A routine technique revealed a heart keeping secrets
Una mujer de 50 años acudió a una cirugía de codo de rutina y salió con un marcapasos permanente: entre ambos momentos, una técnica anestésica habitual desveló un defecto eléctrico cardíaco que había permanecido silencioso durante décadas. Solo existe un caso previo documentado en la literatura médica mundial. El suceso, atendido por especialistas del Centro Médico Teknon de Barcelona, nos recuerda que el cuerpo humano guarda secretos que a veces solo emergen cuando algo aparentemente inocuo los roza.
- A los 25 minutos de una operación de codo sin complicaciones previstas, el monitor de anestesia detectó un bloqueo cardíaco completo: el corazón había perdido la coordinación eléctrica entre sus cámaras.
- El equipo quirúrgico detuvo la intervención de inmediato y activó los protocolos de emergencia, sin encontrar al principio ninguna causa evidente que explicara lo ocurrido.
- Un estudio electrofisiológico reveló la verdad oculta: la paciente tenía un trastorno de conducción cardíaca profundo y silencioso que el bloqueo simpático provocado por la anestesia había sacado a la luz.
- La solución fue definitiva pero eficaz: la implantación de un marcapasos permanente, tras el cual la paciente evolucionó favorablemente y permanece asintomática un año después.
- Los médicos responsables advierten que cualquier bloqueo cardíaco completo inesperado —incluso provocado por una causa transitoria— exige una evaluación cardiológica exhaustiva para descartar patología subyacente.
Una mujer de 50 años llegó al quirófano para una artrolisis de codo, una intervención de rutina con todos los controles preoperatorios en regla y un electrocardiograma sin alteraciones. El anestesiólogo realizó un bloqueo del plexo braquial supraclavicular, técnica estándar y ampliamente utilizada en cirugía de miembro superior. La operación comenzó sin incidencias, con el único efecto secundario esperado: un síndrome de Horner leve.
Veinticinco minutos después, el monitor registró un bloqueo cardíaco completo. Los impulsos eléctricos que coordinan las cámaras del corazón habían dejado de comunicarse, y un ritmo de escape lento —el sistema de reserva del corazón— tomó el control. Sin signos de toxicidad anestésica ni explicación inmediata, el equipo detuvo la cirugía y activó los protocolos de emergencia.
Lo que siguió fue una investigación clínica minuciosa. El Dr. Carlos Ramírez-Paesano y el Dr. Antonio Berruezo, director de la unidad de arritmias del Centro Médico Teknon de Barcelona, determinaron que el bloqueo simpático transitorio inducido por la anestesia había desvelado un trastorno de conducción profundo y silencioso que la paciente desconocía. Un estudio electrofisiológico lo confirmó.
La paciente recibió un marcapasos permanente y, un año más tarde, se encuentra asintomática. El caso —solo el segundo de este tipo en la literatura médica mundial, publicado en HeartRhythm Case Reports— trasciende su rareza estadística: cuando un procedimiento seguro desencadena un evento cardíaco inesperado, aunque la causa sea temporal, el cuerpo está enviando una señal que no puede ignorarse.
A 50-year-old woman went in for routine elbow surgery—an arthrolysis to free up a stiff joint—with all the standard preoperative clearances in place. Her heart looked fine on the electrocardiogram. The anesthesiologist administered a supraclavicular brachial plexus block, a technique so common and so safe that it's considered the standard approach for upper limb procedures. The block worked. She developed the expected minor side effect, Horner's syndrome—a drooping eyelid, a constricted pupil—and the surgery began.
Twenty-five minutes into the procedure, the anesthesia monitor registered something alarming: a complete heart block. The electrical impulses that normally coordinate the heart's chambers had stopped communicating entirely. A slow escape rhythm took over—the heart's backup system, but a fragile one. There were no signs of local anesthetic toxicity, no obvious explanation for what was happening. The surgical team halted the operation immediately and activated emergency protocols.
What unfolded over the following hours and days was a medical detective story. The anesthesiologists and cardiologists who treated her—including Dr. Carlos Ramírez-Paesano from Centro Médico Teknon in Barcelona and Dr. Antonio Berruezo, director of arrhythmia services at the same institution—realized they were looking at something extraordinary. The temporary blockade of the sympathetic nervous system caused by the anesthesia technique had exposed a hidden electrical defect in her heart. An electrophysiological study confirmed it: she had a conduction delay deep within the heart's electrical system, a problem that had been silent, undetected, until this moment.
The diagnosis demanded action. She received a permanent pacemaker to protect her from future episodes of complete heart block. A year later, she remained symptom-free, her heart steady and regulated by the device.
The case is only the second of its kind ever documented in the medical literature—a complication so rare that most cardiologists and anesthesiologists will never encounter it. Yet it carries a lesson that extends far beyond its statistical rarity. Dr. Ramírez-Paesano emphasized that a technique considered safe and widely used can, in specific circumstances, unmask underlying cardiac pathology that would otherwise remain hidden. The article, published in HeartRhythm Case Reports, details the clinical management and proposes a neurochemical explanation involving the sympathetic nervous system and the nucleus of the solitary tract—the brain's control center for autonomic functions.
Dr. Berruezo underscored the broader implication: when a complete heart block appears in a patient with no known heart disease, clinicians must suspect an underlying conduction disorder that has been silent until triggered. Even if the trigger is temporary—even if it's something as routine as an anesthesia block—the event demands thorough cardiac evaluation. The woman's case, in other words, is not just a curiosity. It is a reminder that the body sometimes keeps secrets, and that the safest procedures can occasionally reveal them.
Citas Notables
A technique widely used and considered safe can, in specific situations, reveal underlying cardiac pathologies that had not been diagnosed— Dr. Carlos Ramírez-Paesano, anesthesiologist, Centro Médico Teknon
The appearance of complete heart block in a patient without known heart disease should raise suspicion of a previously silent conduction disorder, underscoring the importance of thorough cardiac evaluation when such events occur— Dr. Antonio Berruezo, cardiologist and director of arrhythmia services, Instituto del Corazón Quirónsalud Teknon
La Conversación del Hearth Otra perspectiva de la historia
Why would a temporary nerve block unmask a heart problem that was completely hidden before?
The sympathetic nervous system normally keeps the heart's electrical system in balance. When you block that system with the anesthesia technique, you remove that support. If there's already a weak spot in the conduction pathway—something that was never diagnosed—suddenly that weakness becomes critical.
So the anesthesia didn't cause the heart block. It revealed it.
Exactly. The woman's heart had a conduction defect all along. She could have lived her whole life without knowing, or it might have surfaced during stress or exertion. The anesthesia just happened to be the trigger that exposed it.
How many people might have this same hidden defect without knowing?
That's the unsettling question. This is only the second documented case in the entire medical literature, but that doesn't mean it's rare—it might just mean it's rarely triggered. Most people with this kind of conduction delay never have an event that unmasks it.
What changes for patients now?
The case makes doctors more cautious about interpreting unexpected cardiac events during anesthesia. Even if the trigger seems temporary, they know to investigate whether something deeper is wrong. For this patient, it meant getting a pacemaker and living safely. For others, it might mean earlier diagnosis of a problem that would have caused trouble later.