This study included 60 patients with FMF; 32 (53.3%) were males and 28 (46.7%) females. Mean ±SD age of the patients was 10.43 ± 3.472 years. The control group included 40 age and gender-matched apparently healthy children, 21 (52.5%) were males and 19 (47.5%) females. Their mean age was 12.61 ± 2.32.
Patients had a mean age of diagnosis 6.13 ± 2.771 years. Positive family history of FMF was found in 36.7% of patients. The number of FMF attacks per year at disease diagnosis were 29.58 ± 16.939 (range: 3– 60) and decreased to 6.72 ± 5.149 (range: 0 – 20) at time of study.
Systolic and diastolic blood pressures and BMI were within normal range and no statistically significant difference between cases and controls (Table 1). Fever and abdominal pain were present in all patients (100%) followed by arthritis (48.3%). Nearly half the patients had moderated disease severity (51%). Most of the patients (96.7%) were good responders to therapy. Ten patients (16.66%) had long QTc ranging between 464.1 and 482.2 msec.
Demographic data, clinical manifestations, laboratory parameters and data about colchicine therapy are shown in (Table 1).
Valvular involvement was detected by conventional echocardiography in 16.66% of patients in the form of mild MR (6.66%), trivial MR (8.33%), and mild AR (1.7%).
There was no statistically significant difference between patients and controls regarding echocardiographic diameters and contractility. Fraction shortening and ejection fraction were close in patients and control (38.35 ± 4.157 versus 39.83 ± 4.132%, p value 0.085 and 68.82 ± 5.357 vs 69.33 ± 4.190%, p value 0.597 respectively) (Table 2). On the other hand, Tpe and Pd were longer in the patients with no statistical significance (p value 0.07 and 0.135 respectively). Furthermore, statistically significant longer QTc, JTc and Tpe/QTc ratio were found in cases compared with controls (p value 0.023, 0.054 and 0.022 respectively) (Table 2). On the other hand, we didn’t find significant differences in QT, JT intervals, corrected JT (JTc), QT interval dispersion (QTd), JT dispersion (JTd) and peak to end T wave (Tpe) between patients and control.
Patients were divided into two groups according to the presence of amyloidosis. Pd was significantly higher in patients with amyloidosis (p value 0.03), while the rest of ECG parameters didn’t show any difference between the two groups (Table 3).
Fifteen patients (25%) had borderline QTc ranging between 441.1 and 457.4 milliseconds; mean ±SD age was 10.86 ±4.15 years.
We presented the correlation between different ECG parameters of the patients with their demographic data, clinical manifestations, disease severity score and colchicine therapy (Table 4). We found positive correlation between QT and JT with the age at time of study (p-value 0.022, 0.014 respectively), disease duration (p-value 0.000) and duration of attack in hours at time of study (p-value 0.042, 0.012 respectively). Pd correlated negatively with the child’s age at time of study (p-value 0.007), at disease onset (p-value 0.018) and at diagnosis (p-value 0.019). On the other hand, it correlated positively with number of attacks per month (p-value 0.022) and per year at time of study (p-value 0.035), erysipelas like erythema (p-value 0.010) and severity score (p-value 0.05).
Dose of colchicine therapy at time of study correlated with JT interval (p-value 0.028). Furthermore, JT interval, together with QT intervals, correlated with duration of colchicine treatment (p-value 0.00). Furthermore, Tpe/QTc ratio correlated with FMF50 score (p-value 0.036) (Table 4).
There was positive correlation between QTc interval and 24 hours proteinuria (p-value 0.039). Furthermore, QT and JT intervals correlated with fibrinogen (p-value 0.004 and 0.002 respectively) (Table 5).