Treatment Effects of Switching to Faricimab in Eyes with Diabetic Macular Edema Refractory to Aflibercept.

Background and Objectives: Faricimab is a vascular endothelial growth factor A and angiopoietin-2 bispecific antibody. It is a novel therapeutic approach distinct from previous anti-vascular endothelial growth factor agents. This study aimed to evaluate the efficacy of switching from aflibercept to faricimab in the treatment of diabetic macular edema (DME) refractory to aflibercept, with a specific focus on the resolution of macular edema. Materials and Methods: The medical records of 29 eyes of 21 patients with DME that were refractory to intravitreal injections of aflibercept (IVAs) and who had completed the clinical follow-up of at least four intravitreal injections of faricimab (IVFs) were reviewed. The central retinal thickness (CRT), best-corrected visual acuity (BCVA), and the mean period (weeks) until the next injection were measured after the second-to-last IVA, first-to-last IVA, last IVA, and first to fourth IVFs following the transition to IVF. Results: The mean time from the first IVF to the assessment of effectiveness was significantly shorter than the time to the last IVA; however, no significant difference was found in the time from the second, third, and fourth IVFs to the assessment. The mean CRTs after the first and second IVFs were not significantly different from the CRT after the last IVA, but the mean CRT after the third and fourth IVFs was significantly thinner than that after the last IVA (p = 0.0025 and p = 0.0076, respectively). The mean BCVAs after the third and fourth IVFs significantly improved compared with that after the last IVA (p = 0.0050 and p = 0.0052, respectively). Conclusions: When switching the treatment to IVF for eyes with IVA-resistant DME, better treatment outcomes are achieved if IVF is performed three or more times.

Comparisons of surgical outcomes after epiretinal membrane peeling in the myopic eyes with long to that with normal axial length.

PURPOSE: To compare the outcomes of vitrectomy with removal of an idiopathic epiretinal membrane (ERM) in the myopic eyes with long axial length (AL) to that in the eyes with normal AL. METHODS: This was a retrospective, observational, case-control study. Fifty-six eyes of 56 patients with an idiopathic ERM were studied. Twenty-eight of these eyes had an axial length longer than 26.0 mm (Group A), and the other 28 eyes had axial lengths < 26.0 mm (Group B). The age and visual acuity of the two groups were not significantly different. All subjects were treated by vitrectomy and peeling of the ERM with a 25- or 27-gauge system. The postoperative best-corrected visual acuity (BCVA) and optical coherence tomographic findings were determined at 3 and 6 months postoperatively. RESULTS: The mean BCVA improved from 0.35 ± 0.25 to 0.15 ± 0.25 logMAR units in the eyes with the long AL and from 0.35 ± 0.25 to 0.10 ± 0.21 logMAR units in the eyes with normal AL at 6 months postoperatively (both P < 0.001). The postoperative BCVA was not significantly different between the two groups at 6 months (P = 0.221). The central macula was thinner in the eyes of Group A than Group B (P < 0.001). The restorations of the ellipsoid zone and the external limiting membrane were observed in both groups, but the interdigitation zone was less frequently restored in Group A (P < 0.001). CONCLUSIONS: Vitrectomy with the removal of the epiretinal membrane is effective in attaining a good BCVA even in the myopic eyes with long AL.

Refractive errors after sutureless intrascleral fixation of intraocular lens.

PURPOSE: To determine the difference between the attempted and the achieved postoperative refractive error after sutureless intrascleral fixation of the haptics of an implanted intraocular lens (IOL). PATIENTS AND METHODS: This was a retrospective study of the medical charts of patients who had undergone sutureless intrascleral fixation of an IOL. The IOLs were fixed by inserting the haptics into scleral tunnels with or without flanges. The differences between the attempted and achieved postoperative refractive error (spherical equivalent) were determined. The relationships between the surgical options and the differences of the refractive error and degree of astigmatism were also determined. RESULTS: Two hundred and twenty-three eyes were studied. There was a myopic shift of - 0.38 ± 1.13 diopters (D). The mean of the differences between the achieved postoperative and the attempted refractive error was 0.89 ± 0.79 D. The achieved refractive error was significantly correlated with the attempted refractive error (P < 0.001, R2 = 0.631). The surgical procedures selected were not significantly associated with the differences between the attempted and achieved refractive error. The size of sclerocorneal incision and presence of sutures were significantly associated with the final degree of astigmatism (P = 0.006 and 0.008, respectively). CONCLUSIONS: The postoperative refractive error was significantly correlated with the attempted refractive error after intrascleral fixation of an IOL. The wound construction was associated with the postoperative degree of astigmatism.

