted a cohort study of patients with AMI in USA in the Nationwide Readmission Database who were admitted between the years 2010 and 2014. Descriptive statistics were presented for variables according to discharge home or AMA. The primary end point was all-cause 30-day unplanned readmissions and their causes. Results 2663 019 patients were admitted with AMI of which 10.3% (n=162u2009070) of 1569 325 patients had an unplanned readmission within 30u2009days. The crude rate of discharge AMA remained stable between 2010 and 2014 at 1.5%. Discharge AMA was an independent predictor of unplanned all-cause readmissions (OR 2.27 95%u2009CI 2.14 to 2.40); patients who discharged AMA had >twofold increased crude rate of readmission for AMI (30.4% vs 13.4%) and higher crude rate of admissions for neuropsychiatric reasons (3.2% vs 1.3%). After adjustment, discharge AMA was associated with increased odds of readmissions for AMI (OR 3.65 95%u2009CI 3.31 to 4.03, p<0.001). We estimate that there are 1420 excess cases of AMI among patients who discharged AMA. Conclusions Discharge AMA occurs in 1.5% of the population with AMI and these patients are at higher risk of early readmissions for re-infarction. Interventions should be developed to reduce discharge AMA in high-risk groups and initiate interventions to avoid adverse outcomes and readmission.

Concerns about latest NICE guidelines on acute heart failure.

We have several comments on the summary of the National Institute for Health and Care Excellence (NICE) acute heart failure guideline.1nnThe guideline fails to define acute heart failure and to differentiate it from hospital admission for heart failure. The two conditions are not synonymous. Acute heart failure is the final clinical presentation of differing haemodynamic “phenotypes,” with less …

173 A generic method to assess the adequacy of individual maternal cardiac reserve to tolerate the demands of pregnancy and labour

Introduction Clinicians often feel apprehensive when managing pregnant patients with heart disease. To complement current evaluation, we have developed a new method of directly assessing the individual patients cardiac functional reserve through stress testing. Pregnant mothers with and without heart disease were studied to test the hypothesis that pregnant cardiac patients who possess cardiac reserve equivalent to that of controls can tolerate the usual demands of pregnancy, labour and puerperium. Methods Fifty-one pregnant women with heart disease (mean age 30.7±6.5 (range 21–42), mean gestation 25.6±8.6u2005weeks) and 102 healthy pregnant women (mean age 31.4±5.0, (range 19–41), mean gestation 25.1±9.2u2005weeks) underwent maximal symptom-limited treadmill cardiopulmonary exercise testing. Fifty-nine non-pregnant women (mean age 32.7±5.1 (range 20–41)u2005years) were similarly tested and used as a control group. Cardiac output (CO) was measured at peak exercise using the CO2 re-breathing method. Cardiac power output (CPO) was calculated as the product of CO and mean arterial pressure. A composite endpoint including maternal death, fetal death, emergency caesarean section for maternal distress and significant morbidities was determined. Results All tests were performed without significant complications. Employing data from a previous study of haemodynamics during labour in healthy women, the mean CPO required during peak labour is 2.6u2005W. This value was adopted for investigation as the minimum required for an average woman to cope with the circulatory demands of normal labour. The healthy controls had a mean peak CPO (PkCPO) of 3.79±0.6u2005W and all non-pregnant women had PkCPO exceeding 2.6u2005W. The majority of heart disease patients were able to achieve PkCPO values overlapping their healthy counterparts. Only a small proportion of the cardiac patients had PkCPO values lower than the 2.6u2005W cutoff. Women were significantly more likely to have uncomplicated pregnancy, labour and puerperium if able to achieve PkCPO>2.6u2005W (OR 8.1, 95% CI 1.8 to 37.0, p=0.023). Pregnant women in NYHA class I had PkCPO values indistinguishable from controls (mean 3.98±0.77u2005W, NS); whereas symptomatic pregnant women had significantly lower values (mean 3.15±0.71W, p<0.005). Conclusions Direct measurement of cardiac functional reserve capacity can be performed by maximal cardiopulmonary exercise testing with non-invasive assessment of PkCPO, which can be safely undertaken during pregnancy. A cutoff value of PkCPO 2.6 W was identified as the lower limit for healthy women, corresponding to that required for normal labour. Most cardiac patients studied had PkCPO values comfortably above this cutoff, and all asymptomatic (NYHA I) and low risk cardiac patients had PkCPO values similar to controls. Measurement of PkCPO allows pregnant patients to be further classified into those with adequate vs limited cardiac reserve, supplementary to existing risk stratification methods.

