Ventricular Arrhythmias

Outcome of life-threatening arrhythmias among patients presenting in an emergency setting at a tertiary hospital in Accra-Ghana

Background

Management of life-threatening arrhythmia can be incredibly challenging in advanced health systems. In sub-Saharan Africa (SSA), this is likely more challenging because of weak pre-hospital and in-hospital critical care systems. Little is known about life-threatening arrhythmia and their outcomes in SSA. The aim of this study was to examine the types and outcomes of arrhythmias among haemodynamically unstable patients presenting at a tertiary hospital in Accra-Ghana.

Method

This was a retrospective case series study conducted at the Korle-Bu Teaching Hospital (KBTH), Accra-Ghana. Medical records of patients who presented with or developed haemodynamically unstable arrhythmias within 24h of admission from January 2018 to December 2020 were reviewed. The demographic characteristics and clinical data including outcomes of patients were collected. Descriptive statistics were used and results presented in frequency tables.

Results

A total of 42 patients with life-threatening arrhythmias were included. Haemodynamically unstable tachyarrhythmias were the most common arrhythmias found among the patients (66.7%). Approximately 52% of patients had structural heart diseases whereas 26.2% had no apparent underlying cause or predisposing factor. Cardioversion (52.4%), commonly electrical (63.6%), and transvenous pacemaker implantation (23.8%) were the common initial interventions. The majority of the patients (88.1%) survived and were discharged home.

Conclusion

Tachyarrhythmias are the most common haemodynamically unstable arrhythmias seen among patients presenting emergently in a leading tertiary hospital in Ghana. A high survival rate was observed and cannot be extrapolated to other healthcare settings in sub-Saharan Africa with limited resources to manage these clinical entities.

The Impact of Fine Particulate Matter 2.5 on the Cardiovascular System: A Review of the Invisible Killer

Air pollution exerts several deleterious effects on the cardiovascular system, with cardiovascular disease (CVD) accounting for 80% of all premature deaths caused by air pollution. Short-term exposure to particulate matter 2.5 (PM_2.5) leads to acute CVD-associated deaths and nonfatal events, whereas long-term exposure increases CVD-associated risk of death and reduces longevity. Here, we summarize published data illustrating how PM_2.5 may impact the cardiovascular system to provide information on the mechanisms by which it may contribute to CVDs. We provide an overview of PM_2.5, its associated health risks, global statistics, mechanistic underpinnings related to mitochondria, and hazardous biological effects. We elaborate on the association between PM_2.5 exposure and CVD development and examine preventive PM_2.5 exposure measures and future strategies for combating PM_2.5-related adverse health effects. The insights gained can provide critical guidelines for preventing pollution-related CVDs through governmental, societal, and personal measures, thereby benefitting humanity and slowing climate change.

Primary hyperparathyroidism associated with acquired long QT interval and ventricular tachycardia

SUMMARY

We present a 54-year-old patient admitted to the emergency department due to loss of consciousness. The initial ECG registered monomorphic ventricular extrasystoles and prolonged QT interval (QT corrected (QTc) >500 ms). Sustained ventricular tachycardia (VT) was registered on 24-h Holter ECG monitoring, which clinically was presented as a crisis of consciousness. Coronary angiography and other visualization methods were normal. Implantable cardioverter-defibrillator (ICD) implantation was planned for the purpose of secondary prevention of sudden cardiac death (SCD). Laboratory and hormonal analyzes revealed primary hyperparathyroidism (PHPT), chronic kidney disease, and hypokalemia. Neck ultrasound showed a 25 mm, sharply outlined homogenous tumor mass which was separated from thyroid gland (TG) and exerted a mild impression on lower parts of the left lobe. Dual wash technetium-99m sestamibi parathyroid scintigraphy with single-photon emission CT (SPECT)/CT also showed the uptake of tracer behind the lower half of the left lobe of the TG. Surgical treatment, lower left parathyroidectomy, was performed, and pathohistological analysis verified parathyroid adenoma. The patient was rhythmically and hemodynamically stable for 7 days after surgery, without additional complaints, and was discharged from the hospital. Timely diagnosis of PHPT, correct assessment and surgical treatment, did not lead our patient to unnecessary ICD implantation. Our case suggests an additional intertwining of electrolyte disorders and ventricular arrhythmias in PHPT and more importantly emphasizes the need for caution when indicating ICD, even in patients with the most serious life-threatening arrhythmias.

LEARNING POINTS

Electrolyte abnormalities in PHPT can have highly malignant consequences, and the occurrence of hypokalemia in the presence of hypercalcemia is underestimated in PHPT, and the consequences can be life-threatening. Although hypercalcemia causes shortened QT interval, concomitant severe hypokalemia may overcome hypercalcemia and prolong QT interval, even in the absence of structural heart disease or LQTS. Timely diagnosis of PHPT, correct assessment and surgical treatment, do not lead to unnecessary ICD implantation.

Coronary vasospasm as an etiology of recurrent ventricular fibrillation in the absence of coronary artery disease: a case report

Background: Vasospastic angina (VA), or Prinzmetal’s angina, is characterized by symptoms of coronary angina caused by coronary vasospasm, usually in the absence of atherosclerotic changes. It typically presents with chest pain, which can be accompanied by transient electrocardiographic changes, if visualized during the attack. It can also rarely present with severe manifestations of acute myocardial angina, ventricular fibrillation, or cardiac arrest.