Comparison of Internal Limiting Membrane Peeling and Flap Removal to Flap Insertion on Visual Outcomes in Highly Myopic Eyes with Macular-Hole Retinal Detachment.

INTRODUCTION: To compare the morphological and visual outcomes after pars plana vitrectomy (PPV) with internal limiting membrane (ILM) peeling and flap removal to that with flap insertion in eyes with myopic macular-hole retinal detachment (MHRD). METHODS: Forty-six eyes of 45 patients with MHRD were studied. Eighteen eyes were treated by PPV with ILM peeling and flap removal and 28 eyes by flap insertion, respectively. The baseline characteristics and postoperative findings were compared between the 2 groups. RESULTS: The average age of the cases was 70.0 ± 8.5 years. The best-corrected visual acuity (BCVA) improved, from 1.51 ± 0.14 to 1.31 ± 0.20 logMAR units in the flap removal group, and from 1.20 ± 0.10 to 0.88 ± 0.10 logMAR units in the flap insertion group (p = 0.049). A significantly larger number of MHs were closed in the flap insertion group (96 vs. 50% in the removed group; p < 0.001). Restoration of the ellipsoid zone (EZ) and external limiting membrane (ELM) was also better in the flap insertion group than in the flap removal group (EZ 14 vs. 6%, p = 0.003; ELM 36 vs. 6%, p < 0.001). DISCUSSION: The technique of ILM peeling with flap insertion is more effective in closing the MH, and results in better BCVA and better restoration of the outer retinal microstructures than flap removal.

Improvements of Retinal Sensitivity after Intravitreal Injection of Aflibercept in Eyes with Neovascular Age-Related Macular Degeneration with or without Polypoidal Choroidal Vasculopathy.

PURPOSE: We aim to determine the effects of intravitreal aflibercept (IVA) on the mean sensitivity (MS) of the central retina, best-corrected visual acuity (BCVA), and central foveal thickness (CFT) in eyes with neovascular age-related macular degeneration (nAMD) with or without polypoidal choroidal vasculopathy (PCV). METHODS: This was a prospective, interventional study. All eyes were treatment-naive with nAMD with or without PCV. Each eye received 3 monthly IVA injections followed by an IVA injection every 2 months for 12 months. The primary outcome was the change in the MS within the central 2°. The secondary outcomes were the changes in BCVA, CFT, greatest linear dimension (GLD), and percentage of eyes with a dry macula. RESULTS: Thirty-seven eyes of 37 patients were studied. A significant improvement of the MS (dB) was observed +4.9 ± 4.6 dB (mean ± standard deviation) at 3 M (p < 0.001), +5.5 ± 4.9 dB at 6 (p < 0.001), and +7.0 ± 3.4 dB at 12 M (p < 0.001) compared to the baseline in all eyes. The MS of the eyes with non-PCV was not significantly different from that of eyes with PCV (p = 1.00, 1.00, 1.00, and 0.76 at baseline, 3, 6, and 12 M, respectively). The MS of 11 patients whose BCVA remained unchanged was significantly improved by +6.5 ± 2.8 dB at 3 M (p < 0.001), +6.1 ± 4.3 dB at 6 M (p < 0.001), and +6.4 ± 4.8 dB at 12 M (p = 0.003) compared to the baseline. The mean BCVA was significantly improved from the baseline to 3 M (p < 0.001), 6 M (p = 0.027), and 12 M (p = 0.003) in all eyes. The BCVA was improved or maintained in 97% of the patients at 12 M. The mean CFT and GLD were significantly reduced at 12 M (p < 0.001). Twenty-two eyes (71%) had a dry macula at 12 M. CONCLUSIONS: IVA administered by a fixed dosing regimen led to significant improvements of the central MS, BCVA, and macular morphology at 1 year in eyes with nAMD with or without PCV. These results were not significantly different between eyes with non-PCV and with PCV. The improvements of the MS of the retina of the central 2° in a subgroup whose BCVA remained unchanged through the 12-month experimental period was also significant. We conclude that the MS of the central 2° might be a better marker than the BCVA in determining the effectiveness of IVA treatments and might be helpful in determining early effects on the retina before BCVA changes can be detected.

