Utility of TTR-INR guided warfarin adjustment protocol to improve time in therapeutic range in patients with atrial fibrillation receiving warfarin

Warfarin remains the most prescribed oral anticoagulant of choice in atrial fibrillation (AF) patient in resource-limited settings. Despite evidence linking Time in Therapeutic Range (TTR) to patient outcomes, its use in clinical practice is not widespread. This prospective study explores the impact of a TTR-INR guided Warfarin adjustment protocol on TTR in AF patients. Conducted at the Warfarin clinic of King Chulalongkorn Memorial Hospital. TTR was calculated using the Rosendaal linear interpolation method at baseline, and then at 6 and 12 months post-protocol implementation. The primary outcome was the improvement in TTR following the protocol's implementation. The study analyzed 57 patients, with a mean age of 72 years and an even gender distribution. At baseline, 53% of patients had a TTR of less than 65%. However, TTR significantly improved from 65% at baseline to 80% after 12 months of protocol implementation (p < 0.001). Furthermore, there was a significant increase in the proportion of patients with a TTR of 65% or more, from 47 to 88% (p < 0.001). During the follow-up period in the first 12 months, three patients died, but no ischemic or major bleeding events occurred. The significant improvement in TTR after 12 months of protocol implementation suggests that this strategy could provide additional value in improving TTR and outcomes in AF patients receiving Warfarin.

Radiofrequency ablation of atrial fibrillation: A 14 years' experience at a tertiary care center in Thailand

BACKGROUND

The result of atrial fibrillation (AF) ablation varies across centers. Most data are derived from the Western world, while data from Southeast Asian countries are lacking. We aimed to investigate the outcomes of AF ablation in Thailand.

METHOD

We performed a retrospective analysis of patients who underwent AF ablation in a tertiary care center, between the years 2006-2020. Details of AF ablation, including pulmonary vein isolation (PVI), and complex fractionated atrial electrogram (CFAE) ablation, were classified. The success rate of AF ablation is determined by freedom from AF beyond 3 months blanking period. Combined success rate of AF ablation was reported along with the success rate of each technique (PVI, CFAE, and combine PVI plus CFAE).

RESULT

We identified a total of 171 patients who underwent the first AF ablation. Ninety-four (55%) patients went through PVI, 55 (32%) patients for CFAE ablation, and 22 (13%) patients for PVI plus CFAE ablation. Overall freedom from AF was 73% at 12 months, 66% at 24 months, and 55% at 36 months. The success rate of PVI was 79% at 12 months, 74% at 24 months, and 59% at 36 months. The success rate of CFAE ablation was 63% at 12 months, 51% at 24 months, and 47% at 36 months.

CONCLUSION

Catheter ablation of AF is proven safe and effective in Thai population.

Cannabis and adverse cardiovascular events: A systematic review and meta-analysis of observational studies

Background

Cannabis is the most used illicit drug in the world. Global trends of decriminalization and legalization of cannabis lead to various forms of cannabis use and bring great concerns over adverse events, particularly in the cardiovascular (CV) system. To date, the association between cannabis and adverse CV events is still controversial.

Purpose

We aim to conduct a systematic review and meta-analysis to assess the adverse CV events from cannabis use.

Patients and methods

A systematic search for publications describing the adverse CV events of cannabis use, including acute myocardial infarction (MI) and stroke, was performed via PubMed, Scopus, and Cochrane Library databases. Data on effect estimates in individual studies were extracted and combined via random-effects meta-analysis using the DerSimonian and Laird method, a generic inverse-variance strategy.

Results

Twenty studies with a total of 183,410,651 patients were included. The proportion of males was 23.7%. The median age and follow-up time were 42.4 years old (IQR: 37.4, 50.0) and 6.2 years (IQR: 1.7, 27.7), respectively. The prevalence of cannabis use was 1.9%. Cannabis use was not significantly associated with acute MI (pooled odds ratio (OR): 1.29; 95%CI: 0.80, 2.08), stroke (pooled OR 1.35; 95%CI: 0.74, 2.47), and adverse CV events (pooled OR: 1.47; 95%CI: 0.98, 2.20).

Conclusion

The risk of adverse CV events including acute MI and stroke does not exhibit a significant increase with cannabis exposure. However, caution should be exercised when interpreting the findings due to the heterogeneity of the studies.

