There have been notable shifts in the epidemiology, microbiologic characteristics, and treatment results for patients with infective endocarditis in developed nations. Rheumatic heart disease (RHD), previously regarded as the primary risk factor for infective endocarditis (IE), is increasingly being overshadowed by emerging factors. These include invasive vascular interventions (IVI), the presence of prosthetic cardiac devices, various implants, and surgical correction procedures for congenital cardiac defects.¹ In developed countries, it has been observed that as many as 30% of all cases of infective endocarditis (IE) are linked to these factors.² Acute infective endocarditis is most commonly attributed to staphylococcus aureus. The condition exhibits significant toxicity and can advance over a period of days to several weeks, leading to valvular damage and the potential for metastatic infection. Subacute infective endocarditis, typically attributed to viridians streptococci, enterococci, coagulase-negative staphylococci, or gram-negative coccobacilli, develops over a period of weeks to months, presenting with only mild toxicity and infrequently leading to metastatic infections.³This condition represents a significant complication associated with rheumatic valvular heart disease.

When examining the etiologic agents, it is important to note that many published studies face challenges due to the limited sensitivity of the bacterial culture methods employed, particularly conventional in-house blood culture techniques. Consequently, nearly 50% of infective endocarditis cases are documented as culture negative.⁴ The absence of reliable data regarding common etiologic agents and their susceptibility patterns significantly hinders the selection of appropriate empirical antibiotic treatment.

Recent research from developed nations indicates a shifting landscape in infective endocarditis. This change can be linked to advancements in diagnostic capabilities, increased life expectancy among patients with congenital and acquired valvular conditions, more proactive surgical interventions, the rise of new at-risk populations—including intravenous drug users, individuals with prosthetic heart valves, those experiencing nosocomial bacteremia, and patients with degenerative heart disease—as well as a decrease in rheumatic heart disease cases.^5-7 Echocardiography has significantly enhanced the capacity to either confirm or rule out a diagnosis of infective endocarditis. Notably, it allows for the detection of vegetative lesions. Echocardiography is crucial for identifying complications associated with endocarditis, including perivalvular abscesses, aneurysms, fistulas, and ruptures of valvular leaflets, chordae, papillary muscles, or the interventricular septum.⁸

This observational study aimed to identify the microorganisms responsible for infective endocarditis and to outline the clinical profiles of patients with rheumatic heart disease within the local population of Gujarat. Additionally, it sought to assess the effectiveness of medical treatment and evaluate the prognosis of the cases studied.

Patients presenting at the Medicine Outpatient Department or Emergency Services at the Tertiary Care Teaching Institute of India, with clinical suspicions of infective endocarditis, underwent thorough investigations. The instances of rheumatic heart disease, categorised under infective endocarditis, have been selected for additional investigation. A research study was conducted involving 50 carefully chosen patients diagnosed with Rheumatic heart disease, all meeting the established criteria for infective endocarditis.

A thorough clinical history and physical examination were conducted, with particular emphasis on identifying predisposing factors and potential complications, in accordance with the established guidelines outlined in the Performa. A comprehensive hemogram, urinalysis with a focus on microscopic haematuria, chest X-ray, and EKG were conducted as standard procedure. Blood cultures were collected prior to the commencement of therapy. A comprehensive M mode and 2D echocardiographic assessment was conducted for all suspected cases, while those deemed uncertain underwent transesophageal echocardiography (TEE). Additional investigations were conducted to thoroughly document and verify complications as necessary. All patients provided informed consent, and approval from the ethics committee was secured before the study commenced.

Statistical analysis           

The collected data was systematically organised and input into a spreadsheet application (Microsoft Excel 2019) before being transferred to the data editor interface of SPSS version 19 (SPSS Inc., Chicago, Illinois, USA). Quantitative variables were characterised using means and standard deviations or medians and interquartile ranges, depending on their distribution. Qualitative variables were reported in terms of counts and percentages. The confidence level for all tests was established at 95%, while the level of significance was determined to be 5%

A study has identified 50 cases of rheumatic heart disease that meet the diagnostic criteria for infective endocarditis. The patient age range in the study spanned from 10 to 50 years, with the highest concentration of individuals falling within the 10–20-year age group. The ratio of male to female patients was observed to be 3:1. The majority of patients presented with a combination of mitral and aortic valve lesions, accounting for 46% of cases. The most frequently observed combined lesions among our patients were mitral and aortic regurgitation, accounting for 22% of cases.