Surgical outcomes of vitrectomy for breakthrough vitreous hemorrhage in eyes with exudative age-related macular degeneration.

PURPOSE: To report the outcomes of pars plana vitrectomy in cases with breakthrough vitreous hemorrhage (VH) secondary to exudative age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy. We also investigated the relationship between the preoperative b-mode ultrasonographic findings and the postoperative visual acuity to determine if the ultrasonographic findings can predict the surgical outcome after pars plana vitrectomy. METHODS: This was a retrospective, interventional, case series. Twenty eyes of 20 patients were studied. The associations between the pre- and intraoperative factors and the final best-corrected visual acuity (BCVA) were determined. Recombinant tissue-plasminogen activator (tPA) was used in cases with massive hemorrhagic retinal detachment. RESULTS: Ten eyes with polypoidal choroidal vasculopathy (PCV), two eyes with choroidal neovascularization (CNV), and eight eyes with an unknown type of AMD were studied. The mean BCVA was 0.73 ± 0.57 logarithm of the minimum angle of resolution (logMAR) units before developing the VH, 2.25 ± 0.45 logMAR units before the surgery, and 1.52 ± 0.87 logMAR units after the surgery. The BCVA improved significantly after the surgery (P = 0.004) but was significantly worse than that before developing the VH (P = 0.012). The cases of PCV had better final BCVA than cases of CNV (P = 0.043, Mann-Whitney test). The preoperative presence of a subretinal elevation at the macula detected by ultrasonography was significantly associated with a poorer final BCVA (P = 0.031). CONCLUSIONS: Vitrectomy significantly improved visual function in the eyes with VH associated with exudative AMD. The eyes with PCV and no macular subretinal elevation on ultrasonography had a better visual prognosis.

Non-paraneoplastic autoimmune retinopathy that developed in fellow eye 10 years after onset in first eye: a case report.

BACKGROUND: Evidence-based criteria for the treatment of autoimmune retinopathy (AIR) have not been established. The pathology and clinical features of each antibody causing AIR, and its long-term course are still undetermined. We report our findings in a case of non-paraneoplastic AIR (npAIR) that developed in the fellow eye 10 years after the onset in the first eye. CASE PRESENTATION: Our patient had photophobia in both eyes and a rapidly progressing visual field defect in his right eye at the initial examination. He was diagnosed with non-paraneoplastic AIR based on the clinical findings and immunoblot analyses for anti-retinal antibodies, and he was treated with steroids. Ten years later, a visual field defect developed in the fellow eye, and a diagnosis of npAIR was made. Immunoblot analyses were positive for anti-α-enolase antibodies. He was treated with steroids, immunosuppressants, and plasma exchange. However, the response to the treatment was poor and both eyes eventually became blind. CONCLUSIONS: As best we know, this is the first case report of npAIR that developed in the fellow eye over 10 years after the development in the first eye. Long-term follow-up and a search for tumor lesions are necessary in cases of npAIR. Further understanding of the long-term course of AIR can contribute to an understanding of the pathology and treatment of npAIR.

Reduction of Optic Disc Oedema by Bortezomib and Dexamethasone Followed by Autologous Peripheral Blood Stem Cell Transplantation in Patient with POEMS Syndrome.

The authors present findings in a 39-year-old man with polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes (POEMS) syndrome with bilateral optic disc oedema. He was successfully treated with bortezomib and dexamethasone followed by autologous peripheral blood stem cell transplantation. The peripapillary retinal thickness was reduced in the optical coherence tomographic (OCT) images along with a decrease of the serum vascular endothelial growth factor (VEGF) levels. The authors recommend OCT to monitor the changes in the signs of POEMS syndrome after treatments.

Transient receptor potential ankyrin 1 in spinal cord dorsal horn is involved in neuropathic pain in nerve root constriction rats.