Arrhythmias after SARS-CoV-2 Vaccination in Patients with a Cardiac Implantable Electronic Device: A Multicenter Study

One of the most concerning adverse events related to the SARS-CoV-2 vaccination is arrhythmia. To ascertain the relationship between vaccination and arrhythmic events, we studied the occurrence of arrhythmia in patients with cardiac implantable electronic devices (CIEDs) before and after a SARS-CoV-2 vaccination. Patients with CIEDs aged ≥18 who visited the CIED clinic at King Chulalongkorn Memorial Hospital and Vajira hospital from August 2021 to February 2022 were included. Information about the SARS-CoV-2 vaccination and side effects was obtained. One hundred eighty patients were included in our study, which compared the incidence of arrhythmias in the 14 days post-vaccination to the 14 days before vaccination. The median age was 70 years. The number of patients who received one, two, and three doses of the vaccine was 180, 88, and 4, respectively. ChAdOx1 was the primary vaccine used in our institutes, accounting for 86% of vaccinations. The vaccination was significantly associated with a 73% increase incidence of supraventricular tachycardia (SVT). In an adjusted model, factors associated with the incidence of SVT were the post-vaccination period, female sex, increasing BMI, chronic kidney disease, and a history of atrial fibrillation. Increased ventricular arrhythmia (VA) episodes were also associated with the post-vaccination period, female sex, decreasing BMI, and chronic kidney disease, but to a lesser degree than those with SVT episodes. No life-threatening arrhythmia was noted in this study. In conclusion, the incidence of arrhythmia in patients implanted with CIEDs was significantly increased after the SARS-CoV-2 vaccination.

Improve the Prevention of Sudden Cardiac Arrest in Patients With Post-Acute Myocardial Infarction

BACKGROUND

Implantable cardioverter-defibrillator (ICD) implantation to prevent sudden cardiac death (SCD) in post-myocardial infarction (MI) patients varies by geography but remains low in many regions despite guideline recommendations.

OBJECTIVES

This study aimed to characterize the care pathway of post-MI patients and understand barriers to referral for further SCD risk stratification and management in patients meeting referral criteria.

METHODS

This prospective, nonrandomized, multi-nation study included patients ≥18 years of age, with an acute MI ≤30 days and left ventricular ejection fraction <50% ≤14 days post-MI. The primary endpoint was defined as the physician's decision to refer a patient for SCD stratification and management.

RESULTS

In total, 1,491 post-MI patients were enrolled (60.2 ± 12.0 years of age, 82.4% male). During the study, 26.7% (n = 398) of patients met criteria for further SCD risk stratification; however, only 59.3% of those meeting criteria (n = 236; 95% CI: 54.4%-64.0%) were referred for a visit. Of patients referred for SCD risk stratification and management, 94.9% (n = 224) attended the visit of which 56.7% (n =127; 95% CI: 50.1%-63.0%) met ICD indication criteria. Of patients who met ICD indication criteria, 14.2% (n = 18) were implanted.

CONCLUSIONS

We found that ∼40% of patients meeting criteria were not referred for further SCD risk stratification and management and ∼85% of patients who met ICD indications did not receive a guideline-directed ICD. Physician and patient reasons for refusing referral to SCD risk stratification and management or ICD implant varied by geography suggesting that improvement will require both physician- and patient-focused approaches. (Improve Sudden Cardiac Arrest [SCA] Bridge Study; NCT03715790).

Benefit of Atrial Overdrive Pacing in Patients with Sleep Apnea: A Meta-Analysis

BACKGROUND

Sleep apnea is one of the most common conditions around the world. This disorder can significantly impact cardiovascular morbidity and mortality. Atrial overdrive pacing (AOP) is a treatment modality that can potentially decrease respiratory events. There is currently a lack of evidence to confirm the benefits of AOP. We aimed to assess the impact of AOP in patients with obstructive sleep apnea (OSA), central sleep apnea (CSA), and mixed type.

METHODS

A literature search for studies that reported the impact on apnea-hypopnea index (AHI) by cardiac implantable electronic devices with different pacing modes was conducted using MEDLINE, Embase, and Cochrane Database from inception through July 2020. Pooled standard mean difference with 95%CI was calculated using a random-effects model.

RESULTS

Fifteen studies, including thirteen randomized studies and two observational studies containing 440 patients, were identified. The standard mean difference in apnea-hypopnea index of atrial overdrive pacing demonstrated less duration of apnea/hypopnea in patients with atrial overdrive pacing (AOP) (SMD -0.29, 95%CI: -0.48, -0.10, I² = 57%). Additional analysis was performed to assess the effect of atrial overdrive pacing in patients with or without severe sleep apnea syndrome (mean AHI < 30 defined as non-severe). There was no statistically significant difference in standardized mean in AHI in both subgroups between AOP and control groups (SMD -0.25, severe sleep apnea syndrome SMD -0.03, I² = 0.00%).

CONCLUSIONS

AOP was associated with a statistically significant reduction in AHI, but the magnitude of reduction was small. AOP may potentially be used as an adjunctive treatment with other modalities in treating patients with sleep apnea.

