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.

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).

T-Peak to T-End Interval for Prediction of Positive Response to Ajmaline Challenge Test in Suspected Brugada Syndrome Patients.

BACKGROUND: Brugada syndrome (BrS) is diagnosed in patients with ST-segment elevation with coved-type morphology in the right precordial leads, occurring spontaneously or after provocative drugs. Due to electrocardiographic (ECG) inconsistency, provocative drugs, such as sodium-channel blockers, are useful for unmasking BrS. Ajmaline is superior to flecainide and procainamide to provoke BrS. Prolonged T-peak to T-end (TpTe) is associated with an increased risk of ventricular arrhythmia and sudden cardiac death in Brugada syndrome patients. OBJECTIVE: This study aimed to investigate the predictive value of T-peak to T-end interval and corrected T-peak to T-end interval for predicting the positive response of the ajmaline challenge test in suspected Brugada syndrome patients. METHODS: Patients who underwent the ajmaline test in our center were enrolled. Clinical characteristics and electrocardiographic parameters were analyzed, including TpTe, corrected TpTe, QT, corrected QT(QTc) interval, and S-wave duration, compared with the result of the ajmaline challenge test. RESULTS: The study found that TpTe and corrected TpTe interval in suspected BrS patients were not significantly associated with a positive response to the ajmaline challenge test. CONCLUSIONS: The T-peak to T-end interval and corrected T-peak to T-end interval could not predict the positive response of the ajmaline challenge test in suspected Brugada syndrome patients.

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.

Higher prevalence of QTc interval prolongation among virologically suppressed older people with HIV.

OBJECTIVE: To assess the prevalence, and factors associated with QTc interval prolongation, among 383 virologically suppressed people with HIV (PWH), without evidence of cardiovascular disease and active opportunistic infections in Thailand. DESIGN: Cross-sectional study. METHODS: Resting 12-lead digital ECGs were performed in 2019. QT interval corrected for heart rate (QTc) >450 ms in males and >460 ms in females was defined as QTc interval prolongation. We used multivariable logistic regression to investigate factors associated with QTc interval prolongation. RESULTS: Mean (standard deviation) age was 56 (5.5) years and 42% were female. The median current CD4+ was 619 (interquartile range [IQR] 487, 769) cells/mm 3 . The median duration of antiretroviral therapy (ART) was 11.9 (IQR 7.1-16.1) years. Commonly used ART were rilpivirine (37.9%), efavirenz (20.1%), atazanavir/ritonavir (15.7%), lopinavir/ritonavir (12.3%) and dolutegravir (5%). The prevalence of QTc interval prolongation was 22.7%. In multivariable analysis, older age (odds ratio [OR] 1.07, 95% confidence interval [CI] 1.02-1.12, P  = 0.005), female sex (OR 1.69, 95% CI 1.01-2.82, P  = 0.046) and increasing BMI (OR 1.08, 95% CI 1.01-1.15, P  = 0.03) were associated with QTc interval prolongation. With every 1-year increase in age, the odds of QTc interval prolongation increased by 7%. CONCLUSIONS: In this well-suppressed aging Asian HIV cohort, the prevalence of QTc interval prolongation was relatively high, and associated with increasing age, female sex, and higher BMI. For PLWH with these characteristics, QTc interval should be monitored before and after initiating any medications known to prolong QTc intervals, to prevent fatal cardiac arrhythmias.

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.

Home Blood Pressure Control and Drug Prescription Patterns among Thai Hypertensives: A 1-Year Analysis of Telehealth Assisted Instrument in Home Blood Pressure Monitoring Nationwide Pilot Project.