BACKGROUND: Lumbar radicular pain is categorized as a type of neuropathic pain, but its pathophysiological mechanisms are not fully understood. The substantia gelatinosa (SG) in the spinal cord dorsal horn receives primary afferent inputs and is considered to be a therapeutic target for treating neuropathic pain. In vivo patch-clamp recording is a useful procedure for analyzing the functional properties of synaptic transmission in SG neurons. Transient receptor potential ankyrin 1 (TRPA1) has been widely identified in the central and peripheral nervous systems, such as in the peripheral nociceptor, dorsal root ganglion, and spinal cord dorsal horn and is involved in synaptic transmission of pain. However, its functional role and mechanism of pain transmission in the spinal cord dorsal horn are not well understood. The purpose of this study was to use in vivo patch-clamp analysis to examine changes in the excitatory synaptic transmission of SG neurons treated with TRPA1 antagonist and to clarify the potential role of TRPA1 in the rat spinal cord dorsal horn. RESULTS: The rats with root constriction (RC) showed mechanical hypersensitivity, hyperalgesia, and thermal hyperalgesia. In addition, pin pricks elicited pain-related behavior even in the sham and naïve rats. These pain-related behaviors were significantly attenuated by intrathecal injection of a TRPA1 antagonist. The degrees of intrathecal injection efficacy were equivalent among the 3 groups (RC, sham, and naïve groups). In an electrophysiological study, the frequencies and amplitudes of excitatory postsynaptic currents (EPSCs) were significantly increased in the RC rats compared with those in the sham and naïve rats. Spontaneous EPSCs and evoked-EPSCs by non-noxious and noxious stimuli were significantly decreased by TRPA1 antagonist. As in the behavioral study, there were no statistically significant differences among the 3 groups. CONCLUSION: These data showed that the TRPA1 antagonist had an inhibitory effect on mechanical hypersensitivity and hyperalgesia as well as on physiological pain transmission in the spinal cord dorsal horn. This suggests that TRPA1 is consistently involved in excitatory synaptic transmission even in the physiological state and has a role in coordinating pain transmission.

Microendoscopic discectomy for far lateral lumbar disk herniation: less surgical invasiveness and minimum 2-year follow-up results.

STUDY DESIGN: A retrospective review of data collected prospectively on 24 consecutive patients who underwent microendoscopic discectomy (MED) for far lateral lumbar disk herniation. OBJECTIVE: To evaluate the level of surgical invasiveness of the procedure and clinical results with a follow-up of at least 2 years. SUMMARY OF BACKGROUND DATA: To the best of our knowledge, there have only been 2 small-size and short-term clinical studies reporting the feasibility of MED for far lateral lumbar disk herniation, despite its relatively long history. Moreover, these 2 articles did not include detailed evaluations of surgical invasiveness and did not comprise any cases with disk herniation at L5-S1, which should account for a considerable proportion of cases. METHODS: Twenty-four consecutive patients, including L5-S1 patients, who underwent MED for far lateral lumbar disk herniation participated in this study. Ninety-three consecutive patients with intracanalicular disk herniation, who underwent MED also participated as control subjects. Operative time, intraoperative blood loss, serum C-reactive protein and creatine kinase, visual analog scale, and Japanese Orthopaedic Association score were evaluated. RESULTS: The procedure was successfully performed in all cases. The operative time in patients with far lateral disk herniation (143.9 min) was significantly longer than in patients with intracanalicular disk herniation (90.2 min) (P<0.01). There were no differences between the groups in terms of intraoperative blood loss (39.6 and 40.4 mL, respectively), serum C-reactive protein level on postoperative day 3 (0.71 and 0.73 mg/dL), serum creatine kinase level on postoperative day 1 (161.8 and 225.7 IU/L), visual analog scale scores to assess surgical site pain on the first postoperative day (19.4 and 24.0 mm), or improvement rate in Japanese Orthopaedic Association score at final follow-up (76.0% and 77.0%). CONCLUSIONS: MED is a well-balanced technique which offers both reduced invasiveness and good clinical results without sacrificing reliability.

Relationship between retinal sensitivities and optical coherence tomographic findings in eyes with myopic chorioretinal atrophy.

PURPOSE: To determine whether there is a significant correlation between the retinal sensitivity and the integrity of the ellipsoid zone (EZ) of the photoreceptors in eyes with myopic chorioretinal atrophy (CRA). We also determined the significance of the correlation between the retinal sensitivity and the retinal and choroidal thicknesses. METHODS: The medical records of 10 eyes of six subjects with myopic CRA were reviewed. The integrity of the EZ was determined in the spectral-domain optical coherence tomographic (OCT) images at 37 points of six scans corresponding to the locations where the retinal sensitivities were measured by MP-3 microperimetry. The mesopic retinal sensitivities were determined within the central 16°. The significance of the correlations between the integrity of the EZ and the mesopic retinal sensitivities was determined. The relationships between the retinal and choroidal thickness and the retinal sensitivity were also determined. RESULTS: The average age of the patients was 70.0 ± 6.7 years, and the average axial length of the eye was 29.2 mm. The mesopic sensitivities at the points where the EZ was present were significantly higher than those where the EZ was absent (p < 0.01). The mesopic sensitivity was significantly correlated with the retinal thickness (p < 0.01, r = 0.30) and the choroidal thickness (p < 0.01, r = 0.23). CONCLUSIONS: The significant correlation between the mesopic retinal sensitivity and the integrity of the EZ indicates that the mesopic sensitivities can be used to assess the integrity of the photoreceptors in eyes with myopic CRA.