Factors predicting poor anticoagulant control on warfarin in a Thai population with non-valvular atrial fibrillation (NVAF): the ACAChE score

Background

In many low- to middle-income countries in Asia, patients with NVAF usually received warfarin for thromboembolic prevention due to cost-effectiveness. The SAMe-TT2R2 score has been proposed to predict TTR in NVAF patients. However, the SAMe-TT2R2 score has not been much validated in Asian population. Interestingly, it may overestimate patients who had TTR < 65% due to regarding being Asians as a risk factor.

Objectives

To determine the factors predicting poor anticoagulant control on warfarin, create new scoring system, and compare with the SAMe-TT2R2 score in a Thai population with NVAF.

Methods

This is a retrospective study in a tertiary care hospital. We enrolled NVAF patients who received warfarin from January 2014 to December 2018. TTR was calculated based on Rosendaal method. Multiple logistic regression and AUC-ROC curve were used for analysis.

Results

A total of 864 patients were enrolled with mean age of 73.6 ± 11.58 years. The mean TTR was 48.1 ± 25.2%. Using multivariate regression analysis, the predictive factors for TTR < 65% were antiplatelet use (OR 4.49, p ≤ 0.001), LVEF < 40% (OR 1.92, p = 0.037), chronic kidney disease (GFR < 50 ml/min/1.73 m2) (OR 1.68, p = 0.013), history of CHF (OR 1.7, p = 0.047), and age ≥ 75 years (OR 1.4, p = 0.037). Based on the regression coefficients, we developed the new scoring system called ACAChE score [A, antiplatelet use (4 points); C, chronic kidney disease, GFR < 50 ml/min/1.73 m2 (2 points); A, age ≥ 75 years (1 point); Ch, history of CHF (2 points); E, LVEF < 40% (2 points)]. ROC curve showed discrimination performance of the ACAChE score and SAMe-TT2R2 score for prediction of TTR < 65% with the C-statistic of 0.62 (95%CI 0.57–0.65) and 0.54 (95%CI 0.50–0.58), respectively.

Conclusion

In Thai NVAF patients, the ACAChE score (antiplatelet use, chronic kidney disease (GFR < 50 ml/min/1.73 m2), age ≥ 75 years, history of congestive heart failure, and LVEF < 40%) has better prediction for TTR < 65% than SAMe-TT2R2 score. Thus, it expected to guide the selection of oral anticoagulation in Asian patients with NVAF.

Resumption of interatrial conduction after atrial premature beat in baseline interatrial aberrancy

Interatrial block (IAB) is a delay or blockage of interatrial conduction from the right atrium to the left atrium, causing prolongation of the P‐wave duration on the electrocardiogram. This condition is unfortunately not uncommon in clinical practice, especially among the elderly. It is often overlooked because the P wave is small and abnormalities can be difficult to detect. An isolated IAB does not usually cause any abnormal symptoms and may not require any specific treatment. Nevertheless, a relationship between an IAB and other cardiovascular conditions including left atrial electromechanical dysfunction, atrial remodeling, atrial fibrosis, atrial fibrillation, and stroke has been reported. Early diagnosis of this condition is critical. This case report presents a functional interatrial block or interatrial aberrancy that returned to normal after an atrial premature complex where the interatrial conduction remained normal in subsequent beats.

Reduced Cardiac Index Reserve and Hypovolemia in Severe Falciparum Malaria

BACKGROUND

Impaired microvascular perfusion is central to the development of coma and lactic acidosis in severe falciparum malaria. Refractory hypotension is rare on admission but develops frequently in fatal cases. We assessed cardiac function and volume status in severe falciparum malaria and its prognostic significance.

METHODS

Patients with severe (N = 101) or acute uncomplicated falciparum malaria (N = 83) were recruited from 2 hospitals in India and Bangladesh, and healthy participants (N = 44) underwent echocardiography.

RESULTS

Patients with severe malaria had 38% shorter left ventricular (LV) filling times and 25% shorter LV ejection times than healthy participants because of tachycardia; however, stroke volume, LV internal diameter in diastole (LVIDd), and LV internal diameter in systole (LVIDs) indices were similar. A low endocardial fraction shortening (eFS) was present in 17% (9 of 52) of severe malaria patients. Adjusting for preload and afterload, eFS was similar in health and severe malaria. Fatal cases had smaller baseline LVIDd and LVIDs indices, more collapsible inferior vena cavae (IVC), and higher heart rates than survivors. The LVIDs and IVC collapsibility were independent predictors for mortality, together with base excess and Glasgow Coma Scale.

CONCLUSIONS

Patients with severe malaria have rapid ejection of a normal stroke volume. Fatal cases had features of relative hypovolemia and reduced cardiac index reserve.