Case presentation: We present a case of a 50-year-old Caucasian male who initially presented to the hospital with chest pain and was diagnosed with VA. Later, he was brought to the hospital by emergency medical services later with ventricular fibrillation, despite normal coronary anatomy on angiogram. He was managed with placement of an intra–cardiac defibrillator (ICD) for secondary prevention. The patient continued to have recurrent episodes of ventricular fibrillation with associated ICD shocks, and had multiple admissions to the hospital with similar presentations. Symptoms and arrhythmia improved after optimizing antianginal therapy.

Conclusions: Ventricular fibrillation can be an uncommon but severe manifestation during VA crises. In cases with normal coronary vasculature, it is important to recognize VA as a cause of recurrent ventricular fibrillation in order to optimize medical management for prevention of fatal arrhythmias.

Correlation of Prolonged Corrected QT Interval With Ventricular Arrhythmias and In-Hospital Mortality Among ST-Elevation Myocardial Infarction Patients: A Mystique or Lucidity?

Background Ventricular arrhythmias (VAs) are a frequent cause of cardiovascular mortality, especially in developing countries. Prolongation of corrected QT (QTc) interval predisposes patients to life-threatening VAs. Our study aims to assess the correlation of prolonged QTc interval with VAs and in-hospital mortality among ST-elevation myocardial infarction (STEMI) patients.  Methods This cross-sectional study analyzed the data from 40 patients with a confirmed diagnosis of STEMI and prolonged QTc interval. The patients were evaluated for several characteristics including their electrocardiography (ECG) findings. The frequency of in-hospital mortality and VAs developed after admission were recorded. Spearman correlation was used to assess the correlation of prolonged QTc interval with VAs and in-hospital mortality. Results Out of 40 cases, 30 patients were males and 10 were females with a mean age hovering at 52.95 ± 10.65 years. The mean QTc interval of our patients was 512.02 ± 49.74 milliseconds (ms). A total of 11 (27.5%) patients developed VAs while 14 (35%) of the patients succumbed to the disease complications. Spearman correlation showed a strong significant positive correlation of QTc interval with VAs (rho = 0.658, p < 0.001) and in-hospital mortality (rho = 0.314, p = 0.04). Conclusion Prolonged QTc interval is positively correlated with VAs and in-hospital mortality among STEMI patients. These patients should be regularly monitored and must be managed with caution as they have increased chances to develop VAs and in-hospital mortality. There is an utmost need for curation of guidelines that aid in risk stratification and appropriate management of such patients.

Long-Term Particulate Matter Exposure and Incidence of Arrhythmias: A Cohort Study

Background Studies have shown that short-term exposure to air pollution is associated with cardiac arrhythmia hospitalization and mortality. However, the relationship between long-term particulate matter air pollution and arrhythmias is still unclear. We evaluate the prospective association between particulate matter (PM) air pollution and the risk of incident arrhythmia and its subtypes. Methods and Results Participants were drawn from a prospective cohort study of 178 780 men and women who attended regular health screening exams in Seoul and Suwon, South Korea, from 2002 to 2016. Exposure to PM with an aerodynamic diameter of ≤10 and ≤2.5 μm (PM₁₀ and PM_2.5, respectively) was estimated using a land-use regression model. The associations between long-term PM air pollution and arrhythmia were examined using pooled logistic regression models with time-varying exposure and covariables. In the fully adjusted model, the odds ratios (ORs) for any arrhythmia associated with a 10 μg/m³ increase in 12-, 36-, and 60-month PM₁₀ exposure were 1.15 (1.09, 1.21), 1.12 (1.06, 1.18), and 1.14 (1.08, 1.20), respectively. The ORs with a 10 μg/m³ increase in 12- and 36-month PM_2.5 exposure were 1.27 (1.15, 1.40) and 1.10 (0.99, 1.23). PM₁₀ was associated with increased risk of incident bradycardia and premature atrial contraction. PM_2.5 was associated with increased risk of incident bradycardia and right bundle-branch block. Conclusions In this large cohort study, long-term exposure to outdoor PM air pollution was associated with increased risk of arrhythmia. Our findings indicate that PM air pollution may be a contributor to cardiac arrhythmia in the general population.

Phase Entrainment of Induced Ventricular Fibrillation: A Human Feasibility and Proof of Concept Study

Cardioversion and defibrillation by a single high energy shock applied by myocardial or body surface electrodes is painful, causes long term tissue damage, and is associated with worsening long term outcomes, but is almost always required for treatment of ventricular fibrillation . As a initial step towards developing methods that can terminate ventricular arrhythmias painlessly, we aim to determine if pacing stimuli at a rate of 5/s applied via an implantable cardiac defibrillator (ICD) can modify human ventricular fibrillation. In 8 patients undergoing defibrillation testing of a new/exchanged intracardiac defibrillator, five seconds of pacing at five stimuli per second was applied during the 10-20 seconds of induced ventricular fibrillation before the defibrillation shock was automatically applied, and the cardiac electrograms recorded and analyzed. The high frequency pacing did not entrain the ventricular fibrillation, but altered the dominant frequency in all 8 patients, and modulated the phase computed via the Hilbert Transform, in four of the patients. In this pilot study we demonstrate that high frequency pacing applied via ICD electrodes during VF can alter the dominant frequency and modulate the probability density of the phase of the electrogram of the ventricular fibrillation.