14 Although it is standard practice to measure the QT interval from the beginning of the QRS complex to the end of the T wave, the actual methods of measurement have not been standardized. Because the QT interval is prolonged at slower heart rates and shortened at faster heart rates, many ...
如图中的a和b分别表示在理想状态下和自然环境中某生物种群的数量变化曲线。下列对阴影部分的解释正确的是( ) ①表示环境中影响种群增长的阻力 ②表示环境中允许种群增长的最大值 ③表示种群内迁出的个体数 ④表示通过生存斗争被淘汰的个体数
During sinus rhythm, the 12-lead electrocardiogram showed a complete left bundle branch block with a prolonged PR interval. During tachycardia, the QRS morphology was identical; however, no P waves were visible (Figure 1). The cycle length during tachycardia varied between 440 and 490 ms.Teis...
有心绞痛者心肌侧支循环比较丰富，这显示心绞痛或心肌缺血可以促进侧支循环的形成，从而对冠心病人具有保护作用。运动可以诱发心肌缺血，因而许多冠心病患者不敢运动或许多医生也警告患者避免运动。但运动有可能通过诱发可逆性心肌缺血，促进侧支循环的形成，增加心肌自我保护...
Torsade de pointes is widely thought to be triggered by reactivation of calcium channels, reactivation of a delayed sodium current, or a decreased outward potassium current that results in early afterdepolarization (EAD), in a condition with enhanced TDR usually associated with a prolonged QT interva...
In our case too, with VVI pacing, the pacing spikes were clearly related to P waves, while during AAI pacing, the spikes were related to the QRS, as described above. However, it is worthwhile to mention here that it would indeed be risky to test in a single chamber mode in a patient...
Aortic stenosis is a common valvular pathology and may also have atypical presentations outside the classic triad of chest pain, syncope, and shortness of breath. Some patients may not present with the symptoms of the triad. This patient instead presente
Medical grade wearable ECG based sensors usually record more than one channel and allow for a more detailed analysis, such as QRS morphology and repolarization abnormalities to assess conduction problems, site of premature beats and ischemia. For heart rate monitoring, a single channel tracing is ade...
Furthermore, a subset of cases that falls into the definition includes patients suffering prolonged sequelae due to the severity of SARS-CoV-2 infection itself, relating to underlying organ injury during the course of the infection or to hospitalization in an intensive care unit (ICU) setting and...
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