Cell-Free Hemoglobin Is Associated With Increased Vascular Resistance and Reduced Peripheral Perfusion in Severe Malaria

BACKGROUND

In severe falciparum malaria, unlike sepsis, hypotension on admission is uncommon. We hypothesized that low nitric oxide bioavailability due to the presence of cell-free hemoglobin (CFH) increases vascular tone in severe malaria.

METHODS

Patients with severe malaria (n = 119), uncomplicated malaria (n = 91), or suspected bacterial sepsis (n = 56), as well as healthy participants (n = 50), were recruited. The systemic vascular resistance index (SVRI) was estimated from the echocardiographic cardiac index and the mean arterial pressure.

RESULTS

SVRI and hematocrit levels were lower and plasma CFH and asymmetric dimethylarginine levels were higher in patients with malaria, compared with healthy participants. In multivariate linear regression models for mean arterial pressure or SVRI in patients with severe malaria, hematocrit and CFH but not asymmetric dimethylarginine were significant predictors. The SVRI was lower in patients with suspected bacterial sepsis than in those with severe malaria, after adjustment for hematocrit and age. Plasma CFH levels correlated positively with the core-peripheral temperature gradient and plasma lactate levels and inversely with the perfusion index. Impaired peripheral perfusion, as reflected by a low perfusion index or a high core-peripheral temperature gradient, predicted mortality in patients with severe malaria.

CONCLUSIONS

CFH is associated with mean arterial pressure, SVRI, and peripheral perfusion in patients with severe malaria. This may be mediated through the nitric oxide scavenging potency of CFH, increasing basal vascular tone and impairing tissue perfusion.

Does reduced oxygen delivery cause lactic acidosis in falciparum malaria? An observational study

Background

Lactic acidosis with an elevated lactate–pyruvate ratio suggesting anoxia is a common feature of severe falciparum malaria. High lactate levels are associated with parasitized erythrocyte sequestration in the microcirculation. To assess if there is an additional contribution to hyperlactataemia from relatively inadequate total oxygen delivery, oxygen consumption and delivery were investigated in patients with malaria.

Methods

Adult Bangladeshi and Indian patients with uncomplicated (N = 50) or severe (N = 46) falciparum malaria or suspected bacterial sepsis (N = 27) and healthy participants as controls (N = 26) were recruited at Chittagong Medical College Hospital, Chittagong, Bangladesh and Ispat General Hospital, Rourkela, India. Oxygen delivery (DO₂I) was estimated from pulse oximetry, echocardiographic estimates of cardiac index and haematocrit. Oxygen consumption (VO₂I) was estimated by expired gas collection.

Results

VO₂I was elevated in uncomplicated median (IQR) 185.1 ml/min/m² (135–215.9) and severe malaria 192 ml/min/m² (140.7–227.9) relative to healthy persons 107.9 ml/min/m² (69.9–138.1) (both p < 0.001). Median DO₂I was similar in uncomplicated 515 ml/min/m² (432–612) and severe 487 ml/min/m² (382–601) malaria and healthy persons 503 ml/min/m² (447–517) (p = 0.27 and 0.89, respectively). The VO₂/DO₂ ratio was, therefore, increased by similar amounts in both uncomplicated 0.35 (0.28–0.44) and severe malaria 0.38 (0.29–0.48) relative to healthy participants 0.23 (0.17–0.28) (both p < 0.001). VO₂I, DO₂I and VO₂/DO₂ did not correlate with plasma lactate concentrations in severe malaria.

Conclusions

Reduced total oxygen delivery is not a major contributor to lactic acidosis in severe falciparum malaria.

Electronic supplementary material

The online version of this article (10.1186/s12936-019-2733-y) contains supplementary material, which is available to authorized users.

Combined mechanism of refractory shock in primary cardiac lymphoma: a rare dilemma

Primary cardiac lymphoma is very rare, and usually manifests after the fifth decade of life. The lack of typical manifestations makes it difficult to diagnose at an early stage that can be discovered only by echocardiography. The location of the tumour often results in cardiac compromise, which prevents the delivery of potentially curative therapies. Clinical presentations may depend on flow obstruction, infiltration of adjacent tissues, tumour embolisation, and atrioventricular (AV) disturbances. We report a rare case of primary cardiac lymphoma that presented with clinical signs of shock from two distinct mechanisms. The first mechanism was intermittent complete AV block that was caused by disruption of the electrical conduction system from tumour infiltration in addition to direct mechanical compression of the atrioventricular node by the tumour. The second mechanism, subtotal RV inflow obstruction from the bulky mass contributed to compromising venous return, which played a major role of refractory shock in this case.