BACKGROUND: Several interventions have been proposed to improve hypertension control with various outcomes. The home blood pressure (HBP) measurement is widely accepted for assessing the response to medications. However, the enhancement of blood pressure (BP) control with HBP telemonitoring technology has yet to be studied in Thailand. OBJECTIVE: To evaluate the attainment of HBP control and drug prescription patterns in Thai hypertensives at one year after initiating the TeleHealth Assisted Instrument in Home Blood Pressure Monitoring (THAI HBPM) nationwide pilot project. METHODS: A multicenter, prospective study enrolled treated hypertensive adults without prior regular HBPM to obtain monthly self-measured HBP using the same validated, oscillometric telemonitoring devices. The HBP reading was transferred to the clinic via a cloud-based system, so the physicians can adjust the medications at each follow-up visit on a real-life basis. Controlled HBP is defined as having HBP data at one year of follow-up within the defined target range (<135/85 mmHg). RESULTS: A total of 1,177 patients (mean age 58 ± 12.3 years, 59.4% women, 13.1% with diabetes) from 46 hospitals (81.5% primary care centers) were enrolled in the study. The mean clinic BP was 143.9 ± 18.1/84.3 ± 11.9 mmHg while the mean HBP was 134.4 ± 15.3/80.1 ± 9.4 mmHg with 609 (51.8%) patients having HBP reading <135/85 mmHg at enrollment. At one year of follow-up after implementing the HBP telemonitoring, 671 patients (57.0%) achieved HBP control. Patients with uncontrolled HBP had a higher prevalence of dyslipidemia and greater waist circumference than the controlled group. The majority of uncontrolled patients were still prescribed only one (36.0%) or two drugs (34.4%) at the end of the study. The antihypertensive drugs were not uptitrated in 136 (24%) patients with uncontrolled HBP at baseline. Calcium channel blocker was the most prescribed drug class (63.0%) followed by angiotensin-converting enzyme inhibitor (44.8%) while the thiazide-type diuretic was used in 18.9% of patients with controlled HBP and 16.4% in uncontrolled patients. CONCLUSION: With the implementation of HBP telemonitoring, the BP control rate based on HBP analysis was still low. This is possibly attributed to the therapeutic inertia of healthcare physicians. Calcium channel blocker was the most frequently used agent while the diuretic was underutilized. The long-term clinical benefit of overcoming therapeutic inertia alongside HBP telemonitoring needs to be validated in a future study.

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.

Hypertension Subtypes among Thai Hypertensives: An Analysis of Telehealth-Assisted Instrument in Home Blood Pressure Monitoring Nationwide Pilot Project.

BACKGROUND: White-coat hypertension (HT), masked HT, HT with white-coat effect, and masked uncontrolled HT are well-recognized problems of over- and undertreatment of high blood pressure in real-life practice. However, little is known about the true prevalence in Thailand. OBJECTIVES: To examine the prevalence and characteristics of each HT subtype defined by mean home blood pressure (HBP) and clinic blood pressure (CBP) using telemonitoring technology in Thai hypertensives. METHODS: A multicenter, observational study included adult hypertensives who had been diagnosed for at least 3 months based on CBP without the adoption of HBP monitoring. All patients were instructed to manually measure their HBP twice a day for the duration of at least one week using the same validated automated, oscillometric telemonitoring devices (Uright model TD-3128, TaiDoc Corporation, Taiwan). The HBP, CBP, and baseline demographic data were recorded on the web-based system. HT subtypes were classified according to the treatment status, CBP (≥or <140/90 mmHg), and mean HBP (≥or <135/85 mmHg) into the following eight subtypes: in nonmedicated hypertensives, there are four subtypes that are normotension, white-coat HT, masked HT, and sustained HT; in treated hypertensives, there are four subtypes that are well-controlled HT, HT with white-coat effect, masked uncontrolled HT, and sustained HT. RESULTS: Of the 1,184 patients (mean age 58 ± 12.7 years, 59% women) from 46 hospitals, 1,040 (87.8%) were taking antihypertensive agents. The majority of them were enrolled from primary care hospitals (81%). In the nonmedicated group, the prevalence of white-coat and masked HT was 25.7% and 7.0%, respectively. Among the treated patients, the HT with white-coat effect was found in 23.3% while 46.7% had uncontrolled HBP (a combination of the masked uncontrolled HT (9.6%) and sustained HT (37.1%)). In the medicated older subgroup (n = 487), uncontrolled HBP was more prevalent in male than in female (53.6% vs. 42.4%, p=0.013). CONCLUSIONS: This is the first nationwide study in Thailand to examine the prevalence of HT subtypes. Almost one-fourth had white-coat HT or HT with white-coat effect. Approximately half of the treated patients especially in the older males had uncontrolled HBP requiring more intensive interventions. These results emphasize the role of HBP monitoring for appropriate HT diagnosis and management. The cost-effectiveness of utilizing THAI HBPM in routine practice needs to be examined in the future study.

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.

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.