99 Is Vo2max/Kg a reliable indicator of cardiac dysfunction in overweight heart failure patients?

Background Peak O2 consumption (Vo2max) of ≤14u2005ml/kg/min has been widely accepted as being indicative of poor cardiac function warranting consideration for transplantation (Circulation 2010; 122:173). We examined whether this variable is a good indicator of cardiac function in overweight heart failure (HF) patients. Methods We compared the cardiopulmonary exercise performance and non-invasive haemodynamics of overweight (BMI >34u2005kg/m2) and non-overweight (BMI ≤30) male heart failure patients in NYHA Classes II and III, with those of healthy male volunteers with no known cardiovascular diseases (n=101, age 43.2±18.1(SD)u2005years, BMI 26.0±3.1) as controls. Their physical and cardiac functional reserves were measured during treadmill exercise testing with standard respiratory gas analyses and rebreathing method of non-invasively measuring cardiac outputs during peak exercise. Results Consecutive overweight HF were screened and 24 patients (age 49±8(SD)u2005years, BMI 44.9±6.8, NYHA 2.50±0.50) managed to exercise to acceptable cardiopulmonary limits (peak RER=1.01±0.12), and achieved Vo2max of 16.8±4.6u2005mls/kg/min which was significantly lower than controls (37.0±10.7u2005mls/kg/min, p<10−6) and also lower than those of 30 non-overweight HF counterparts (20.0±3.7u2005mls/kg/min, p=0.0019, age 49±15u2005years, BMI 25.0±2.9, NYHA 2.48±0.51). As shown in Abstract 99 figure 1, the overweight HF patients had Vo2max values which distributed around the 14u2005mls/kg/min cut-off value, and 9 of whom were indeed below this cut-off value. However, the uncorrected Vo2max were higher than those of non-overweight counterparts (Overweight: 2575±748 vs 1594±325 mls/min, p<10−6), and its range of 1485–4210u2005mls/min overlapped with the range of 1244–5774u2005mls/min in controls. The peak cardiac power output (CPOmax, 4.5±1.6u2005W, minimum 2.7u2005W) of overweight HF patients were clearly above those of non-overweight (2.4±0.6u2005W, p<10−6, Abstract 99 figure 2) and all above the transplant cut-off value of 1.5u2005W.Abstract 99 Figure 1 Abstract 99 Figure 2 Conclusion These results indicate that in principle Vo2max in ml/kg/min as an indirect indicator of cardiac function or for cardiac transplantation selection is unreliable when applied to overweight heart failure patients. Extending this concept to the entire spectrum of body weights, the practice of correcting Vo2max by body weight in cardiological practice would also require urgent reconsideration.

066 Vasodilatory capacity at peak exercise in treated heart failure patients are not diminished

Background Previous received dogma has propagated the concept that heart failure (HF) patients have compromised vasodilatory capacity during exercise through various vascular mechanisms, thereby reducing their exercise capacity through peripheral (vascular) factors rather than central (cardiac) factors. We tested whether such a concept is still valid in modern HF patients receiving current standard HF therapies. Methods and Results We recruited 150 female participants (133 normal healthy controls, age 48.5±13.1 (SD) years; 17 DCM patients, age 41.5±14.2u2005years) with no known coronary or other vascular diseases, and compared their central haemodynamic responses during volitional maximal exercise. The exercise capacity of controls spanned the same ranges as those of the HF patients. All patients performed symptom-limited cardiopulmonary exercise testing (CPX) with breath-by-breath analyses of respiratory gases and non-invasive haemodynamic measurements employing standard auscultatory sphygmomanometric and rebreathing methods. The patients performed a total of 30 CPXs. The peak O2 consumption spanned from 1.20 to 2.45u2005L/min in DCM patients and from 1.15 to 2.44u2005L/min in controls. As shown in the figure, at peak exercise the systemic vascular resistances (SVR) of DCM patients were lower (532±154u2005dyn.s.cm-5) than those of controls (654±118u2005dyn.s.cm-5). Conclusion With modern HF therapy, the lower peak exercise SVR in HF patients compared to normal healthy controls demonstrates that there is no evidence of compromised systemic vasodilatory capacities in HF patients. The long-held dogma of vasodilatory incapacity in HF propagated >3u2005decades ago is no longer valid nowadays. Abstract 66 Figure 1