Every participant in our study presented with mild to moderate grade fever, with a prevalence rate of 100%. Upon examination, nearly all patients exhibited signs of pallor. A total of 12 patients presented with altered sensorium, exhibiting either focal neurological deficits or not. All patients exhibited an audible cardiac murmur upon auscultation. Among the patients studied, 22 individuals, representing 44%, were diagnosed with congestive heart failure. Clubbing was observed in 18 patients, accounting for 36% of those with peripheral signs of infective endocarditis. No instances of Osler's nodes, Janeway lesions, or Roth's spots were observed in any of the patients. In the study cohort, 28 patients exhibited splenomegaly.

In a comprehensive analysis of 50 cases, it was found that all participants exhibited haemoglobin levels below the normal range, indicating a 100% prevalence of this condition. Notably, 6 patients were classified as severely anaemic, with haemoglobin levels dropping below 7 gm/dl. At the time of admission, 25 patients in the study group presented with a leukocyte count exceeding 10,000 cells per cubic millimetre (see Table 1). A significant majority of patients in the study group exhibited elevated ESR levels, with 94% showing this condition. A total of eight patients, representing 16%, exhibited characteristics of microscopic haematuria. In a study involving 50 patients, blood cultures yielded positive results in 14 cases. Conversely, 36 patients exhibited negative blood cultures, even after multiple sample collections and a seven-day incubation period, as detailed in Table 1. Staphylococcus aureus emerged as the most frequently isolated organism, identified in 6 out of 50 blood samples from patients. In the analysis of Staphylococcus aureus, sensitivity to aminoglycosides was observed in 4 samples, while resistance was noted in 2 samples. Oxacillin and Vancomycin are two important antibiotics used in the treatment of bacterial infections. Streptococcus viridans was isolated from the blood cultures of 4 patients, representing 8% of the samples analysed. The organism exhibited sensitivity to penicillin G and aminoglycosides. A total of 46 out of 50 patients exhibited vegetations as confirmed by echocardiography, representing a notable 92% prevalence rate. The aortic valve was the most frequently affected, observed in 15 patients, accounting for 30% of cases. The mitral valve was implicated in 15 patients, representing 30% of the cases. Among these, the majority of patients exhibit vegetations on the anterior mitral leaflet (AML).

All patients received treatment based on empirical evidence after five blood samples were sent for culture analysis. In a clinical setting, treatment commenced with Penicillin G injections administered at a dosage of 12 to 18 million IU, divided into six doses. Additionally, gentamicin was given at a rate of 3 to 5 mg/kg/day, also divided into three doses, for a cohort of 40 patients, representing 80% of the study group. Twenty patients showed a positive response to treatment, achieving afebrile status within eight days, with the treatment duration limited to just two weeks. Ten of these patients achieved afebrile status after ten days of treatment, during which injection penicillin G was administered. This therapy was extended for an additional two weeks, culminating in a total treatment duration of four weeks. A total of 10 patients, representing 20%, were initiated on an intravenous dose of 2 grammes of ceftriaxone once daily.

Table 1: Findings from various investigations in patients diagnosed with infective endocarditis

Recent western studies indicate a significant increase in the average age, rising from 30 to approximately 50 years over the past three decades.³ In India, the average age has largely remained consistent, with a significant portion of patients still under the age of 40. Key considerations encompass reduced life expectancy and a significant prevalence of rheumatic heart disease.⁹

The study encompassed a diverse age range, spanning from 10 to 50 years. Notably, the highest concentration of participants fell within the 10 to 20 years age bracket, while the overall mean age recorded was 27 years. The study comprised a total of 37 male patients and 13 female patients. This statistic aligns with findings from other studies conducted in India.⁹ Tariq and colleagues, in their 2004 study, reported a mean age of 24 years.A 2015 report from the same group indicated a shift in the mean age to 42 years, which is in proximity to the mean age of patients observed in this study, recorded at 34.5 years.11 The management of many of these diseases frequently necessitates sophisticated medical interventions, including cardiac implants and invasive vascular procedures. This approach may expose patients to endocarditis risk factors akin to those prevalent in contemporary society. Nonetheless, further research is essential to confirm this shift.

