Cardiovascular adaptation to mudpack therapy in hypertensive subjects treated with different antihypertensive drugs

OBJECTIVE: In selected hypertensive subjects, cardiovascular adaptation to warm environments may be inadequate or even harmful: heating associated to mudpack therapy may cause unexpected hypotension. How different antihypertensive drugs may affect the cardiovascular response to mudpack therapy is poorly studied.
AIMS: To evaluate the effects of β-blockers and angiotensin II receptor antagonists/ACE inhibitors on the acute cardiovascular adaptation to mudpack treatment in SPA in elderly hypertensive patients.
PATIENTS AND METHODS: Thirty-one elderly subjects were divided in normotensive subjects (N; n=10) and hypertensive patients treated with ACE-inhibitors/Angiotensin II receptor antagonists (HTA; n=12) or with selective β1-blockers (HTB; n=9). Systolic (SBP) and diastolic (DBP) blood pressure were continuously recorded (10 min) in supine position, immediately before and during mudpack treatment (40°C). Heart rate (HR), stroke volume (SV), cardiac output (CO) and total peripheral resistance (TPR) were assessed.
RESULTS:
During mudpack treatment SBP did not significantly change in both HTA and N groups (132±11 and 112±13 mmHg, respectively), but significantly decreased in HTB (111±18 mmHg, p < 0.01 vs baseline) patients. HR increased in all groups (HTA: 72±10 bpm; HTB: 65±6 bpm; N: 70±10 bpm; p < 0.01 vs baseline). A significant reduction (p < 0.01 vs baseline) in SV and CO occurred in HTB, but not in HTA and N groups. TPR significantly increased in HTB (1335±464 dyn.s.cm-5, p < 0.01 vs baseline) but not in HTA and N subjects (1389±385 dyn.s.cm-5 and 1245±323 dyn.s.cm-5, respectively).
CONCLUSIONS: Mud treatment did not cause relevant haemodynamic changes in normotensive and HTA-treated hypertensive subjects. Conversely, β-blocking treatment apparently limited the cardiovascular adaptation to thermic stress, through a possible reduction in myocardial contractility, thereby, causing a significant decrease, although not dangerous, in systolic blood pressure.