Long-Term Effects of Half-Time Photodynamic Therapy on Retinal Sensitivity in Eyes with Chronic Central Serous Chorioretinopathy.

The purpose of this study was to evaluate the long-term effects of half-time photodynamic therapy (PDT) on the retinal sensitivity in eyes with chronic central serous chorioretinopathy (CSC). Twenty-two eyes of 22 patients with chronic CSC were studied. PDT was applied with full-dose verteporfin and half-time laser duration. The best-corrected visual acuity (BCVA) and retinal sensitivity in the central 2 and 10 degrees were evaluated at the baseline, and at 12 and 24 months after the half-time PDT. The retinal sensitivity was determined by Macular Integrity Assessment microperimetry (MAIA, Centervue, Padova, Italy). The results showed that the mean retinal sensitivities in the central 2 and 10 degrees were significantly improved at 12 months (25.6 ± 2.79 dB, median; 26.11 dB, 25.6 ± 2.25 dB, median; 25.65 dB, respectively; P < 0.001) and at 24 months (26.3 ± 2.62 dB, median; 27.38 dB, 26.6 ± 2.21 dB, median; 27.45 dB, respectively; P < 0.001) after the treatment compared to that at the baseline (19.2 ± 3.93 dB, median; 19.34 dB, 20.9 ± 2.92 dB, median; 20.9 dB, respectively). The BCVA was also significantly improved from 0.18 ± 0.19 median; 0.15 logarithm of the minimum angle of resolution (logMAR) units at the baseline to 0.07 ± 0.15 median; 0 logMAR units at 12 months (P < 0.001) and to 0.049 ± 0.16 median; -0.039 logMAR units at 24 months (P < 0.001). We conclude that half-time PDT results in a significant improvement of the mean central retinal sensitivity for at least 24 months in eyes with chronic CSC. Thus, half-time PDT is beneficial in resolving chronic CSC for a relatively long period.

Outcomes of Vitrectomy Combined with Scleral Buckling for Eyes with Early Recurrence of Simple Rhegmatogenous Retinal Detachment Previously Treated by Pars Plana Vitrectomy.

PURPOSE: To investigate the outcomes of pars plana vitrectomy (PPV) combined with scleral buckling (SB) in treating eyes with an early recurrent rhegmatogenous retinal detachment (rRRD). METHODS: This was a retrospective, interventional case series of 21 eyes with an early rRRD treated by PPV combined with SB. The significance of the associations between the variants before the surgeries and the final best-corrected visual acuity (BCVA) was determined. RESULTS: The average age of the patients was 61.0 ± 9.6 years. A retinal reattachment was observed in 20 of 21 eyes (95.2%) after a single reoperation. The BCVA was 0.91 ± 0.90 logMAR units before the initial surgery and 0.94 ± 0.94 logMAR units before the reoperations, and it improved significantly to 0.49 ± 0.50 logMAR units after the reoperation (P = 0.016, P = 0.002, respectively). The preoperative BCVA was significantly correlated with the final BCVA (P = 0.043, r = 0.445 before the primary surgery; P < 0.001, r = 0.885 before reoperation). CONCLUSIONS: The reattachment of an early recurrent retinal detachment by PPV with SB is effective.

Suppression of Sympathetic Nerve Sprouting by Local Administration of an α-antagonist Around the Dorsal Root Ganglion in a Lumbar Radiculopathy Model.

