Table 3.

The ECG's characteristics

Code	ECG changes	No. of rejection	Outcomes or notes
E 1	The frequency content of the ST section decreased from 10 to 30 Hz, and the frequency content of the QRS varied from 60 to 150 Hz.	16 Patients	For the noninvasive diagnosis of acute cardiac rejection after cardiac transplantation, FFT of surface ECGs is encouraging. The mechanism of improvements and the future application of this approach for persistent rejection assessment continue to be assessed.
E 2	In detecting rejection, the root‐mean‐square voltage of the 70‐Hz high pass filtered QRS complex was found to be the most reliable component.	20 Patients	In the control of heart transplant rejection, the signal‐averaged ECG is useful. Compared with the time‐domain method, frequency domain analysis of the QRS complex would not improve the technique's precision.
E 3	Depression of the ST section in the precordial segments (mostly V3‐V6) and the limb leads.	‐	Dipyridamole electrocardiography in the early post‐transplantation era is practical, secure, and affordable, with the potential for noninvasive monitoring of transplantation rejection.
E 4	In the AR group, the QTc dispersion was 40 ± 17 ms.	31 Patients	Proposals for the use of QTc dispersion for diagnosing AR in HT patients are not confirmed by the findings of this review.
E 5	Longer PR interval RBBB ECG changes.	3 Patients	Near observation of new RBBB growth at 1‐year post‐HT, associated with a higher rate of new‐onset graft rejection, can be helpful in detecting high‐risk graft rejection patients.
E 6	Disappearance of R waves in I, aVL, and prolongation of wider QRS duration PR intervals and deeper S waves in V5,6 in I, II, aVF deep S wave, poor R progression in all anterior precordial leads, marked PR interval prolongation, and V4‐6 deeper S wave. Also found were ST depression and T wave inversion in I, aVL, and V2‐6.	2 Patients	While no rejection‐specific ECG changes have been reported so far, the above‐described changes that may represent actual hemodynamic anomalies may be a diagnostic tool for rejection.
E 7	Important changes in the high‐frequency components (between 50 and 110 Hz) of the QRS complex and significant reductions in the low‐frequency components (between 10 and 30 Hz).	‐	During acute rejection, improvements in the ECG properties of transplanted hearts were observed, with improvements in intraarticular and auriculoventricuir conduction and decreases in QRS voltage amplitude. These experimental findings should be considered in the development of new methods for detecting cardiac allograft rejection ECGs.
E 8	An expanded QTC interval in recipients of a heart transplant is linked to acute allograft rejection and death.	‐	In heart transplant recipients, a noninvasive measure of early allograft rejection has the ability to reduce the number and severity of rejection episodes by reducing the time and cost of monitoring of rejection and shortening the time to identification of rejection. In addition, other ECG parameters important to noninvasive allograft rejection monitoring must be identified to achieve the objectives of the current study and may provide evidence for a randomized controlled trial to assess the feasibility and cost‐effectiveness of this form of noninvasive ECG monitoring as compared with normal EMB surveillance.
E 9	A decrease in the summed QRS voltage in the anterior chest leads and a turn to the right in the QRS frontal vector was also seen in humans and nonspecific repolarization shifts were also seen and drops in the evoked T wave amplitude.	18 Patients	At the time of transplantation, QT‐driven rate‐responsive units can be implanted with periodic interrogation of these units, theoretically abrogating the need for endomyocardial biopsy.
E 10	Higher frequency QRS voltages.	20 Patients	The study shows the relative loss of high‐frequency SA‐ECG components in cardiac transplant rejection patients and suggests that SA‐ECG may be useful for noninvasive cardiac transplant rejection assessment.
E 11	ECG voltage amplitude (IMEG) seems to follow a "focal pattern" similar to the histology.	40 Patients	‐
E 12	Important changes in the length of QRS (p < .001), QT (p = .009), QTc (p = .003), and PR (p = .03) cycles, as well as increased odds of development of right bundle block branch (p = .002) and fascicular block (p = .009).	12 Patients	Electrocardiographic changes following transplant surgery have been linked with mild to serious acute allograft rejection.
E 13	Significant decreases in QRS voltage.	10 Patients	These results suggest that in the estimation of cardiac rejection, QRS voltage is of highly limited benefit in patients treated with low‐dose triple immunotherapy.
E 14	QRS reduction in the standard ECG.	13 Patients	A useful screening tool for mild to extreme acute rejection is QRS voltage reduction in a localized region measured by BSPM.
E 15	Prolongation in both QTc time and QTc dispersion of >40 ms.	100 Patients	ECGs are routinely conducted, QTc time measurements and QTc dispersion can be accurately used to detect acute rejection early after heart transplantation.
E 16	A significantly larger high frequency QRS complex component (50–110 Hz).	19 Patients	ECG for the diagnosis of acute allograft rejection is a useful noninvasive technique.
E 17	The QRS complex's peak‐to‐peak amplitudes and heart rate are substantially reduced, the power of and the LF is significantly increased.	‐	A successful noninvasive marker for early detection of cardiac allograft rejection is heart rate variability study. A responsive means of measuring the effects of immunosuppressive therapy can also be given by this procedure.
E 18	Increased QT dispersion in patients with rejection.	41	No statistical significance of QTc−d and severity of rejection. QTc−d should not be considered a sensitive marker for OHT rejection.