Cardiological paradoxes, such as the obesity, smoker's, and French paradoxes, demonstrate complex physiological and epidemiological phenomena that often contradict expected clinical outcomes.
A paradox refers to 'a logically self-contradictory statement or a statement that runs contrary to one's expectation.'In cardiology, the word 'paradox' is common despite revolutionary and newer inventions/interventions.In the early medicine era, paradox in the pulse was described by Lomer in 1669 in a patient with pericardial constriction. 1As cardiology evolved as a science, various paradoxes were described, some of which are discussed. PULSUS PARADOXUSIn 1669, Lomer described the phenomenon of a decrease in pulse volume on inspiration in a patient with pericardial constriction. 1Later in 1850, Floyer and William described the same finding in patients with bronchial asthma. 1,2In 1873, Adolf Kussmaul, in the issue of 'Berliner Klinische Wochenschrift', coined the term 'pulsus paradoxus' for the peculiar phenomenon observed in 3 patients with constrictive pericarditis (CP).Pulsus paradoxus is defined as a decrease in systolic blood pressure of >10 mmHg during inspiration.The 'paradox' in the term 'pulsus paradoxus' is the fact that heart sounds are audible over the precordium, but the pulse disappears and is not felt on inspiration.Pulsus paradoxus is an important physical sign in various cardiac and non-cardiac conditions. 2 In patients with bronchial asthma, it is considered an ominous sign.In some patients with inapparent hypovolaemia, it can be one of the earliest signs of impending shock. 2,3Though the cuff sphygmomanometer remains the standard method for clinical demonstration of pulsus paradox, other methods like palpation of central pulses and arterial and pulse oximetry waveform analysis can also be used to demonstrate the paradox. MechanismUnder normal physiological conditions, arterial blood pressure falls during inspiration and increases during expiration due to intrathoracic pressure changes during the respiratory cycle, which are transmitted to cardiac chambers.Both these mechanisms lead to a decrease in stroke volume during inspiration.These respiratory changes are altered in patients Speaking for Ourselves with CP, acute exacerbation of asthma, and acute pulmonary thromboembolism due to various mechanisms that lead to pulsus paradoxus (Fig. 1).The mechanisms include
RAO et al. (Fri,) conducted a review in Cardiovascular diseases. Cardiological paradoxes, such as the obesity, smoker's, and French paradoxes, demonstrate complex physiological and epidemiological phenomena that often contradict expected clinical outcomes.
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