STUDY DESIGN: Animal experimental study with intervention. OBJECTIVE: The purpose of this study was to elucidate whether local administration of an α-antagonist around the dorsal root ganglion (DRG) suppressed sympathetic nerve sprouting, from the acute to the chronic pain development phase, in a lumbar radiculopathy model using immunohistochemical methods. SUMMARY OF BACKGROUND DATA: The abnormal sympathetic-somatosensory interaction may underlie some forms of neuropathic pain. There were several reports suggesting α-antagonists are effective to treat neuropathic pain. However, its pathophysiological mechanisms remain obscure. METHODS: We used 70 male Sprague-Dawley rats. After root constriction (RC), rats received a series of three local injections of the nonselective α-antagonist phentolamine around the DRG for 3 days. There were three groups of rats: those that were injected from the day of surgery and those injected from day 4 and third group injected from day 11. The control rats were subjected to RC but equal-volume normal saline injections, and the naïve rats were not subjected to any surgical procedures. At the 14th postoperative day, the left L5 DRG was removed, embedded in paraffin, and sectioned. Sections were then immunostained with antibodies to tyrosine hydroxylase (TH). To quantify the extent of the presence of sympathetic nerve fibers, we counted TH-immunoreactive fibers in the DRG using a light microscope equipped with a micrometer graticule. We counted the squares of the graticule, which contained TH-immunoreactive fibers for each of five randomly selected sections of the DRG. RESULTS: In the naïve group, TH-immunoreactive fibers were scarce in the DRG. α-antagonist injections from postoperative day 0 and 4 suppressed sympathetic nerve sprouting compared with the control group. α-antagonist injections from postoperative day 11 had no suppressant effect compared with the control group. CONCLUSION: The α-antagonist administered around the DRG could suppress neural plastic changes in the early phase after nerve injury. LEVEL OF EVIDENCE: N/A.

Sympathectomy and Sympathetic Blockade Reduce Pain Behavior Via Alpha-2 Adrenoceptor of the Dorsal Root Ganglion Neurons in a Lumbar Radiculopathy Model.

STUDY DESIGN: Animal experimental study with intervention. OBJECTIVE: We investigated whether sympathectomy and pharmacological sympathetic blockade reduced pain behavior and reversed adrenoceptor mRNA expression of the dorsal root ganglion (DRG) in a lumbar radiculopathy model. SUMMARY OF BACKGROUND DATA: The abnormal sympathetic-somatosensory interaction may underlie some forms of neuropathic pain. There are several reports that sympathectomy and pharmacological sympathetic blockades are often effective to treat neuropathic pain. However, its pathophysiological mechanisms remain obscure. METHODS: We used 91 male Sprague-Dawley rats. Just after root constriction (RC), the rats underwent sympathectomy or received 3 local injections of subtype-specific α-adrenergic receptor antagonists around the DRG. We evaluated the analgesic effects of sympathectomy and sympathetic blockade using behaviors indicative mechanical allodynia and thermal hyperalgesia. We estimated the mRNA expression levels of the DRG adrenoceptor subtypes using real time reverse transcription polymerase chain reaction. RESULTS: Sympathectomy and α2-antagonist significantly reduced the mechanical allodynia and thermal hyperalgesia after RC. Real time reverse transcription polymerase chain reaction analysis indicated that sympathectomy possibly reversed α2A- and α2B-adrenoceptors mRNA overexpression in the DRG after RC. CONCLUSION: We considered that pain behaviors of neuropathic pain are due, at least in part, to enhanced sympathetic noradrenergic transmission within the DRG. Suppression of sympathetic activity by reducing adrenergic release, α2-adrenoceptor stimulation, and/or α2-adrenoceptor upregulation in the DRG may relieve neuropathic pain. LEVEL OF EVIDENCE: 3.

The beginning of the calcium transient in rat embryonic heart.

Although many researchers have tried to observe the beginning of the heartbeat, no study has shown the beginning of the calcium transient. Here, we evaluate the beginning of the calcium transient in the Wistar rat heart. We first tried to reveal when the heart of the Wistar rat begins to contract because no previous study has evaluated the beginning of the heartbeat in Wistar rats. Observation of embryos transferred to a small incubator mounted on a microscope revealed that the heart primordium, the so-called cardiac crescent, began to contract at embryonic day 9.99-10.13. Observation of embryos loaded with fluo-3 AM revealed that the beginning of the calcium transient precedes the initiation of contraction which precedes the appearance of the linear heart tube. Nifedipine (1 µM), but not ryanodine (1 µM), abolished the calcium transients. These results indicate that calcium transients in the early embryonic period involve exclusively calcium entry through L-type calcium channels in contrast to the situation in mature hearts. This study provides the first demonstration of the relationship between morphological changes in the heart primordium and the beginning of the calcium transient and contraction.