The current study observed that lone aortic valve involvement occurred in 30% of cases, while combined involvement of both the aortic and mitral valves was identified in 48% of cases. In 20% of the cases examined, an isolated mitral valve lesion was identified. The findings align with both Indian and Western studies. Alvular thickening measuring was frequently observed in individuals diagnosed with rheumatic carditis.^6,7 The thickening of the valve observed during the initial episode of rheumatic carditis could be attributed to valvulitis or may indicate the impact of previously unnoticed episodes of rheumatic fever.

This study found that the source of infection was identified in just 20% of cases, a finding that aligns with observations made by other researchers.¹² In our study, 22 patients, representing 44%, had already received a diagnosis of rheumatic heart disease, while only 10 patients, or 20%, were adhering to long-acting penicillin prophylaxis. This indicates a lack of adherence among our patients.

Fever stands out as a primary indicator of infective endocarditis. In our study, every patient exhibited mild to moderate grade fever, with a prevalence of 100%. The recorded fever ranged from 41.2 to 100% in various studies. Moderate normocytic normochromic anaemia frequently presents as a notable characteristic in cases of infective endocarditis. This aligns with multiple studies conducted in India.^{2, 4, 5}

The current study revealed that haemoglobin levels were low across all patients, with 88% experiencing mild to moderate anaemia. This finding aligns with the results of several studies conducted in India. The occurrence of leucocytosis is reported to range between 39% and 58% across different studies.¹³

This study found that blood culture was positive in 30% of cases, while Indian studies report a range of blood culture positivity from 21% to 97%. In the realm of Western series, the levels of positivity fluctuate between 73% and 97%. The current study identified Staphylococcus aureus as the predominant organism, isolated in 12% of cases. In the study, Streptococcus viridans was identified in 8% of the cases, while coagulase-negative staphylococcus and Acinetobacter were found in two cases, accounting for 4% of the isolates. The findings in these studies diverge from those observed in several Western studies, yet they align with certain Indian research outcomes.¹⁴ The results align closely with those reported by other research teams both nationally and internationally.^15-19. A systematic review by Slipczuk et al. revealed a global rise in the percentages of staphylococcal and enterococcal infective endocarditis over the past decade.⁸ In developing regions, Streptococci appear to be the leading cause, while in many western and developed areas, S. aureus is reported as the primary agent responsible for infective endocarditis.²⁰ The challenges in identifying the causative microorganism of infective endocarditis using traditional methods are linked to elevated rates of blood culture-negative endocarditis. The identification of microorganisms relies on the use of molecular and serological methods.²¹

The current study revealed that vegetations were observed in 92% of the cases examined. The current investigation revealed that vegetations were predominantly located on the aortic and mitral valves. The aortic valve was implicated in 60% of the cases, while the mitral valve was involved in 30% of the instances. Various studies conducted in India have demonstrated similar results.^{22, 23}

The study faced certain limitations, notably a small sample size and the use of convenient sampling methods. The limited sample size hindered the ability to draw statistically significant conclusions. Nonetheless, the limited prevalence and brief duration of this study hindered the possibility of obtaining a larger sample size.

The most prevalent manifestation includes fever along with constitutional symptoms. Mild to moderate anaemia, leucocytosis, and elevated ESR are frequently observed conditions. In our study, Staphylococcus emerged as the leading causative agent. The success of endocarditis treatment significantly improved when appropriate antibiotics were initiated following culture and sensitivity testing, as opposed to relying on empirical treatment methods. IE manifests with a range of nonspecific symptoms and clinical findings. Given the rise in health-related procedures, it is essential to consider the diagnosis in patients, regardless of whether they present risk factors. Understanding the local epidemiology and prevalence of infectious endocarditis is essential.

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